# Calendar

Calendar
You are encouraged to solve this task according to the task description, using any language you may know.

Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices:

• A line printer with a width of 132 characters.
• An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43.

(Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.)

Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar.

This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983.

THE REAL PROGRAMMER'S NATURAL HABITAT
"Taped to the wall is a line-printer Snoopy calender for the year 1969."


For further Kudos see task CALENDAR, where all code is to be in UPPERCASE.

For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder.

For other calendar-related tasks, see Five weekends.

## 360 Assembly

Translation of: Free Basic

This program uses no external functions but two ASSIST macros (XDECO, XPRNT) to keep the code as short as possible.

*        calendar                  08/06/2016CALENDAR CSECT         USING  CALENDAR,R13       base register         B      72(R15)            skip savearea         DC     17F'0'             savearea         STM    R14,R12,12(R13)    prolog         ST     R13,4(R15)         "         ST     R15,8(R13)         "          LR     R13,R15            "         L      R4,YEAR            year         SRDA   R4,32              .         D      R4,=F'4'           year//4         LTR    R4,R4              if year//4=0         BNZ    LYNOT         L      R4,YEAR            year         SRDA   R4,32              .         D      R4,=F'100'         year//100         LTR    R4,R4              if year//100=0         BNZ    LY          L      R4,YEAR            year         SRDA   R4,32              .         D      R4,=F'400'         if year//400         LTR    R4,R4              if year//400=0         BNZ    LYNOTLY       MVC    ML+2,=H'29'        ml(2)=29  leapyearLYNOT    SR     R10,R10            ltd1=0         LA     R6,1               i=1LOOPI1   C      R6,=F'31'          do i=1 to 31         BH     ELOOPI1         XDECO  R6,XDEC            edit i         LA     R14,TD1            td1         AR     R14,R10            td1+ltd1         MVC    0(3,R14),XDEC+9    sub(td1,ltd1+1,3)=pic(i,3)         LA     R10,3(R10)         ltd1+3         LA     R6,1(R6)           i=i+1         B      LOOPI1ELOOPI1  LA     R6,1               i=1LOOPI2   C      R6,=F'12'          do i=1 to 12         BH     ELOOPI2         ST     R6,M               m=i         MVC    D,=F'1'            d=1         MVC    YY,YEAR            yy=year         L      R4,M               m         C      R4,=F'3'           if m<3         BNL    GE3         L      R2,M               m         LA     R2,12(R2)          m+12         ST     R2,M               m=m+12         L      R2,YY              yy         BCTR   R2,0               yy-1         ST     R2,YY              yy=yy-1GE3      L      R2,YY              yy         LR     R1,R2              yy         SRA    R1,2               yy/4         AR     R2,R1              yy+(yy/4)                  L      R4,YY              yy         SRDA   R4,32              .         D      R4,=F'100'         yy/100               SR     R2,R5              yy+(yy/4)-(yy/100)         L      R4,YY              yy         SRDA   R4,32              .         D      R4,=F'400'         yy/400                                   AR     R2,R5              yy+(yy/4)-(yy/100)+(yy/400)           A      R2,D               r2=yy+(yy/4)-(yy/100)+(yy/400)+d         LA     R5,153             153          M      R4,M               153*m                     LA     R5,8(R5)           153*m+8                                              D      R4,=F'5'           (153*m+8)/5                        AR     R5,R2              ((153*m+8)/5+r2           LA     R4,0               .         D      R4,=F'7'           r4=mod(r5,7)  0=sun 1=mon ... 6=sat                           LTR    R4,R4              if j=0         BNZ    JNE0         LA     R4,7               j=7JNE0     BCTR   R4,0               j-1         MH     R4,=H'3'           j*3         LR     R10,R4             j1=j*3         LR     R1,R6              i         SLA    R1,1               *2         LH     R11,ML-2(R1)       ml(i)         MH     R11,=H'3'          j2=ml(i)*3         MVC    TD2,BLANK          td2=' '         LA     R4,TD1             @td1         LR     R5,R11             j2         LA     R2,TD2             @td2         AR     R2,R10             @td2+j1         LR     R3,R5              j2         MVCL   R2,R4              sub(td2,j1+1,j2)=sub(td1,1,j2)         LR     R1,R6              i         MH     R1,=H'144'         *144         LA     R14,DA-144(R1)     @da(i)         MVC    0(144,R14),TD2     da(i)=td2         LA     R6,1(R6)           i=i+1         B      LOOPI2ELOOPI2  L      R1,YEAR            year         XDECO  R1,PG+23           edit year         XPRNT  PG,35              print year         MVC    WDLINE,BLANK       wdline=' '         LA     R10,1              lwdline=1         LA     R8,1               k=1 LOOPK3   C      R8,=F'3'           do k=1 to 3         BH     ELOOPK3         LA     R4,WDLINE          @wdline         AR     R4,R10             +lwdline         MVC    0(20,R4),WDNA      sub(wdline,lwdline+1,20)=wdna         LA     R10,20(R10)        lwdline=lwdline+20         C      R8,=F'3'           if k<3         BNL    ITERK3         LA     R10,2(R10)         lwdline=lwdline+2ITERK3   LA     R8,1(R8)           k=k+1         B      LOOPK3ELOOPK3  LA     R6,1               i=1LOOPI4   C      R6,=F'12'          do i=1 to 12 by 3         BH     ELOOPI4         MVC    MOLINE,BLANK       moline=' '         LA     R10,6              lmoline=6         LR     R8,R6              k=iLOOPK4   LA     R2,2(R6)           i+2         CR     R8,R2              do k=i to i+2         BH     ELOOPK4         LR     R1,R8              k         MH     R1,=H'10'          *10         LA     R3,MO-10(R1)       mo(k)         LA     R4,MOLINE          @moline         AR     R4,R10             +lmoline         MVC    0(10,R4),0(R3)     sub(moline,lmoline+1,10)=mo(k)         LA     R10,22(R10)        lmoline=lmoline+22         LA     R8,1(R8)           k=k+1         B      LOOPK4ELOOPK4  XPRNT  MOLINE,L'MOLINE    print months         XPRNT  WDLINE,L'WDLINE    print days of week         LA     R7,1               j=1LOOPJ4   C      R7,=F'106'         do j=1 to 106 by 21         BH     ELOOPJ4         MVC    PG,BLANK           clear buffer         LA     R9,PG              pgi=0         LR     R8,R6              k=iLOOPK5   LA     R2,2(R6)           i+2         CR     R8,R2              do k=i to i+2         BH     ELOOPK5         LR     R1,R8              k         MH     R1,=H'144'         *144         LA     R4,DA-144(R1)      da(k)         BCTR   R4,0               -1         AR     R4,R7              +j         MVC    0(21,R9),0(R4)     substr(da(k),j,21)         LA     R9,22(R9)          pgi=pgi+22         LA     R8,1(R8)           k=k+1         B      LOOPK5ELOOPK5  XPRNT  PG,L'PG            print buffer         LA     R7,21(R7)          j=j+21         B      LOOPJ4ELOOPJ4  LA     R6,3(R6)           i=i+3         B      LOOPI4ELOOPI4  L      R13,4(0,R13)       epilog          LM     R14,R12,12(R13)    "         XR     R15,R15            "         BR     R14                exit         LTORGYEAR     DC     F'1969'            <==MO       DC     CL10' January  ',CL10' February ',CL10'  March   '         DC     CL10'  April   ',CL10'   May    ',CL10'   June   '         DC     CL10'   July   ',CL10'  August  ',CL10'September '         DC     CL10' October  ',CL10' November ',CL10' December 'ML       DC     H'31',H'28',H'31',H'30',H'31',H'30'         DC     H'31',H'31',H'30',H'31',H'30',H'31'WDNA     DC     CL20'Mo Tu We Th Fr Sa Su'M        DS     FD        DS     FYY       DS     FTD1      DS     CL93TD2      DS     CL144MOLINE   DS     CL66WDLINE   DS     CL66PG       DC     CL66' 'XDEC     DS     CL12BLANK    DC     CL144' 'DA       DS     12CL144         YREG         END    CALENDAR
Output:
                               2016
January               February               March
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3   1  2  3  4  5  6  7      1  2  3  4  5  6
4  5  6  7  8  9 10   8  9 10 11 12 13 14   7  8  9 10 11 12 13
11 12 13 14 15 16 17  15 16 17 18 19 20 21  14 15 16 17 18 19 20
18 19 20 21 22 23 24  22 23 24 25 26 27 28  21 22 23 24 25 26 27
25 26 27 28 29 30 31  29                    28 29 30 31

April                  May                   June
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3                     1         1  2  3  4  5
4  5  6  7  8  9 10   2  3  4  5  6  7  8   6  7  8  9 10 11 12
11 12 13 14 15 16 17   9 10 11 12 13 14 15  13 14 15 16 17 18 19
18 19 20 21 22 23 24  16 17 18 19 20 21 22  20 21 22 23 24 25 26
25 26 27 28 29 30     23 24 25 26 27 28 29  27 28 29 30
30 31
July                 August              September
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3   1  2  3  4  5  6  7            1  2  3  4
4  5  6  7  8  9 10   8  9 10 11 12 13 14   5  6  7  8  9 10 11
11 12 13 14 15 16 17  15 16 17 18 19 20 21  12 13 14 15 16 17 18
18 19 20 21 22 23 24  22 23 24 25 26 27 28  19 20 21 22 23 24 25
25 26 27 28 29 30 31  29 30 31              26 27 28 29 30

October               November              December
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2      1  2  3  4  5  6            1  2  3  4
3  4  5  6  7  8  9   7  8  9 10 11 12 13   5  6  7  8  9 10 11
10 11 12 13 14 15 16  14 15 16 17 18 19 20  12 13 14 15 16 17 18
17 18 19 20 21 22 23  21 22 23 24 25 26 27  19 20 21 22 23 24 25
24 25 26 27 28 29 30  28 29 30              26 27 28 29 30 31
31


We first specify a "Printable_Calendar" package (printable_calendar.ads). One can easily override the default names for weekdays and months, see the Calendar_-_for_"real"_programmers#Ada task.

with Ada.Calendar.Formatting; package Printable_Calendar is    subtype String20 is String(1 .. 20);   type Month_Rep_Type is array (Ada.Calendar.Month_Number) of String20;    type Description is record      Weekday_Rep: String20;      Month_Rep: Month_Rep_Type;   end record;   -- for internationalization, you only need to define a new description    Default_Description: constant Description :=     (Weekday_Rep =>       "Mo Tu We Th Fr Sa So",      Month_Rep   =>      ("      January       ", "      February      ", "       March        ",       "       April        ", "        May         ", "        June        ",       "        July        ", "       August       ", "      September     ",       "       October      ", "      November      ", "      December      "));    type Calendar (<>) is tagged private;    -- Initialize a calendar for devices with 80- or 132-characters per row   function Init_80(Des: Description := Default_Description) return Calendar;   function Init_132(Des: Description := Default_Description) return Calendar;    -- the following procedures output to standard IO; override if neccessary   procedure New_Line(Cal: Calendar);   procedure Put_String(Cal: Calendar; S: String);    -- the following procedures do the real stuff   procedure Print_Line_Centered(Cal: Calendar'Class; Line: String);   procedure Print(Cal: Calendar'Class;                   Year:  Ada.Calendar.Year_Number;                   Year_String: String); -- this is the main Thing private      type Calendar is tagged record      Columns, Rows, Space_Between_Columns: Positive;      Left_Space: Natural;       Weekday_Rep: String20;      Month_Rep: Month_Rep_Type;   end record; end Printable_Calendar;

We continue with the implementation (printable_calendar.ads):

with Ada.Text_IO; package body Printable_Calendar is    use Ada.Calendar;   package F renames Ada.Calendar.Formatting;    function Days_Per_Month(Year: Year_Number; Month: Month_Number)                          return Day_Number is   begin      case Month is         when 1 | 3 | 5 | 7 | 8 | 10 | 12 => return 31;         when 4 | 6 | 9 | 11              => return 30;         when 2 =>            if Year mod 4 /= 0 then               return 28;            elsif Year mod 100 /= 0 then               return 29;            elsif Year mod 400 /= 0 then               return 28;            else               return 29;            end if;      end case;   end Days_Per_Month;    type Full_Month_Rep is array (1 .. 6) of String20;   function Generate_Printable_Month (Y: Ada.Calendar.Year_Number;                                      M: Ada.Calendar.Month_Number)                                     return Full_Month_Rep is       X: Full_Month_Rep := (others => "                    ");      -- If X=Generate_Printable_Month(2011, 01), the result could be      --  "       January      ", -- Month_Rep(01)      --  "Mo Tu We Th Fr Sa Su"  -- Weekday_Rep      --  "                1  2"  -- X(1)      --  " 3  4  5  6  7  8  9"  -- X(2)      --  "10 11 12 13 14 15 16"  -- X(3)      --  "17 18 19 20 21 22 23"  -- X(4)      --  "24 25 26 27 28 29 30"  -- X(5)      --  "31                  "  -- X(6)       Row:       Integer range 1 .. 6  := 1;      Day_Index: constant array(F.Day_Name) of Positive        := (1, 4, 7, 10, 13, 16, 19);   begin      for I in 1 .. Days_Per_Month(Y, M) loop         declare           Weekday: constant F.Day_Name    := F.Day_Of_Week(F.Time_Of(Y, M, I));           Pos: constant Positive          := Day_Index(Weekday);           Cleartext_Name: constant String := Day_Number'Image(I);           L: constant Positive            := Cleartext_Name'Last;         begin            X(Row)(Pos .. Pos+1) := Cleartext_Name(L-1 .. L);            if F."="(Weekday, F.Sunday) then               Row := Row + 1;            end if;         end;      end loop;      return X;   end Generate_Printable_Month;     procedure Print(Cal: Calendar'class;                   Year:  Ada.Calendar.Year_Number;                   Year_String: String) is       The_Month: Month_Number := Month_Number'First;       procedure Write_Space(Length: Natural) is      begin         for I in 1 .. Length loop            Cal.Put_String(" ");         end loop;      end Write_Space;       Year_Rep: array(Month_Number) of Full_Month_Rep;    begin      -- print the year      Cal.Print_Line_Centered(Year_String);       -- generate a printable form for all the months      for Month in Month_Number loop         Year_Rep(Month) := Generate_Printable_Month(Year, Month);      end loop;       begin         while True loop             -- new line            Cal.New_Line;             -- write month names            Write_Space(Cal.Left_Space);            for Month in The_Month .. The_Month+Cal.Columns-2 loop               Cal.Put_String(Cal.Month_Rep(Month));               Write_Space(Cal.Space_Between_Columns);            end loop;            Cal.Put_String(Cal.Month_Rep(The_Month+Cal.Columns-1));            Cal.New_Line;             -- write "Mo Tu .. So" - or whatever is defined by Weekday_Rep            Write_Space(Cal.Left_Space);            for Month in The_Month .. The_Month+Cal.Columns-2 loop               Cal.Put_String(Cal.Weekday_Rep);               Write_Space(Cal.Space_Between_Columns);            end loop;            Cal.Put_String(Cal.Weekday_Rep);            Cal.New_Line;             -- write the dates            for I in 1 .. 6 loop               Write_Space(Cal.Left_Space);               for Month in The_Month .. The_Month+Cal.Columns-2 loop                  Cal.Put_String(Year_Rep(Month)(I));                  Write_Space(Cal.Space_Between_Columns);               end loop;            Cal.Put_String(Year_Rep(The_Month+Cal.Columns-1)(I));            Cal.New_Line;            end loop;             The_Month := The_Month + Cal.Columns;            -- this will eventually raise Constraint_Error to terminate the loop         end loop;      exception         when Constraint_Error => null;      end;   end Print;    procedure New_Line(Cal: Calendar) is   begin      Ada.Text_IO.New_Line;   end New_Line;    procedure Put_String(Cal: Calendar; S: String) is   begin      Ada.Text_IO.Put(S);   end Put_String;    procedure Print_Line_Centered(Cal: Calendar'Class; Line: String) is      Width : constant Positive := Cal.Columns*20        + (Cal.Columns-1)*Cal.Space_Between_Columns        + Cal.Left_Space;   begin      if Line'Length    >= Width-1 then         Cal.Put_String(Line);         Cal.New_Line;      else         Print_Line_Centered(Cal, " " & Line & " ");      end if;   end Print_Line_Centered;    function Init_80(Des: Description := Default_Description) return Calendar is      X: Calendar:=        (Columns => 3, Rows => 4, Space_Between_Columns => 4,         Left_Space => 1,         Weekday_Rep =>  Des.Weekday_Rep,         Month_Rep   =>  Des.Month_Rep        );   begin      return X;   end Init_80;    function Init_132(Des: Description := Default_Description) return Calendar is      X: Calendar:=        (Columns => 6, Rows => 2, Space_Between_Columns => 2,         Left_Space => 1,         Weekday_Rep =>  Des.Weekday_Rep,         Month_Rep   =>  Des.Month_Rep        );   begin      return X;   end Init_132; end Printable_Calendar;

Now, the main program is really simple:

with Printable_Calendar; procedure Cal is    C: Printable_Calendar.Calendar := Printable_Calendar.Init_80; begin   C.Print_Line_Centered("[reserved for Snoopy]");   C.New_Line;   C.Print(1969, "Nineteen-Sixty-Nine");end Cal;

Here is the output:

                        [reserved for Snoopy]

Nineteen-Sixty-Nine

January                 February                 March
Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So
1  2  3  4  5                    1  2                    1  2
6  7  8  9 10 11 12     3  4  5  6  7  8  9     3  4  5  6  7  8  9
13 14 15 16 17 18 19    10 11 12 13 14 15 16    10 11 12 13 14 15 16
20 21 22 23 24 25 26    17 18 19 20 21 22 23    17 18 19 20 21 22 23
27 28 29 30 31          24 25 26 27 28          24 25 26 27 28 29 30
31

April                    May                     June
Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So
1  2  3  4  5  6              1  2  3  4                       1
7  8  9 10 11 12 13     5  6  7  8  9 10 11     2  3  4  5  6  7  8
14 15 16 17 18 19 20    12 13 14 15 16 17 18     9 10 11 12 13 14 15
21 22 23 24 25 26 27    19 20 21 22 23 24 25    16 17 18 19 20 21 22
28 29 30                26 27 28 29 30 31       23 24 25 26 27 28 29
30

July                   August                 September
Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So
1  2  3  4  5  6                 1  2  3     1  2  3  4  5  6  7
7  8  9 10 11 12 13     4  5  6  7  8  9 10     8  9 10 11 12 13 14
14 15 16 17 18 19 20    11 12 13 14 15 16 17    15 16 17 18 19 20 21
21 22 23 24 25 26 27    18 19 20 21 22 23 24    22 23 24 25 26 27 28
28 29 30 31             25 26 27 28 29 30 31    29 30

October                November                December
Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So    Mo Tu We Th Fr Sa So
1  2  3  4  5                    1  2     1  2  3  4  5  6  7
6  7  8  9 10 11 12     3  4  5  6  7  8  9     8  9 10 11 12 13 14
13 14 15 16 17 18 19    10 11 12 13 14 15 16    15 16 17 18 19 20 21
20 21 22 23 24 25 26    17 18 19 20 21 22 23    22 23 24 25 26 27 28
27 28 29 30 31          24 25 26 27 28 29 30    29 30 31  

To get a 132-character-wide output, you just have to replace "Init_80" by "Init_132" in the main program.

## ALGOL 68

Works with: ALGOL 68 version Revision 1 - no extensions to language used
Works with: ALGOL 68G version Any - tested with release 1.18.0-9h.tiny.
#!/usr/local/bin/a68g --script # PROC print calendar = (INT year, page width)VOID: (   []STRING month names = (      "January","February","March","April","May","June",      "July","August","September","October","November","December"),    weekday names = ("Su","Mo","Tu","We","Th","Fr","Sa");  FORMAT weekday fmt = $g,n(UPB weekday names - LWB weekday names)(" "g)$;   # Juggle the calendar format to fit the printer/screen width #  INT day width = UPB weekday names[1], day gap=1;  INT month width = (day width+day gap) * UPB weekday names-1;  INT month heading lines = 2;  INT month lines = (31 OVER UPB weekday names+month heading lines+2); # +2 for head/tail weeks #  INT year cols = (page width+1) OVER (month width+1);  INT year rows = (UPB month names-1)OVER year cols + 1;  INT month gap = (page width - year cols*month width + 1)OVER year cols;  INT year width = year cols*(month width+month gap)-month gap;  INT year lines = year rows*month lines;   MODE MONTHBOX = [month lines, month width]CHAR;  MODE YEARBOX  = [year  lines, year  width]CHAR;   INT week start = 1; # Sunday #   PROC days in month = (INT year, month)INT:    CASE month IN 31,      IF year MOD 4 EQ 0 AND year MOD 100 NE 0 OR year MOD 400 EQ 0 THEN 29 ELSE 28 FI,      31, 30, 31, 30, 31, 31, 30, 31, 30, 31    ESAC;   PROC day of week = (INT year, month, day)INT: (    # Day of the week by Zeller’s Congruence algorithm from 1887 #    INT y := year, m := month, d := day, c;    IF m <= 2 THEN m +:= 12; y -:= 1 FI;    c := y OVER 100;    y %*:= 100;    (d - 1 + ((m + 1) * 26) OVER 10 + y + y OVER 4 + c OVER 4 - 2 * c) MOD 7  );   MODE SIMPLEOUT = UNION(STRING, []STRING, INT);   PROC cputf = (REF[]CHAR out, FORMAT fmt, SIMPLEOUT argv)VOID:(    FILE f; STRING s; associate(f,s);    putf(f, (fmt, argv));    out[:UPB s]:=s;    close(f)  );   PROC month repr = (INT year, month)MONTHBOX:(    MONTHBOX month box; FOR line TO UPB month box DO month box[line,]:=" "* 2 UPB month box OD;    STRING month name = month names[month];   # center the title #    cputf(month box[1,(month width - UPB month name ) OVER 2+1:], $g$, month name);    cputf(month box[2,], weekday fmt, weekday names);     INT first day := day of week(year, month, 1);    FOR day TO days in month(year, month) DO      INT line = (day+first day-week start) OVER UPB weekday names + month heading lines + 1;      INT char =((day+first day-week start) MOD UPB weekday names)*(day width+day gap) + 1;      cputf(month box[line,char:char+day width-1],$g(-day width)$, day)    OD;    month box  );   PROC year repr = (INT year)YEARBOX:(    YEARBOX year box;    FOR line TO UPB year box DO year box[line,]:=" "* 2 UPB year box OD;    FOR month row FROM 0 TO year rows-1 DO      FOR month col FROM 0 TO year cols-1 DO        INT month = month row * year cols + month col + 1;        IF month > UPB month names THEN          done        ELSE          INT month col width = month width+month gap;          year box[            month row*month lines+1 : (month row+1)*month lines,            month col*month col width+1 : (month col+1)*month col width-month gap          ] := month repr(year, month)        FI      OD    OD;    done: year box  );   INT center = (year cols*(month width+month gap) - month gap - 1) OVER 2;  INT indent = (page width - year width) OVER 2;   printf((    $n(indent + center - 9)k g l$, "[Insert Snoopy here]",    $n(indent + center - 1)k 4d l$, year, $l$,    $n(indent)k n(year width)(g) l$, year repr(year)  ))); main: (CO inspired by http://www.ee.ryerson.ca/~elf/hack/realmen.html           Real Programmers Don't Use PASCAL - Ed Post            Datamation, volume 29 number 7, July 1983              THE REAL PROGRAMMER'S NATURAL HABITAT"Taped to the wall is a line-printer Snoopy calender for the year 1969."CO  INT mankind stepped on the moon = 1969,      line printer width = 80; # as at 1969! #  print calendar(mankind stepped on the moon, line printer width))

Output:

                             [Insert Snoopy here]
1969

January                    February                    March
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4                          1                          1
5  6  7  8  9 10 11        2  3  4  5  6  7  8        2  3  4  5  6  7  8
12 13 14 15 16 17 18        9 10 11 12 13 14 15        9 10 11 12 13 14 15
19 20 21 22 23 24 25       16 17 18 19 20 21 22       16 17 18 19 20 21 22
26 27 28 29 30 31          23 24 25 26 27 28          23 24 25 26 27 28 29
30 31
April                       May                        June
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4  5                    1  2  3        1  2  3  4  5  6  7
6  7  8  9 10 11 12        4  5  6  7  8  9 10        8  9 10 11 12 13 14
13 14 15 16 17 18 19       11 12 13 14 15 16 17       15 16 17 18 19 20 21
20 21 22 23 24 25 26       18 19 20 21 22 23 24       22 23 24 25 26 27 28
27 28 29 30                25 26 27 28 29 30 31       29 30

July                      August                   September
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4  5                       1  2           1  2  3  4  5  6
6  7  8  9 10 11 12        3  4  5  6  7  8  9        7  8  9 10 11 12 13
13 14 15 16 17 18 19       10 11 12 13 14 15 16       14 15 16 17 18 19 20
20 21 22 23 24 25 26       17 18 19 20 21 22 23       21 22 23 24 25 26 27
27 28 29 30 31             24 25 26 27 28 29 30       28 29 30
31
October                    November                   December
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4                          1           1  2  3  4  5  6
5  6  7  8  9 10 11        2  3  4  5  6  7  8        7  8  9 10 11 12 13
12 13 14 15 16 17 18        9 10 11 12 13 14 15       14 15 16 17 18 19 20
19 20 21 22 23 24 25       16 17 18 19 20 21 22       21 22 23 24 25 26 27
26 27 28 29 30 31          23 24 25 26 27 28 29       28 29 30 31
30


## AutoHotkey

Calendar(Yr){	LastDay := [], Day := []	Titles =	(ltrim	______January_________________February_________________March_______	_______April____________________May____________________June________	________July___________________August_________________September_____	______October_________________November________________December______	)	StringSplit, title, titles, n	Res := "________________________________" Yr "rn" 	loop 4 {										; 4 Vertical Sections		Day[1]:=Yr SubStr("0" A_Index*3 -2, -1) 01		Day[2]:=Yr SubStr("0" A_Index*3 -1, -1) 01		Day[3]:=Yr SubStr("0" A_Index*3   , -1) 01		Res .= "rn" title%A_Index% "rnSu Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa"		loop , 6 {									; 6 Weeks max per month			Week := A_Index, Res .= "rn"			loop, 21 {								; 3 weeks times 7 days				Mon := Ceil(A_Index/7), ThisWD := Mod(A_Index-1,7)+1				FormatTime, WD, % Day[Mon], WDay				FormatTime, dd, % Day[Mon], dd				if (WD>ThisWD) {					Res .= "__ "					continue				}				dd := ((Week>3) && dd <10) ? "__" : dd, Res .= dd " ", LastDay[Mon] := Day[Mon], Day[Mon] +=1, Days				Res .= ((wd=7) && A_Index < 21) ? "___" : ""					FormatTime, dd, % Day[Mon], dd			}		}		Res .= "rn"	}	StringReplace, Res, Res,_,%A_Space%, all	Res:=RegExReplace(Res,"am)(^|\s)\K0", " ")	return res}
Examples:
Gui, font,s8, COURIERGui, add, edit, vYr w40 r1 Limit4 Number, 1969Gui, add, edit, vEdit2 w580 r38Gui, Add, Button, Default Hidden gSubmitGui, show Submit:Gui, Submit, NoHideGuiControl,, Edit2, % Calendar(Yr)return GuiEscape:GuiClose:ExitAppreturn
Outputs:
                                1969

January                February                  March
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1                       1
5  6  7  8  9 10 11     2  3  4  5  6  7  8     2  3  4  5  6  7  8
12 13 14 15 16 17 18     9 10 11 12 13 14 15     9 10 11 12 13 14 15
19 20 21 22 23 24 25    16 17 18 19 20 21 22    16 17 18 19 20 21 22
26 27 28 29 30 31       23 24 25 26 27 28       23 24 25 26 27 28 29
30 31

April                    May                    June
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                 1  2  3     1  2  3  4  5  6  7
6  7  8  9 10 11 12     4  5  6  7  8  9 10     8  9 10 11 12 13 14
13 14 15 16 17 18 19    11 12 13 14 15 16 17    15 16 17 18 19 20 21
20 21 22 23 24 25 26    18 19 20 21 22 23 24    22 23 24 25 26 27 28
27 28 29 30             25 26 27 28 29 30 31    29 30

July                   August                 September
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                    1  2        1  2  3  4  5  6
6  7  8  9 10 11 12     3  4  5  6  7  8  9     7  8  9 10 11 12 13
13 14 15 16 17 18 19    10 11 12 13 14 15 16    14 15 16 17 18 19 20
20 21 22 23 24 25 26    17 18 19 20 21 22 23    21 22 23 24 25 26 27
27 28 29 30 31          24 25 26 27 28 29 30    28 29 30
31

October                November                December
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1        1  2  3  4  5  6
5  6  7  8  9 10 11     2  3  4  5  6  7  8     7  8  9 10 11 12 13
12 13 14 15 16 17 18     9 10 11 12 13 14 15    14 15 16 17 18 19 20
19 20 21 22 23 24 25    16 17 18 19 20 21 22    21 22 23 24 25 26 27
26 27 28 29 30 31       23 24 25 26 27 28 29    28 29 30 31
30                                           

 #include <Date.au3> ; Set the count of characters in each line, minimum is 20 - one month.Global $iPrintSize = 132 ; Set the count of months, you want to print side by side. With "0" it calculates automatically.; The number will corrected, if it not allowed to print in an rectangle.; If your print size is to small for given count, it will set back to automatically calculation.Global$iSideBySide = 3 ; Set the count of spaces between months.Global $iSpace = 4 _CreateCalendar( 1969 ) Func _CreateCalendar($_iYear)	Local $aMon[12] = [' January ', ' February ', ' March ', _ ' April ', ' May ', ' June ', _ ' July ', ' August ', ' September ', _ ' October ', ' November ', ' December '] Local$sHead = 'Mo Tu We Th Fr Sa Su'	Local $aDaysInMonth[12] = [31,28,31,30,31,30,31,31,30,31,30,31] If _DateIsLeapYear($_iYear) Then $aDaysInMonth[1] = 29 ; == assign date in weekday table for the whole year Local$aAllDaysInMonth[6][7][12]   ; [ lines ][ weekdays ][ months ]	Local $iDay = 1,$iShift	For $i = 1 To 12$iShift = _DateToDayOfWeekISO($_iYear,$i, 1) -1		For $j = 0 To 5 For$k = $iShift To 6$aAllDaysInMonth[$j][$k][$i-1] =$iDay				$iDay += 1 If$iDay > $aDaysInMonth[$i-1] Then ExitLoop(2)			Next			$iShift = 0 Next$iDay = 1	Next 	; == check given side by side count, calculate if needed	If $iSideBySide > 0 Then If$iPrintSize < ($iSideBySide *(20 +$iSpace) -$iSpace) Then$iSideBySide = 0	EndIf	Switch $iSideBySide Case 0$iSideBySide = Int($iPrintSize /(20 +$iSpace))			If $iPrintSize < 20 Then Return _PrintLine('Escape: Size Error') If$iPrintSize < (20 +$iSpace) Then$iSideBySide = 1		Case 5			$iSideBySide = 4 Case 7 To 11$iSideBySide = 6	EndSwitch 	; == create space string	Local $sSpace = '' For$i = 1 To $iSpace$sSpace &= ' '	Next 	; == print header	_PrintLine(@LF)	_PrintLine('[ here is Snoopy ]', @LF)	_PrintLine(StringRegExpReplace($_iYear, '(\d)(\d)(\d)(\d)', '$1 $2$3 $4'), @LF) ; == create data for each line, in dependence to count of months in one line Local$sLine, $iRight,$sTmp1, $sTmp2 For$n = 0 To 12 /$iSideBySide -1$sTmp1 = ''		$sTmp2 = '' For$z = 0 To $iSideBySide -1$sTmp1 &= $aMon[$iSideBySide *$n+$z] & $sSpace$sTmp2 &= $sHead &$sSpace		Next		_PrintLine(StringTrimRight($sTmp1,$iSpace))		_PrintLine(StringTrimRight($sTmp2,$iSpace))		For $j = 0 To 5$sLine = ''			For $i = 1 To$iSideBySide				For $k = 0 To 6$iRight = 3					If $k = 0 Then$iRight = 2					$sLine &= StringRight(' ' &$aAllDaysInMonth[$j][$k][$iSideBySide*$n+$i-1],$iRight)				Next				If $i <$iSideBySide Then $sLine &=$sSpace			Next			_PrintLine($sLine) Next NextEndFunc ;==>_CreateCalendar Func _PrintLine($_sLine, $_sLF='') Local$iLen = StringLen($_sLine) Local$sSpace = '', $sLeft = '' For$i = 1 To $iPrintSize-1$sSpace &= ' '	Next	If $iLen <$iPrintSize Then $sLeft = StringLeft($sSpace, Int(($iPrintSize-$iLen)/2))	ConsoleWrite($sLeft &$_sLine & $_sLF & @LF)EndFunc ;==>_PrintLine  Output  [ here is Snoopy ] 1 9 6 9 January February March Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 6 7 8 9 10 11 12 3 4 5 6 7 8 9 3 4 5 6 7 8 9 13 14 15 16 17 18 19 10 11 12 13 14 15 16 10 11 12 13 14 15 16 20 21 22 23 24 25 26 17 18 19 20 21 22 23 17 18 19 20 21 22 23 27 28 29 30 31 24 25 26 27 28 24 25 26 27 28 29 30 31 April May June Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 4 1 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 30 July August September Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 1 2 3 4 5 6 7 7 8 9 10 11 12 13 4 5 6 7 8 9 10 8 9 10 11 12 13 14 14 15 16 17 18 19 20 11 12 13 14 15 16 17 15 16 17 18 19 20 21 21 22 23 24 25 26 27 18 19 20 21 22 23 24 22 23 24 25 26 27 28 28 29 30 31 25 26 27 28 29 30 31 29 30 October November December Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 3 4 5 6 7 6 7 8 9 10 11 12 3 4 5 6 7 8 9 8 9 10 11 12 13 14 13 14 15 16 17 18 19 10 11 12 13 14 15 16 15 16 17 18 19 20 21 20 21 22 23 24 25 26 17 18 19 20 21 22 23 22 23 24 25 26 27 28 27 28 29 30 31 24 25 26 27 28 29 30 29 30 31  --BugFix (talk) 00:40, 15 November 2013 (UTC) ## AWK  Works with Gnu awk version 3.1.5 and with BusyBox v1.20.0.git awkTo change the output width, change the value assigned to variable pagewide #!/bin/gawk -fBEGIN{ wkdays = "Su Mo Tu We Th Fr Sa" pagewide = 80 blank=" " for (i=1; i<pagewide; i++) blank = blank " " # month name accessed as substr(month,num*10,10) # where num is number of month, 1-12 month= " January February March April " month= month " May June July August " month= month " September October November December " # table of days per month accessed as substr(days,2*month,2) days =" 312831303130313130313031" line1 = "" line2 = "" line3 = "" line4 = "" line5 = "" line6 = "" line7 = "" line8 = ""# print " year: " year " starts on: " dow(year) }function center(text, half) { half = (pagewide - length(text))/2 return substr(blank,1,half) text substr(blank,1,half) }function min(a,b) { if (a < b) return a else return b }function makewk (fst,lst,day, i,wstring ){ wstring="" for (i=1;i<day;i++) wstring=wstring " " for (i=fst;i<=lst;i++) wstring=wstring sprintf("%2d ",i) return substr(wstring " ",1,20) }function dow (year, y){ y=year y= (y*365+int(y/4) - int(y/100) + int(y/400) +1) %7# leap year adjustment leap = 0 if (year % 4 == 0) leap = 1 if (year % 100 == 0) leap = 0 if (year % 400 == 0) leap = 1 y = y - leap if (y==-1) y=6 if (y==0) y=7 return (y) }function prmonth (nmonth, newdow,monsize ){ line1 = line1 " " (substr(month,10*nmonth,10)) " " line2 = line2 (wkdays) " " line3 = line3 (makewk(1,8-newdow,newdow)) " " line4 = line4 (makewk(9-newdow,15-newdow,1)) " " line5 = line5 (makewk(16-newdow,22-newdow,1)) " " line6 = line6 (makewk(23-newdow,29-newdow,1)) " " line7 = line7 (makewk(30-newdow,min(monsize,36-newdow),1)) " " line8 = line8 (makewk(37-newdow,monsize,1)) " "if (length(line3) + 22 > pagewide) { print center(line1) print center(line2) print center(line3) print center(line4) print center(line5) print center(line6) print center(line7) print center(line8) line1 = "" line2 = "" line3 = "" line4 = "" line5 = "" line6 = "" line7 = "" line8 = "" }}/q/{ exit }{ monsize=substr(days,2*1,2) newdow=dow($1)  print center("[ picture of Snoopy goes here ]")  print center(sprintf("%d",$1) ) # January - December for (i=1; i<13; i++) { prmonth(i,newdow,monsize) newdow=(monsize+newdow) %7 if (newdow == 0) newdow = 7 monsize=substr(days,2+2*i,2) if (leap == 1 && monsize == 28) monsize = 29 } }  Output:  [ picture of Snoopy goes here ] 1969 January February March Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 30 31 April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 27 28 29 30 25 26 27 28 29 30 31 29 30 July August September Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 31 October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 30  ## Batch File ::Calender Task from Rosetta Code Wiki::Batch File Implementation @echo offsetlocal enabledelayedexpansion %== Set a valid year [will not be validated] ==%set y=1969 %== Set the variables for months (feb_l=the normal 28 days) ==%set jan_l=31&set apr_l=30set mar_l=31&set jun_l=30set may_l=31&set sep_l=30set jul_l=31&set nov_l=30set aug_l=31&set feb_l=28set oct_l=31set dec_l=31 %== Compute day for first day of the year ==%set /a d=(y/4+y)-(y/100-y/400) %== Check if that year is a leap year ==%set /a "op1=y%%4","op2=y%%100","op3=y%%400"if not "%op1%"=="0" (goto :no_leap)if not "%op2%"=="0" (goto :yes_leap)if not "%op3%"=="0" (goto :no_leap) :yes_leap %== Ooops... Leap year. Change feb_l to 29. ==% set feb_l=29 set/a d-=1 :no_leap %== Compute weekday of the first day... ==%set /a d%%=7 %== Generate everything that's inside the calendar ==%for %%a in (jan feb mar apr may jun jul aug sep oct nov dec) do ( set %%a= set chars_added=0 for /l %%b in (1,1,!d!) do (set "%%a=!%%a! "&set /a chars_added+=3) for /l %%c in (1,1,!%%a_l!) do ( if %%c lss 10 (set "%%a=!%%a! %%c ") else (set "%%a=!%%a!%%c ") set /a chars_added+=3 ) for /l %%d in (!chars_added!,1,124) do set "%%a=!%%a! " set /a d=^(d+%%a_l^)%%7) %== Display the calendar ==%clsecho.echo. [SNOOPY]echo. echo. YEAR = %y%echo.echo. January February Marchecho. Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa echo. %jan:~0,20% %feb:~0,20% %mar:~0,20%echo. %jan:~21,20% %feb:~21,20% %mar:~21,20%echo. %jan:~42,20% %feb:~42,20% %mar:~42,20%echo. %jan:~63,20% %feb:~63,20% %mar:~63,20%echo. %jan:~84,20% %feb:~84,20% %mar:~84,20%echo. %jan:~105% %feb:~105% %mar:~105%echo.echo. April May Juneecho. Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa echo. %apr:~0,20% %may:~0,20% %jun:~0,20%echo. %apr:~21,20% %may:~21,20% %jun:~21,20%echo. %apr:~42,20% %may:~42,20% %jun:~42,20%echo. %apr:~63,20% %may:~63,20% %jun:~63,20%echo. %apr:~84,20% %may:~84,20% %jun:~84,20%echo. %apr:~105% %may:~105% %jun:~105%echo.echo. July August Septemberecho. Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa echo. %jul:~0,20% %aug:~0,20% %sep:~0,20%echo. %jul:~21,20% %aug:~21,20% %sep:~21,20%echo. %jul:~42,20% %aug:~42,20% %sep:~42,20%echo. %jul:~63,20% %aug:~63,20% %sep:~63,20%echo. %jul:~84,20% %aug:~84,20% %sep:~84,20%echo. %jul:~105% %aug:~105% %sep:~105%echo.echo. October November Decemberecho. Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa echo. %oct:~0,20% %nov:~0,20% %dec:~0,20%echo. %oct:~21,20% %nov:~21,20% %dec:~21,20%echo. %oct:~42,20% %nov:~42,20% %dec:~42,20%echo. %oct:~63,20% %nov:~63,20% %dec:~63,20%echo. %oct:~84,20% %nov:~84,20% %dec:~84,20%echo. %oct:~105% %nov:~105% %dec:~105%echo.pauseendlocal Output:  [SNOOPY] YEAR = 1969 January February March Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 30 31 April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 27 28 29 30 25 26 27 28 29 30 31 29 30 July August September Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 31 October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 30 Press any key to continue . . . ## BBC BASIC The day and month names are in the language for which the PC is configured.  INSTALL @lib$+"DATELIB"      VDU 23,22,640;570;8,15,16,128       year% = 1969      PRINT TAB(38); year%      DIM dom%(2), mjd%(2), dim%(2)       FOR day% = 1 TO 7        days$+= LEFT$(FN_date$(FN_mjd(day%, 1, 1905), "ddd"), 2) + " " NEXT FOR month% = 1 TO 10 STEP 3 PRINT FOR col% = 0 TO 2 mjd%(col%) = FN_mjd(1, month% + col%, year%) month$ = FN_date$(mjd%(col%), "MMMM") PRINT TAB(col%*24 + 16 - LEN(month$)/2) month$; NEXT FOR col% = 0 TO 2 PRINT TAB(col%*24 + 6) days$;          dim%(col%) = FN_dim(month% + col%, year%)        NEXT        dom%() = 1        col% = 0        REPEAT          dow% = FN_dow(mjd%(col%))          IF dom%(col%)<=dim%(col%) THEN            PRINT TAB(col%*24 + dow%*3 + 6); dom%(col%);            dom%(col%) += 1            mjd%(col%) += 1          ENDIF          IF dow%=6 OR dom%(col%)>dim%(col%) col% = (col% + 1) MOD 3        UNTIL dom%(0)>dim%(0) AND dom%(1)>dim%(1) AND dom%(2)>dim%(2)        PRINT      NEXT

Output:

                                      1969

January                 February                 March
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1                       1
5  6  7  8  9  10 11    2  3  4  5  6  7  8     2  3  4  5  6  7  8
12 13 14 15 16 17 18    9  10 11 12 13 14 15    9  10 11 12 13 14 15
19 20 21 22 23 24 25    16 17 18 19 20 21 22    16 17 18 19 20 21 22
26 27 28 29 30 31       23 24 25 26 27 28       23 24 25 26 27 28 29
30 31

April                    May                     June
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                 1  2  3     1  2  3  4  5  6  7
6  7  8  9  10 11 12    4  5  6  7  8  9  10    8  9  10 11 12 13 14
13 14 15 16 17 18 19    11 12 13 14 15 16 17    15 16 17 18 19 20 21
20 21 22 23 24 25 26    18 19 20 21 22 23 24    22 23 24 25 26 27 28
27 28 29 30             25 26 27 28 29 30 31    29 30

July                   August                September
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                    1  2        1  2  3  4  5  6
6  7  8  9  10 11 12    3  4  5  6  7  8  9     7  8  9  10 11 12 13
13 14 15 16 17 18 19    10 11 12 13 14 15 16    14 15 16 17 18 19 20
20 21 22 23 24 25 26    17 18 19 20 21 22 23    21 22 23 24 25 26 27
27 28 29 30 31          24 25 26 27 28 29 30    28 29 30
31

October                 November                December
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1        1  2  3  4  5  6
5  6  7  8  9  10 11    2  3  4  5  6  7  8     7  8  9  10 11 12 13
12 13 14 15 16 17 18    9  10 11 12 13 14 15    14 15 16 17 18 19 20
19 20 21 22 23 24 25    16 17 18 19 20 21 22    21 22 23 24 25 26 27
26 27 28 29 30 31       23 24 25 26 27 28 29    28 29 30 31
30

## Befunge

This is quite closely based on the C sample, although the centering calculation has been adjusted to fix an off-by-one error, and the months have been made a constant height, regardless of how much space they require, to try and produce a more balanced layout.

The year is read from stdin, and the width is specified by the first value on the stack (set to 80 - "P" - in the current implementation).

"P"00p&>:::4%!\"d"%*\45*:*%!+!!65*+31p:1-:::"I"5**\4/+\"d"/-\45*:*/+1+7%:0vJ!F?M!A M!J J!A!S O!N D!SaFrThWeTuMoSuvp01:_1#!-#%:#\>#+6<v-2g1+1g01p1p01:< January  February  March    April    >:45**00g\-\1-:v:<<6>+7%:10g2+:38*\|   May      June     July    August v02-1:+4*-4\\4:/_$:^^:/*2+92+2:g00$$<September October November December>p:45*+10g*\--2/00g4-2/>:#,1#*-#8\#4_v>20g>:#,1#*-#8\#4_6"S" v. .vp040\_4#!8#\*#-,#1>#:<+5g03g01:,,:+55<0.p03<^_v#:-1_v#!:,*84,g1+1,< < ^ >::4%9*40g:8!#v_$$$1+v^+g02_#v$#,$#+5<^_v#\<-#8\#4_$7>1-:2*64*+:1g>^ ^ ^,g+2/4\+p04+1:<>1#\-#<:66+\^ >>$10g30g>:#,1#*> > $$55+,6>>40p:10g30g>:#,1#*-#8\#4_>\:2*:1+1g2-50p1g640g-7*1+\-7v v@,<62:+g01_55+,^ > > > > #^>#g>#0>#2_v v*2!!\%+55:\/+55:**0\!g05:::\< >2-^^->:> >#^>#<>#<^#!:-1g04$$ < < < < < >4+8*+\:!!2*4+8*+,,48*,1+\1-:>#^_1+\1

## C

With arbitrary display width (>= 20 though) and auto spacing.

#include <stdio.h>#include <stdlib.h>#include <string.h> int width = 80, year = 1969;int cols, lead, gap; const char *wdays[] = { "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa" };struct months {	const char *name;	int days, start_wday, at;} months[12] = {	{ "January",	31, 0, 0 },	{ "Februray",	28, 0, 0 },	{ "March",	31, 0, 0 },	{ "April",	30, 0, 0 },	{ "May",	31, 0, 0 },	{ "June",	30, 0, 0 },	{ "July",	31, 0, 0 },	{ "August",	31, 0, 0 },	{ "September",	30, 0, 0 },	{ "October",	31, 0, 0 },	{ "November",	30, 0, 0 },	{ "December",	31, 0, 0 }}; void space(int n) { while (n-- > 0) putchar(' '); } void init_months(){	int i; 	if ((!(year % 4) && (year % 100)) || !(year % 400))		months[1].days = 29; 	year--;	months[0].start_wday		= (year * 365 + year/4 - year/100 + year/400 + 1) % 7; 	for (i = 1; i < 12; i++)		months[i].start_wday =			(months[i-1].start_wday + months[i-1].days) % 7; 	cols = (width + 2) / 22;	while (12 % cols) cols--;	gap = cols - 1 ? (width - 20 * cols) / (cols - 1) : 0;	if (gap > 4) gap = 4;	lead = (width - (20 + gap) * cols + gap + 1) / 2;        year++;} void print_row(int row){	int c, i, from = row * cols, to = from + cols;	space(lead);	for (c = from; c < to; c++) {		i = strlen(months[c].name);		space((20 - i)/2);		printf("%s", months[c].name);		space(20 - i - (20 - i)/2 + ((c == to - 1) ? 0 : gap));	}	putchar('\n'); 	space(lead);	for (c = from; c < to; c++) {		for (i = 0; i < 7; i++)			printf("%s%s", wdays[i], i == 6 ? "" : " ");		if (c < to - 1) space(gap);		else putchar('\n');	} 	while (1) {		for (c = from; c < to; c++)			if (months[c].at < months[c].days) break;		if (c == to) break; 		space(lead);		for (c = from; c < to; c++) {			for (i = 0; i < months[c].start_wday; i++) space(3);			while(i++ < 7 && months[c].at < months[c].days) {				printf("%2d", ++months[c].at);				if (i < 7 || c < to - 1) putchar(' ');			}			while (i++ <= 7 && c < to - 1) space(3);			if (c < to - 1) space(gap - 1);			months[c].start_wday = 0;		}		putchar('\n');	}	putchar('\n');} void print_year(){	int row;	char buf[32];	sprintf(buf, "%d", year);	space((width - strlen(buf)) / 2);	printf("%s\n\n", buf);	for (row = 0; row * cols < 12; row++)		print_row(row);} int main(int c, char **v){	int i, year_set = 0;	for (i = 1; i < c; i++) {		if (!strcmp(v[i], "-w")) {			if (++i == c || (width = atoi(v[i])) < 20)				goto bail;		} else if (!year_set) {			if (!sscanf(v[i], "%d", &year) || year <= 0)				year = 1969;			year_set = 1;		} else			goto bail;	} 	init_months();	print_year();	return 0; bail:	fprintf(stderr, "bad args\nUsage: %s year [-w width (>= 20)]\n", v[0]);	exit(1);}

## C++

 #include <windows.h>#include <iostream> //--------------------------------------------------------------------------------------------------using namespace std;  //--------------------------------------------------------------------------------------------------class calender{public:    void drawCalender( int y )    {	year = y;	for( int i = 0; i < 12; i++ )	    firstdays[i] = getfirstday( i ); 	isleapyear();	build();    } private:    void isleapyear()    {	isleap = false; 	if( !( year % 4 ) )	{	    if( year % 100 ) isleap = true;	    else if( !( year % 400 ) ) isleap = true;	}    }     int getfirstday( int m )    {	int y = year; 	int f = y + 1 + 3 * m - 1;	m++;	if( m < 3 ) y--;	else f -= int( .4 * m + 2.3 ); 	f += int( y / 4 ) - int( ( y / 100 + 1 ) * 0.75 );	f %= 7; 	return f;    }     void build()    {	int days[] = { 31, isleap ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };	int lc = 0, lco = 0, ystr = 7, start = 2, fd = 0, m = 0;	HANDLE h = GetStdHandle( STD_OUTPUT_HANDLE );	COORD pos = { 0, ystr };	draw(); 	for( int i = 0; i < 4; i++ )	{	    for( int j = 0; j < 3; j++ )	    {		int d = firstdays[fd++], dm = days[m++];		pos.X = d * 3 + start;		SetConsoleCursorPosition( h, pos ); 		for( int dd = 0; dd < dm; dd++ )		{		    if( dd < 9 ) cout << 0 << dd + 1 << " ";		    else cout << dd + 1 << " "; 		    pos.X += 3;		    if( pos.X - start > 20 )		    {			pos.X = start; pos.Y++;			SetConsoleCursorPosition( h, pos );		    }		} 		start += 23;		pos.X = start; pos.Y = ystr;		SetConsoleCursorPosition( h, pos );	    }	    ystr += 9; start = 2;	    pos.Y = ystr;	}    }     void draw()    {	system( "cls" );	cout << "+--------------------------------------------------------------------+" << endl;	cout << "|                              [SNOOPY]                              |" << endl;	cout << "|                                                                    |" << endl;	cout << "|                             == " << year << " ==                             |" << endl;	cout << "+----------------------+----------------------+----------------------+" << endl;	cout << "|       JANUARY        |       FEBRUARY       |         MARCH        |" << endl;	cout << "| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "+----------------------+----------------------+----------------------+" << endl;	cout << "|        APRIL         |          MAY         |         JUNE         |" << endl;	cout << "| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "+----------------------+----------------------+----------------------+" << endl;	cout << "|         JULY         |        AUGUST        |       SEPTEMBER      |" << endl;	cout << "| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "+----------------------+----------------------+----------------------+" << endl;	cout << "|        OCTOBER       |       NOVEMBER       |       DECEMBER       |" << endl;	cout << "| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "|                      |                      |                      |" << endl;	cout << "+----------------------+----------------------+----------------------+" << endl;    }     int firstdays[12], year;    bool isleap;};//--------------------------------------------------------------------------------------------------int main( int argc, char* argv[] ){    int y;    calender cal;     while( true )    {	system( "cls" );	cout << "Enter the year( yyyy ) --- ( 0 to quit ): "; 	cin >> y;	if( !y ) return 0; 	cal.drawCalender( y );	cout << endl << endl << endl << endl << endl << endl << endl << endl; 	system( "pause" );    }    return 0;}//--------------------------------------------------------------------------------------------------

Output:

+--------------------------------------------------------------------+
|                              [SNOOPY]                              |
|                                                                    |
|                             == 1969 ==                             |
+----------------------+----------------------+----------------------+
|       JANUARY        |       FEBRUARY       |         MARCH        |
| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |
|          01 02 03 04 |                   01 |                   01 |
| 05 06 07 08 09 10 11 | 02 03 04 05 06 07 08 | 02 03 04 05 06 07 08 |
| 12 13 14 15 16 17 18 | 09 10 11 12 13 14 15 | 09 10 11 12 13 14 15 |
| 19 20 21 22 23 24 25 | 16 17 18 19 20 21 22 | 16 17 18 19 20 21 22 |
| 26 27 28 29 30 31    | 23 24 25 26 27 28    | 23 24 25 26 27 28 29 |
|                      |                      | 30 31                |
+----------------------+----------------------+----------------------+
|        APRIL         |          MAY         |         JUNE         |
| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |
|       01 02 03 04 05 |             01 02 03 | 01 02 03 04 05 06 07 |
| 06 07 08 09 10 11 12 | 04 05 06 07 08 09 10 | 08 09 10 11 12 13 14 |
| 13 14 15 16 17 18 19 | 11 12 13 14 15 16 17 | 15 16 17 18 19 20 21 |
| 20 21 22 23 24 25 26 | 18 19 20 21 22 23 24 | 22 23 24 25 26 27 28 |
| 27 28 29 30          | 25 26 27 28 29 30 31 | 29 30                |
|                      |                      |                      |
+----------------------+----------------------+----------------------+
|         JULY         |        AUGUST        |       SEPTEMBER      |
| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |
|       01 02 03 04 05 |                01 02 |    01 02 03 04 05 06 |
| 06 07 08 09 10 11 12 | 03 04 05 06 07 08 09 | 07 08 09 10 11 12 13 |
| 13 14 15 16 17 18 19 | 10 11 12 13 14 15 16 | 14 15 16 17 18 19 20 |
| 20 21 22 23 24 25 26 | 17 18 19 20 21 22 23 | 21 22 23 24 25 26 27 |
| 27 28 29 30 31       | 24 25 26 27 28 29 30 | 28 29 30             |
|                      | 31                   |                      |
+----------------------+----------------------+----------------------+
|        OCTOBER       |       NOVEMBER       |       DECEMBER       |
| SU MO TU WE TH FR SA | SU MO TU WE TH FR SA | SU MO TU WE TH FR SA |
|          01 02 03 04 |                   01 |    01 02 03 04 05 06 |
| 05 06 07 08 09 10 11 | 02 03 04 05 06 07 08 | 07 08 09 10 11 12 13 |
| 12 13 14 15 16 17 18 | 09 10 11 12 13 14 15 | 14 15 16 17 18 19 20 |
| 19 20 21 22 23 24 25 | 16 17 18 19 20 21 22 | 21 22 23 24 25 26 27 |
| 26 27 28 29 30 31    | 23 24 25 26 27 28 29 | 28 29 30 31          |
|                      | 30                   |                      |
+----------------------+----------------------+----------------------+


## C#

An attempt to abuse the DateTime class for all static information. In the event that the number of days and months changes, so long as the DateTime class is updated accordingly, this should still print properly. It also abuses iterators to allow for a concise month printing method, but with the ability to still print x months per line.

  using System;using System.Collections.Generic; using System.Linq;using System.Text; namespace CalendarStuff{     class Program    {        static void Main(string[] args)        {            Console.WindowHeight = 46;            Console.Write(buildMonths(new DateTime(1969, 1, 1)));            Console.Read();         }        private static string buildMonths(DateTime date)        {            StringBuilder sb = new StringBuilder();            sb.AppendLine(center("[Snoop]", 24 * 3));            sb.AppendLine();            sb.AppendLine(center(date.Year.ToString(), 24 * 3));             List<DateTime> dts = new List<DateTime>();            while (true)            {                dts.Add(date);                if (date.Year != ((date = date.AddMonths(1)).Year))                {                    break;                }            }            var jd = dts.Select(a => buildMonth(a).GetEnumerator()).ToArray();             int sCur=0;            while (sCur<dts.Count)            {                sb.AppendLine();                int curMonth=0;                 var j = jd.Where(a => curMonth++ >= sCur && curMonth - 1 < sCur + 3).ToArray(); //grab the next 3                sCur += j.Length;                 bool breakOut = false;                while (!breakOut)                {                    int inj = 1;                    foreach (var cd in j)                    {                        if (cd.MoveNext())                        {                            sb.Append((cd.Current.Length == 21 ? cd.Current : cd.Current.PadRight(21, ' ')) + "     ");                        }                        else                        {                            sb.Append("".PadRight(21, ' ') + "     ");                            breakOut = true;                        }                        if (inj++ % 3 == 0) sb.AppendLine();                    }                }             }            return sb.ToString();        }          private static IEnumerable<string> buildMonth(DateTime date)        {            yield return center(date.ToString("MMMM"),7*3);            var j = DateTime.DaysInMonth(date.Year, date.Month);            yield return Enum.GetNames(typeof(DayOfWeek)).Aggregate("", (current, result) => current + (result.Substring(0, 2).ToUpper() + " "));            string cur = "";            int total = 0;             foreach (var day in Enumerable.Range(-((int)date.DayOfWeek),j + (int)date.DayOfWeek))            {                cur += (day < 0 ? "  " : ((day < 9 ? " " : "") + (day + 1))) +" ";                if (total++ > 0 && (total ) % 7 == 0)                {                    yield return cur;                    cur = "";                }            }            yield return cur;        }        private static string center(string s, int len)        {            return (s.PadLeft((len - s.Length) / 2 + s.Length, ' ').PadRight((len), ' '));        }     }}

## COBOL

the program calls subroutine DATE2DOW to convert any YYYY-MM-DD to Day of Week (1=Sunday). the group names WS-CFGN and WS-CFGW may be moved to WS-CFG to use narrow or wide print line size respectively.

        IDENTIFICATION DIVISION.       PROGRAM-ID.  CALEND.       ENVIRONMENT DIVISION.       INPUT-OUTPUT SECTION.       DATA DIVISION.        WORKING-STORAGE SECTION.       01  WS-DAY-NAMES-DEF.         03 FILLER PIC X(09) VALUE 'SUNDAY   '.         03 FILLER PIC X(09) VALUE 'MONDAY   '.         03 FILLER PIC X(09) VALUE 'TUESDAY  '.         03 FILLER PIC X(09) VALUE 'WEDNESDAY'.         03 FILLER PIC X(09) VALUE 'THURSDAY '.         03 FILLER PIC X(09) VALUE 'FRIDAY   '.         03 FILLER PIC X(09) VALUE 'SATURDAY '.       01  FILLER REDEFINES WS-DAY-NAMES-DEF.         03  WS-DAY-NAME       PIC X(09) OCCURS 07 TIMES.        01  WS-MTH-INFO-DEF.         03 FILLER PIC X(11) VALUE 'JANUARY  31'.         03 FILLER PIC X(11) VALUE 'FEBRUARY 28'.         03 FILLER PIC X(11) VALUE 'MARCH    31'.         03 FILLER PIC X(11) VALUE 'APRIL    30'.         03 FILLER PIC X(11) VALUE 'MAY      31'.         03 FILLER PIC X(11) VALUE 'JUNE     30'.         03 FILLER PIC X(11) VALUE 'JULY     31'.         03 FILLER PIC X(11) VALUE 'AUGUST   31'.         03 FILLER PIC X(11) VALUE 'SEPTEMBER30'.         03 FILLER PIC X(11) VALUE 'OCTOBER  31'.         03 FILLER PIC X(11) VALUE 'NOVEMBER 30'.         03 FILLER PIC X(11) VALUE 'DECEMBER 31'.       01  FILLER REDEFINES WS-MTH-INFO-DEF.         03  WS-MTH-INFO-TABLE OCCURS 12 TIMES.           05  WS-MTH-INFO-NAME   PIC X(09).           05  WS-MTH-INFO-DAYS   PIC 9(02).        01  WS-MTH-AREA.         03  WS-MTH-DD         PIC S99.         03  WS-DAY1           PIC   9.         03  WS-DAYS           PIC  99.         03  WS-DD             PIC   9.         03  WS-WK             PIC   9.         03  WS-MM             PIC  99.         03  WS-QQ             PIC  99.          03  WS-MTH-MONTH  OCCURS 12 TIMES.           05  WS-MTH-WEEK OCCURS 6 TIMES.             07  WS-DAY-FLD      OCCURS 7 TIMES.               09  WS-DAY        PIC ZZ.       01  INPDATE-RECORD.           05  INPD-YEAR          PIC 9(04).           05  FILLER             PIC X(01).           05  INPD-MONTH         PIC 9(02).           05  FILLER             PIC X(01).           05  INPD-DAY           PIC 9(02).       01  WMS-DOW                PIC 9(01).       01  WS-PRT                 PIC X(132).       01  WS-COL                 PIC  9(03) VALUE 0.       01  WS-PP                  PIC  9(03) VALUE 0.       01  WS-CFGN.         03  FILLER               PIC  9(03) VALUE  80.         03  FILLER               PIC  9(02) VALUE  5.         03  FILLER               PIC  9(01) VALUE  1.         03  FILLER               PIC  9(02) VALUE  5.         03  FILLER               PIC  9(01) VALUE  2.       01  WS-CFGW.         03  FILLER               PIC  9(03) VALUE 120.         03  FILLER               PIC  9(02) VALUE 10.         03  FILLER               PIC  9(01) VALUE  2.         03  FILLER               PIC  9(02) VALUE 10.         03  FILLER               PIC  9(01) VALUE  3.       01  WS-CFG.         03  WS-LS                PIC  9(03) VALUE 120.         03  WS-LMAR              PIC  9(02) VALUE 10.         03  WS-SPBD              PIC  9(01) VALUE  2.         03  WS-SPBC              PIC  9(02) VALUE 10.         03  WS-DNMW              PIC  9(01) VALUE  3.       PROCEDURE DIVISION.           MOVE '1969-01-01' TO INPDATE-RECORD           MOVE WS-CFGN   TO WS-CFG           IF  (FUNCTION MOD ( INPD-YEAR , 400 ) = 0           OR  (FUNCTION MOD ( INPD-YEAR , 4   ) = 0               AND               FUNCTION MOD ( INPD-YEAR , 100 ) NOT = 0))             MOVE 29         TO WS-MTH-INFO-DAYS (02)           ELSE             MOVE 28         TO WS-MTH-INFO-DAYS (02)           END-IF            PERFORM VARYING WS-MM FROM 1 BY +1           UNTIL WS-MM > 12           MOVE WS-MM TO INPD-MONTH           CALL 'DATE2DOW' USING INPDATE-RECORD, WMS-DOW           COMPUTE WS-MTH-DD = 1 - WMS-DOW           COMPUTE WS-DAYS = WS-MTH-INFO-DAYS (INPD-MONTH)           PERFORM VARYING WS-WK FROM 1 BY +1           UNTIL WS-WK > 6             PERFORM VARYING WS-DD FROM 1 BY +1             UNTIL WS-DD > 7               COMPUTE WS-MTH-DD = WS-MTH-DD + 1               IF (WS-MTH-DD < 1)               OR (WS-MTH-DD > WS-DAYS)                 MOVE 0         TO WS-DAY (WS-MM, WS-WK, WS-DD)               ELSE                 MOVE WS-MTH-DD TO WS-DAY (WS-MM, WS-WK, WS-DD)               END-IF             END-PERFORM           END-PERFORM           END-PERFORM            COMPUTE WS-MM = 0           PERFORM VARYING WS-QQ FROM 1 BY +1           UNTIL WS-QQ > 4              INITIALIZE WS-PRT             COMPUTE WS-PP = 1             PERFORM VARYING WS-COL FROM 1 BY +1             UNTIL WS-COL > 3             COMPUTE WS-MM = 3 * (WS-QQ - 1) + WS-COL                IF WS-COL = 1                 COMPUTE WS-PP = WS-PP + WS-LMAR + 2 - WS-DNMW               ELSE                 COMPUTE WS-PP = WS-PP + WS-SPBC + 2 - WS-DNMW               END-IF               MOVE WS-MTH-INFO-NAME (WS-MM)                             TO WS-PRT(WS-PP:9)               COMPUTE WS-PP               =       WS-PP + ( 2 * 7 + WS-SPBD * 6 + WS-SPBD - 1)               -       4               MOVE INPD-YEAR TO WS-PRT (WS-PP:4)               COMPUTE WS-PP = WS-PP + 4             END-PERFORM             DISPLAY WS-PRT (1:WS-LS)              INITIALIZE WS-PRT             COMPUTE WS-PP = 1             PERFORM VARYING WS-COL FROM 1 BY +1             UNTIL WS-COL > 3             COMPUTE WS-MM = 3 * (WS-QQ - 1) + WS-COL                IF WS-COL = 1                 COMPUTE WS-PP = WS-PP + WS-LMAR + 2 - WS-DNMW               ELSE                 COMPUTE WS-PP = WS-PP + WS-SPBC + 2 - WS-DNMW               END-IF               PERFORM VARYING WS-DD FROM 1 BY +1               UNTIL WS-DD > 7                 IF WS-DD > 1                   COMPUTE WS-PP = WS-PP + WS-SPBD + 2 - WS-DNMW                 END-IF                 MOVE WS-DAY-NAME (WS-DD) (1:WS-DNMW)                             TO WS-PRT (WS-PP:WS-DNMW)                 COMPUTE WS-PP = WS-PP + WS-DNMW               END-PERFORM             END-PERFORM             DISPLAY WS-PRT (1:WS-LS)              PERFORM VARYING WS-WK FROM 1 BY +1             UNTIL WS-WK > 6               INITIALIZE WS-PRT               COMPUTE WS-PP = 1               PERFORM VARYING WS-COL FROM 1 BY +1               UNTIL WS-COL > 3               COMPUTE WS-MM = 3 * (WS-QQ - 1) + WS-COL                  IF WS-COL = 1                   COMPUTE WS-PP = WS-PP + WS-LMAR                 ELSE                   COMPUTE WS-PP = WS-PP + WS-SPBC                 END-IF                 PERFORM VARYING WS-DD FROM 1 BY +1                 UNTIL WS-DD > 7                   IF WS-DD > 1                     COMPUTE WS-PP = WS-PP + WS-SPBD                   END-IF                   MOVE WS-DAY (WS-MM, WS-WK, WS-DD)                               TO WS-PRT (WS-PP:2)                   COMPUTE WS-PP = WS-PP + 2                 END-PERFORM               END-PERFORM               DISPLAY WS-PRT (1:WS-LS)             END-PERFORM             DISPLAY ' '           END-PERFORM           GOBACK           .       END PROGRAM CALEND.       IDENTIFICATION DIVISION.       PROGRAM-ID.  DATE2DOW.       ENVIRONMENT DIVISION.       DATA DIVISION.       WORKING-STORAGE SECTION.       01  WMS-WORK-AREA.         03  WMS-YEAR       PIC 9(04).         03  WMS-MONTH      PIC 9(02).         03  WMS-CSYS       PIC 9(01) VALUE 1.         03  WMS-SUM        pic 9(04).       LINKAGE SECTION.       01  INPDATE-RECORD.           05  INPD-YEAR          PIC 9(04).           05  FILLER             PIC X(01).           05  INPD-MONTH         PIC 9(02).           05  FILLER             PIC X(01).           05  INPD-DAY           PIC 9(02).       01  WMS-DOW                PIC 9(01).       PROCEDURE DIVISION USING INPDATE-RECORD, WMS-DOW.       1010-CONVERT-DATE-TO-DOW.           IF INPD-MONTH < 3               COMPUTE WMS-MONTH = INPD-MONTH + 12               COMPUTE WMS-YEAR  = INPD-YEAR - 1           ELSE               COMPUTE WMS-MONTH = INPD-MONTH               COMPUTE WMS-YEAR  = INPD-YEAR           END-IF           COMPUTE WMS-SUM  =                             ( INPD-DAY + 2 * WMS-MONTH + WMS-YEAR                            + FUNCTION INTEGER (6 * (WMS-MONTH + 1) / 10)                            + FUNCTION INTEGER ( WMS-YEAR / 4   )                            - FUNCTION INTEGER ( WMS-YEAR / 100 )                            + FUNCTION INTEGER ( WMS-YEAR / 400 )                            + WMS-CSYS )           COMPUTE WMS-DOW = FUNCTION MOD (WMS-SUM, 7) + 1           GOBACK           .       END PROGRAM DATE2DOW.

Output (based on 80 character wide display)

     JANUARY         1969     FEBRUARY        1969     MARCH           1969
SU MO TU WE TH FR SA     SU MO TU WE TH FR SA     SU MO TU WE TH FR SA
1  2  3  4                        1                        1
5  6  7  8  9 10 11      2  3  4  5  6  7  8      2  3  4  5  6  7  8
12 13 14 15 16 17 18      9 10 11 12 13 14 15      9 10 11 12 13 14 15
19 20 21 22 23 24 25     16 17 18 19 20 21 22     16 17 18 19 20 21 22
26 27 28 29 30 31        23 24 25 26 27 28        23 24 25 26 27 28 29
30 31

APRIL           1969     MAY             1969     JUNE            1969
SU MO TU WE TH FR SA     SU MO TU WE TH FR SA     SU MO TU WE TH FR SA
1  2  3  4  5                  1  2  3      1  2  3  4  5  6  7
6  7  8  9 10 11 12      4  5  6  7  8  9 10      8  9 10 11 12 13 14
13 14 15 16 17 18 19     11 12 13 14 15 16 17     15 16 17 18 19 20 21
20 21 22 23 24 25 26     18 19 20 21 22 23 24     22 23 24 25 26 27 28
27 28 29 30              25 26 27 28 29 30 31     29 30

JULY            1969     AUGUST          1969     SEPTEMBER       1969
SU MO TU WE TH FR SA     SU MO TU WE TH FR SA     SU MO TU WE TH FR SA
1  2  3  4  5                     1  2         1  2  3  4  5  6
6  7  8  9 10 11 12      3  4  5  6  7  8  9      7  8  9 10 11 12 13
13 14 15 16 17 18 19     10 11 12 13 14 15 16     14 15 16 17 18 19 20
20 21 22 23 24 25 26     17 18 19 20 21 22 23     21 22 23 24 25 26 27
27 28 29 30 31           24 25 26 27 28 29 30     28 29 30
31

OCTOBER         1969     NOVEMBER        1969     DECEMBER        1969
SU MO TU WE TH FR SA     SU MO TU WE TH FR SA     SU MO TU WE TH FR SA
1  2  3  4                        1         1  2  3  4  5  6
5  6  7  8  9 10 11      2  3  4  5  6  7  8      7  8  9 10 11 12 13
12 13 14 15 16 17 18      9 10 11 12 13 14 15     14 15 16 17 18 19 20
19 20 21 22 23 24 25     16 17 18 19 20 21 22     21 22 23 24 25 26 27
26 27 28 29 30 31        23 24 25 26 27 28 29     28 29 30 31
30


## Common Lisp

Depends on quicklisp.

(ql:quickload '(date-calc)) (defparameter *day-row* "Su Mo Tu We Th Fr Sa")(defparameter *calendar-margin* 3) (defun month-to-word (month)  "Translate a MONTH from 1 to 12 into its word representation."  (svref #("January" "February" "March" "April"           "May" "June" "July" "August"           "September" "October" "November" "December")         (1- month))) (defun month-strings (year month)  "Collect all of the strings that make up a calendar for a givenMONTH and YEAR."  (,(date-calc:center (month-to-word month) (length *day-row*))     ,*day-row*     ;; We can assume that a month calendar will always fit into a 7 by 6 block     ;; of values. This makes it easy to format the resulting strings.     ,@ (let ((days (make-array (* 7 6) :initial-element nil)))          (loop :for i :from (date-calc:day-of-week year month 1)             :for day :from 1 :to (date-calc:days-in-month year month)             :do (setf (aref days i) day))          (loop :for i :from 0 :to 5             :collect             (format nil "~{~:[  ~;~2,d~]~^ ~}"                     (loop :for day :across (subseq days (* i 7) (+ 7 (* i 7)))                        :append (if day (list day day) (list day)))))))) (defun calc-columns (characters margin-size)  "Calculate the number of columns given the number of CHARACTERS percolumn and the MARGIN-SIZE between them."  (multiple-value-bind (cols excess)      (truncate characters (+ margin-size (length *day-row*)))    (incf excess margin-size)    (if (>= excess (length *day-row*))        (1+ cols)        cols))) (defun take (n list)  "Take the first N elements of a LIST."  (loop :repeat n :for x :in list :collect x)) (defun drop (n list)  "Drop the first N elements of a LIST."  (cond ((or (<= n 0) (null list)) list)        (t (drop (1- n) (cdr list))))) (defun chunks-of (n list)  "Split the LIST into chunks of size N."  (assert (> n 0))  (loop :for x := list :then (drop n x)     :while x     :collect (take n x))) (defun print-calendar (year &key (characters 80) (margin-size 3))  "Print out the calendar for a given YEAR, optionally specifyinga width limit in CHARACTERS and MARGIN-SIZE between months."  (assert (>= characters (length *day-row*)))  (assert (>= margin-size 0))  (let* ((calendars (loop :for month :from 1 :to 12                       :collect (month-strings year month)))         (column-count (calc-columns characters margin-size))         (total-size (+ (* column-count (length *day-row*))                        (* (1- column-count) margin-size)))         (format-string (concatenate 'string                                     "~{~a~^~" (write-to-string margin-size) ",0@T~}~%")))    (format t "~a~%~a~%~%"            (date-calc:center "[Snoopy]" total-size)            (date-calc:center (write-to-string year) total-size))    (loop :for row :in (chunks-of column-count calendars)       :do (apply 'mapcar                  (lambda (&rest heads)                    (format t format-string heads))                  row))))
Output:
CL-USER> (print-calendar 1969)
[Snoopy]
1969

January                February                March
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4                      1                      1
5  6  7  8  9 10 11    2  3  4  5  6  7  8    2  3  4  5  6  7  8
12 13 14 15 16 17 18    9 10 11 12 13 14 15    9 10 11 12 13 14 15
19 20 21 22 23 24 25   16 17 18 19 20 21 22   16 17 18 19 20 21 22
26 27 28 29 30 31      23 24 25 26 27 28      23 24 25 26 27 28 29
30 31
April                   May                    June
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5                1  2  3
6  7  8  9 10 11 12    4  5  6  7  8  9 10    1  2  3  4  5  6  7
13 14 15 16 17 18 19   11 12 13 14 15 16 17    8  9 10 11 12 13 14
20 21 22 23 24 25 26   18 19 20 21 22 23 24   15 16 17 18 19 20 21
27 28 29 30            25 26 27 28 29 30 31   22 23 24 25 26 27 28
29 30
July                  August               September
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5                   1  2       1  2  3  4  5  6
6  7  8  9 10 11 12    3  4  5  6  7  8  9    7  8  9 10 11 12 13
13 14 15 16 17 18 19   10 11 12 13 14 15 16   14 15 16 17 18 19 20
20 21 22 23 24 25 26   17 18 19 20 21 22 23   21 22 23 24 25 26 27
27 28 29 30 31         24 25 26 27 28 29 30   28 29 30
31
October                November               December
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4                      1       1  2  3  4  5  6
5  6  7  8  9 10 11    2  3  4  5  6  7  8    7  8  9 10 11 12 13
12 13 14 15 16 17 18    9 10 11 12 13 14 15   14 15 16 17 18 19 20
19 20 21 22 23 24 25   16 17 18 19 20 21 22   21 22 23 24 25 26 27
26 27 28 29 30 31      23 24 25 26 27 28 29   28 29 30 31
30
NIL

## D

import std.stdio, std.datetime, std.string, std.conv; void printCalendar(in uint year, in uint nCols)in {    assert(nCols > 0 && nCols <= 12);} body {    immutable rows = 12 / nCols + (12 % nCols != 0);    auto date = Date(year, 1, 1);    int offs = date.dayOfWeek;    const months = "January February March April May June        July August September October November December".split;     string[8][12] mons;    foreach (immutable m; 0 .. 12) {        mons[m][0] = months[m].center(21);        mons[m][1] = " Su Mo Tu We Th Fr Sa";        immutable dim = date.daysInMonth;        foreach (immutable d; 1 .. 43) {            immutable day = d > offs && d <= offs + dim;            immutable str = day ? format(" %2s", d-offs) : "   ";            mons[m][2 + (d - 1) / 7] ~= str;        }        offs = (offs + dim) % 7;        date.add!"months"(1);    }     "[Snoopy Picture]".center(nCols * 24 + 4).writeln;    writeln(year.text.center(nCols * 24 + 4), "\n");    foreach (immutable r; 0 .. rows) {        string[8] s;        foreach (immutable c; 0 .. nCols) {            if (r * nCols + c > 11)                break;            foreach (immutable i, line; mons[r * nCols + c])                s[i] ~= format("   %s", line);        }        writefln("%-(%s\n%)\n", s);    }} void main() {    printCalendar(1969, 3);}
                              [Snoopy Picture]
1969

January                February                  March
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1                       1
5  6  7  8  9 10 11     2  3  4  5  6  7  8     2  3  4  5  6  7  8
12 13 14 15 16 17 18     9 10 11 12 13 14 15     9 10 11 12 13 14 15
19 20 21 22 23 24 25    16 17 18 19 20 21 22    16 17 18 19 20 21 22
26 27 28 29 30 31       23 24 25 26 27 28       23 24 25 26 27 28 29
30 31

April                    May                    June
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                 1  2  3     1  2  3  4  5  6  7
6  7  8  9 10 11 12     4  5  6  7  8  9 10     8  9 10 11 12 13 14
13 14 15 16 17 18 19    11 12 13 14 15 16 17    15 16 17 18 19 20 21
20 21 22 23 24 25 26    18 19 20 21 22 23 24    22 23 24 25 26 27 28
27 28 29 30             25 26 27 28 29 30 31    29 30

July                   August                 September
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4  5                    1  2        1  2  3  4  5  6
6  7  8  9 10 11 12     3  4  5  6  7  8  9     7  8  9 10 11 12 13
13 14 15 16 17 18 19    10 11 12 13 14 15 16    14 15 16 17 18 19 20
20 21 22 23 24 25 26    17 18 19 20 21 22 23    21 22 23 24 25 26 27
27 28 29 30 31          24 25 26 27 28 29 30    28 29 30
31

October                November                December
Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa    Su Mo Tu We Th Fr Sa
1  2  3  4                       1        1  2  3  4  5  6
5  6  7  8  9 10 11     2  3  4  5  6  7  8     7  8  9 10 11 12 13
12 13 14 15 16 17 18     9 10 11 12 13 14 15    14 15 16 17 18 19 20
19 20 21 22 23 24 25    16 17 18 19 20 21 22    21 22 23 24 25 26 27
26 27 28 29 30 31       23 24 25 26 27 28 29    28 29 30 31
30

## Fortran

Already having a routine to produce a calendar simplified matters. However, it added to each row of days a row of annotations for those days (Xmas, etc. and also +2hh and -2hh for the days with two half-hour changes in length due to daylight saving: NZ also had daylight saving with changes of one half-hour) which meant that the field allowance was always four. With the annotations abandoned, this could be reduced to three, and, the first day column on a line does not need a leading space. Since the method employed variables for the layout, it could easily be twiddled to have three months per line (thus fitting into a line length of 80) or six (using most of a line length of 132) and so it became a matter of pulling together the needed routines from various places.

        MODULE DATEGNASH	!Assorted vexations. Time and calendar games, with local flavourings added.        TYPE DateBag		!Pack three parts into one.        INTEGER DAY,MONTH,YEAR	!The usual suspects.       END TYPE DateBag		!Simple enough.        CHARACTER*9 MONTHNAME(12),DAYNAME(0:6)	!Re-interpretations.       PARAMETER (MONTHNAME = (/"January","February","March","April",     1  "May","June","July","August","September","October","November",     2  "December"/))       PARAMETER (DAYNAME = (/"Sunday","Monday","Tuesday","Wednesday",     1  "Thursday","Friday","Saturday"/))	!Index this array with DayNum mod 7.       CHARACTER*3 MTHNAME(12)		!The standard abbreviations.       PARAMETER (MTHNAME = (/"JAN","FEB","MAR","APR","MAY","JUN",     1  "JUL","AUG","SEP","OCT","NOV","DEC"/))        INTEGER*4 JDAYSHIFT		!INTEGER*2 just isn't enough.       PARAMETER (JDAYSHIFT = 2415020)	!Thus shall 31/12/1899 give 0, a Sunday, via DAYNUM.       CONTAINS       INTEGER FUNCTION LSTNB(TEXT)  !Sigh. Last Not Blank.Concocted yet again by R.N.McLean (whom God preserve) December MM.Code checking reveals that the Compaq compiler generates a copy of the string and then finds the length of that when using the latter-day intrinsic LEN_TRIM. Madness!Can't   DO WHILE (L.GT.0 .AND. TEXT(L:L).LE.' ')	!Control chars. regarded as spaces.Curse the morons who think it good that the compiler MIGHT evaluate logical expressions fully.Crude GO TO rather than a DO-loop, because compilers use a loop counter as well as updating the index variable.Comparison runs of GNASH showed a saving of ~3% in its mass-data reading through the avoidance of DO in LSTNB alone.Crappy code for character comparison of varying lengths is avoided by using ICHAR which is for single characters only.Checking the indexing of CHARACTER variables for bounds evoked astounding stupidities, such as calculating the length of TEXT(L:L) by subtracting L from L!Comparison runs of GNASH showed a saving of ~25-30% in its mass data scanning for this, involving all its two-dozen or so single-character comparisons, not just in LSTNB.        CHARACTER*(*),INTENT(IN):: TEXT	!The bumf. If there must be copy-in, at least there need not be copy back.        INTEGER L		!The length of the bumf.         L = LEN(TEXT)		!So, what is it?    1    IF (L.LE.0) GO TO 2	!Are we there yet?         IF (ICHAR(TEXT(L:L)).GT.ICHAR(" ")) GO TO 2	!Control chars are regarded as spaces also.         L = L - 1		!Step back one.         GO TO 1		!And try again.    2    LSTNB = L		!The last non-blank, possibly zero.        RETURN			!Unsafe to use LSTNB as a variable.       END FUNCTION LSTNB	!Compilers can bungle it.      CHARACTER*2 FUNCTION I2FMT(N)	!These are all the same.       INTEGER*4 N			!But, the compiler doesn't offer generalisations.        IF (N.LT.0) THEN	!Negative numbers cop a sign.          IF (N.LT.-9) THEN	!But there's not much room left.            I2FMT = "-!"	!So this means 'overflow'.           ELSE			!Otherwise, room for one negative digit.            I2FMT = "-"//CHAR(ICHAR("0") - N)	!Thus. Presume adjacent character codes, etc.          END IF		!So much for negative numbers.        ELSE IF (N.LT.10) THEN	!Single digit positive?          I2FMT = " " //CHAR(ICHAR("0") + N)	!Yes. This.        ELSE IF (N.LT.100) THEN	!Two digit positive?          I2FMT = CHAR(N/10      + ICHAR("0"))	!Yes.     1           //CHAR(MOD(N,10) + ICHAR("0")) !These.        ELSE			!Otherwise,          I2FMT = "+!" 	!Positive overflow.        END IF			!So much for that.      END FUNCTION I2FMT	!No WRITE and FORMAT unlimbering.      CHARACTER*8 FUNCTION I8FMT(N)	!Oh for proper strings.       INTEGER*4 N       CHARACTER*8 HIC        WRITE (HIC,1) N    1   FORMAT (I8)        I8FMT = HIC      END FUNCTION I8FMT       SUBROUTINE SAY(OUT,TEXT)	!Gutted version that maintains no file logging output, etc.       INTEGER OUT       CHARACTER*(*) TEXT        WRITE (6,1) TEXT(1:LSTNB(TEXT))    1   FORMAT (A)      END SUBROUTINE SAY        INTEGER*4 FUNCTION DAYNUM(YY,M,D)	!Computes (JDayN - JDayShift), not JDayN.C   Conversion from a Gregorian calendar date to a Julian day number, JDayN.C   Valid for any Gregorian calendar date producing a Julian day numberC greater than zero, though remember that the Gregorian calendarC was not used before y1582m10d15 and often, not after that either.C thus in England (et al) when Wednesday 2'nd September 1752 (Julian style)C was followed by Thursday the 14'th, occasioning the Eleven Day riotsC because creditors demanded a full month's payment instead of 19/30'ths.C   The zero of the Julian day number corresponds to the first of JanuaryC 4713BC on the *Julian* calendar's naming scheme, as extended backwardsC with current usage into epochs when it did not exist: the proleptic Julian calendar.c This function employs the naming scheme of the *Gregorian* calendar,c and if extended backwards into epochs when it did not exist (thus thec proleptic Gregorian calendar) it would compute a zero for y-4713m11d24 *if*c it is supposed there was a year zero between 1BC and 1AD (as is convenientc for modern mathematics and astronomers and their simple calculations), *but*c 1BC immediately preceeds 1AD without any year zero in between (and is a leap year)c thus the adjustment below so that the date is y-4714m11d24 or 4714BCm11d24,c not that this name was in use at the time...c   Although the Julian calendar (introduced by himself in what we would call 45BC,c which was what the Romans occasionally called 709AUC) was provoked by thec "years of confusion" resulting from arbitrary application of the rulesc for the existing Roman calendar, other confusions remain unresolved,c so precise dating remains uncertain despite apparently precise specificationsc (and much later, Dennis the Short chose wrongly for the birth of Christ)c and the Roman practice of inclusive reckoning meant that every four yearsc was interpreted as every third (by our exclusive reckoning) so that thec leap years were not as we now interpret them. This was resolved by Augustusc but exactly when (and what date name is assigned) and whose writings usedc which system at the time of writing is a matter of more confusion,c and this has continued for centuries.C   Accordingly, although an algorithm may give a regular sequence of date names,c that does not mean that those date names were used at the time even if thec calendar existed then, because the interpretation of the algorithm varied.c This in turn means that a date given as being on the Julian calendarc prior to about 10AD is not as definite as it may appear and its alignmentc with the astronomical day number is uncertain even though the calculationc is quite definite.cC   Computationally, year 1 is preceded by year 0, in a smooth progression.C But there was never a year zero despite what astronomers like to say,C so the formula's year 0 corresponds to 1BC, year -1 to 2BC, and so on back.C Thus y-4713 in this counting would be 4714BC on the Gregorian calendar,C were it to have existed then which it didn't.C   To conform to the civil usage, the incoming YY, presumed a proper BC (negative)C and AD (positive) year is converted into the computational counting sequence, Y,C and used in the formula. If a YY = 0 is (improperly) offered, it will manifestC as 1AD. Thus YY = -4714 will lead to calculations with Y = -4713.C Thus, 1BC is a leap year on the proleptic Gregorian calendar.C   For their convenience, astronomers decreed that a day starts at noon, so thatC in Europe, observations through the night all have the same day number.C The current Western civil calendar however has the day starting just after midnightC and that day's number lasts until the following midnight.CC   There is no constraint on the values of D, which is just added as it stands.C This means that if D = 0, the daynumber will be that of the last day of theC previous month. Likewise, M = 0 or M = 13 will wrap around so that Y,M + 1,0C will give the last day of month M (whatever its length) as one day beforeC the first day of the next month.CC   Example: Y = 1970, M = 1, D = 1;  JDAYN = 2440588, a Thursday but MOD(2440588,7) = 3.C   and with the adjustment JDAYSHIFT, DAYNUM = 25568; mod 7 = 4 and DAYNAME(4) = "Thursday".C   The Julian Day number 2440588.0 is for NOON that Thursday, 2440588.5 is twelve hours later.C   And Julian Day number 2440587.625 is for three a.m. Thursday.CC   DAYNUM and MUNYAD are the infamous routines of H. F. Fliegel and T.C. van Flandern,C   presented in Communications of the ACM, Vol. 11, No. 10 (October, 1968).Carefully typed in again by R.N.McLean (whom God preserve) December XXMMIIX.C   Though I remain puzzled as to why they used I,J,K for Y,M,D,C given that the variables were named in the INTEGER statement anyway.        INTEGER*4 JDAYN		!Without rebasing, this won't fit in INTEGER*2.        INTEGER YY,Y,M,MM,D	!NB! Full year number, so 1970, not 70.Caution: integer division in Fortran does not produce fractional results.C The fractional part is discarded so that 4/3 gives 1 and -4/3 gives -1.C Thus 4/3 might be Trunc(4/3) or 4 div 3 in other languages. Beware of negative numbers!         Y = YY		!I can fiddle this copy without damaging the original's value.         IF (Y.LT.1) Y = Y + 1	!Thus YY = -2=2BC, -1=1BC, +1=1AD, ... becomes Y = -1, 0, 1, ...         MM = (M - 14)/12	!Calculate once. Note that this is integer division, truncating.         JDAYN = D - 32075	!This is the proper astronomer's Julian Day Number.     a    + 1461*(Y + 4800  + MM)/4     b    +  367*(M - 2     - MM*12)/12     c    -    3*((Y + 4900 + MM)/100)/4         DAYNUM = JDAYN - JDAYSHIFT	!Thus, *NOT* the actual *Julian* Day Number.       END FUNCTION DAYNUM		!But one such that Mod(n,7) gives day names. Could compute the day of the year somewhat as follows...c  DN:=D + (61*Month + (Month div 8)) div 2 - 30c        + if Month > 2 then FebLength - 30 else 0;        TYPE(DATEBAG) FUNCTION MUNYAD(DAYNUM)	!Oh for palindromic programming!Conversion from a Julian day number to a Gregorian calendar date. See JDAYN/DAYNUM.        INTEGER*4 DAYNUM,JDAYN	!Without rebasing, this won't fit in INTEGER*2.        INTEGER Y,M,D,L,N		!Y will be a full year number: 1950 not 50.         JDAYN = DAYNUM + JDAYSHIFT	!Revert to a proper Julian day number.         L = JDAYN + 68569	!Further machinations of H. F. Fliegel and T.C. van Flandern.         N = 4*L/146097         L = L - (146097*N + 3)/4         Y = 4000*(L + 1)/1461001         L = L - 1461*Y/4 + 31         M = 80*L/2447         D = L - 2447*M/80         L = M/11         M = M + 2 - 12*L         Y = 100*(N - 49) + Y + L         IF (Y.LT.1) Y = Y - 1	!The other side of conformity to BC/AD, as in DAYNUM.         MUNYAD%YEAR  = Y	!Now place for the world to see.         MUNYAD%MONTH = M         MUNYAD%DAY   = D       END FUNCTION MUNYAD	!A year has 365.2421988 days...        INTEGER FUNCTION PMOD(N,M)	!Remainder, mod M; always positive even if N is negative.c   For date calculations, the MOD function is expected to yield positive remainders,c in line with the idea that MOD(a,b) = MOD(a ± b,b) as is involved in shifting the zeroc of the daynumber count by a multiple of seven when considering the day of the week.c For this reason, the zero day was chosen to be 31/12/1899, a Sunday, so that allc day numbers would be positive. But, there was generation at Reefton in 1886.c   For some computers, the positive interpretation is implemented, for others, not.c In the case MOD(N,M) = N - Truncate(N/M)*M, MOD(-6,7) = -6 even though MOD(1,7) = 1.        INTEGER N,M			!The numbers. M presumed positive.         PMOD = MOD(MOD(N,M) + M,M)	!Double do does de deed.       END FUNCTION PMOD		!Simple enough.       SUBROUTINE CALENDAR(Y1,Y2,COLUMNS)	!Print a calendar, with holiday annotations.Careful with the MOD function. MOD(-6,7) may be negative on some systems, positive on others. Thus, PMOD.       INTEGER Y1,Y2,YEAR		!Ah yes. Year stuff.       INTEGER M,M1,M2,MONTH		!And within each year are the months.       INTEGER*4 DN1,DN2,DN,D		!But days are handled via day numbers.       INTEGER W,G			!Layout: width and gap.       INTEGER L,LINE			!Vertical layout.       INTEGER COL,COLUMNS,COLWIDTH	!Horizontal layout.       INTEGER CODE			!Days are not all alike.       CHARACTER*200 STRIPE(6),SPECIAL(6),MLINE,DLINE	!Scratchpads.        IF (Y1.LE.0) CALL SAY(MSG,"Despite the insinuations of "     1   //"astronomers seduced by the ease of their arithmetic, "     2   //"there is no year zero. 1AD is preceded by 1BC, "     3   //"corresponding to year -1, 2BC to year -2, etc.")        IF (Y1.LT.1582) CALL SAY(MSG,"This Gregorian calendar"     1   //" scheme did not exist prior to 1582.")c        COLUMNS = 4	!Number of months across the page.c        W = 4		!Width of a day's field.c        G = 3		!Added gap between month columns.        W = 3		!Abandon the annotation of the day's class, so just a space and two digits.        G = 1		!Set the gap to one.        COLWIDTH = 7*W + G	!Seven days to a week, plus a gap.      Y:DO YEAR = Y1,Y2		!Step through the years.          CALL SAY(MSG,"")	!Space out between each year's schedule.          IF (YEAR.EQ.0) THEN	!This year number is improper.            CALL SAY(MSG,"There is no year zero.")	!Declare correctness.            CYCLE Y		!Skip this year.          END IF		!Otherwise, no evasions.          MLINE = ""		!Prepare a field..          L = (COLUMNS*COLWIDTH - G - 8)/2	!Find the centre.          IF (YEAR.GT.0) THEN	!Ordinary Anno Domine years?            MLINE(L:) = I8FMT(YEAR)	!Yes. Place the year number.           ELSE			!Otherwise, we're in BC.            MLINE(L - 1:) = I8FMT(-YEAR)//"BC"	!There is no year zero.          END IF		!So much for year games.          CALL SAY(MSG,MLINE)		!Splot the year.          DO MONTH = 1,12,COLUMNS	!Step through the months of this YEAR.            M1 = MONTH			!The first of this lot.            M2 = MIN(12,M1 + COLUMNS - 1)	!The last.            MLINE = ""			!Scrub the month names.            DLINE = ""			!Wipe the day names in case COLUMNS does not divide 12.            STRIPE = ""			!Scrub the day table.            SPECIAL = ""		!And the associated special day remarks.c            L0 = W - 1			!Locate the first day number's first column.            L0 = 1			!Cram: no space in front of the Sunday day-of-the-month.            DO M = M1,M2		!Work through the months.              L = (COLWIDTH - G - LSTNB(MONTHNAME(M)))/2 - 1	!Centre the month name.              MLINE(L0 + L:) = MONTHNAME(M)	!Splot.              DO D = 0,6		!Prepare this month's day name heading.                L = L0 + (3 - W) + D*W	!Locate its first column.                DLINE(L:L + 2) = DAYNAME(D)(1:W - 1)	!Squish.              END DO		!On to the next day.              DN1 = DAYNUM(YEAR,M,1)	!Day number of the first day of the month.              DN2 = DAYNUM(YEAR,M + 1,0)!Thus the last, without annoyance.              COL = MOD(PMOD(DN1,7) + 7,7)	!What day of the week is the first day?              LINE = 1			!Whichever it is, it is on the first line.              D = 1			!Day of the month, not number of the day.              DO DN = DN1,DN2		!Step through the day numbers of this month.                L = L0 + COL*W		!Finger the starting column.                STRIPE(LINE)(L:L + 1) = I2FMT(D)	!Place the two-digit day number.                D = D + 1		!Advance to the next day of the current month                COL = COL + 1		!So, one more day along in the week.                IF (COL.GT.6) THEN	!A fresh week is needed?                  LINE = LINE + 1	!Yes.                  COL = 0		!Start the new week.                END IF		!So much for the end of a week.              END DO		!On to the next day of this month.              L0 = L0 + 7*W + G	!Locate the start column of the next month's column.            END DO	!On to the next month in this layer.            CALL SAY(MSG,MLINE)	!Name the months.C            CALL SAY(MSG,"")	!Set off.            CALL SAY(MSG,DLINE)	!Give the day name headings.            DO LINE = 1,6	!Now roll the day number table.              IF (STRIPE(LINE).NE."") THEN	!Perhaps there was no use of the sixth line.                CALL SAY(MSG,STRIPE(LINE))	!Ah well. Show the day numbers.              END IF				!So much for that week line.            END DO			!On to the next week line.          END DO		!On to the next batch of months of the YEAR.        END DO Y		!On to the next YEAR.        CALL SAY(MSG,"")	!Take a breath.      END SUBROUTINE CALENDAR	!Enough of this.      END MODULE DATEGNASH	!An ad-hoc assemblage.       PROGRAM SHOW1968		!Put it to the test.       USE DATEGNASH       INTEGER NCOL        DO NCOL = 1,6          CALL CALENDAR(1969,1969,NCOL)        END DO      END 

Selected output, lacking alas the outbursts from Snoopy: three months /line

                               1969
January              February                March
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1                     1
5  6  7  8  9 10 11   2  3  4  5  6  7  8   2  3  4  5  6  7  8
12 13 14 15 16 17 18   9 10 11 12 13 14 15   9 10 11 12 13 14 15
19 20 21 22 23 24 25  16 17 18 19 20 21 22  16 17 18 19 20 21 22
26 27 28 29 30 31     23 24 25 26 27 28     23 24 25 26 27 28 29
30 31
April                  May                  June
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5               1  2  3   1  2  3  4  5  6  7
6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14
13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21
20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28
27 28 29 30           25 26 27 28 29 30 31  29 30
July                 August               September
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2      1  2  3  4  5  6
6  7  8  9 10 11 12   3  4  5  6  7  8  9   7  8  9 10 11 12 13
13 14 15 16 17 18 19  10 11 12 13 14 15 16  14 15 16 17 18 19 20
20 21 22 23 24 25 26  17 18 19 20 21 22 23  21 22 23 24 25 26 27
27 28 29 30 31        24 25 26 27 28 29 30  28 29 30
31
October              November              December
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1      1  2  3  4  5  6
5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13
12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20
19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27
26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31
30


And with six...

                                                                1969
January              February                March                 April                  May                  June
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1                     1         1  2  3  4  5               1  2  3   1  2  3  4  5  6  7
5  6  7  8  9 10 11   2  3  4  5  6  7  8   2  3  4  5  6  7  8   6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14
12 13 14 15 16 17 18   9 10 11 12 13 14 15   9 10 11 12 13 14 15  13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21
19 20 21 22 23 24 25  16 17 18 19 20 21 22  16 17 18 19 20 21 22  20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28
26 27 28 29 30 31     23 24 25 26 27 28     23 24 25 26 27 28 29  27 28 29 30           25 26 27 28 29 30 31  29 30
30 31
July                 August               September              October              November              December
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2      1  2  3  4  5  6            1  2  3  4                     1      1  2  3  4  5  6
6  7  8  9 10 11 12   3  4  5  6  7  8  9   7  8  9 10 11 12 13   5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13
13 14 15 16 17 18 19  10 11 12 13 14 15 16  14 15 16 17 18 19 20  12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20
20 21 22 23 24 25 26  17 18 19 20 21 22 23  21 22 23 24 25 26 27  19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27
27 28 29 30 31        24 25 26 27 28 29 30  28 29 30              26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31
31                                                                30


## FreeBASIC

' version 17-02-2016' compile with: fbc -s console ' TRUE/FALSE are built-in constants since FreeBASIC 1.04' For older versions they have to be defined.#Ifndef TRUE            #Define FALSE 0    #Define TRUE Not FALSE#EndIf Function WD(m As Integer, d As Integer, y As Integer) As Integer    ' Zellerish    ' 0 = Sunday, 1 = Monday, 2 = Tuesday, 3 = Wednesday    ' 4 = Thursday, 5 = Friday, 6 = Saturday     If m < 3 Then        ' if m = 1 or m = 2 then        m += 12        y -= 1    End If    Return (y + (y \ 4) - (y \ 100) + (y \ 400) + d + ((153 * m + 8) \ 5)) Mod 7End Function Function LEAPYEAR(y As Integer) As Integer    If (y Mod 4) <> 0 Then Return FALSE    If (y Mod 100) = 0 AndAlso (y Mod 400) <> 0 Then Return FALSE    Return TRUEEnd Function ' ------=< main >=------ Dim As String wdn = "Mo Tu We Th Fr Sa Su"  ' weekday namesDim As String mo(1 To 12) => {"January", "February", "March", "April", _                         "May", "June", "July", "August", "September", _                                    "October", "November", "December"}Dim As String tmp1, tmp2, d(1 To 12) Dim As UInteger ml(1 To 12) => {31,28,31,30,31,30,31,31,30,31,30,31}Dim As UInteger i, i1, j, k, y = 1969Dim As UInteger m_row = 6 Do    While InKey <> "" : Wend  ' clear keyboard buffer    Print : Print " For wich year do want a calendar"    Print " Year must be greater then 1752"    Input " Input year (enter = 1969)";tmp1    If tmp1 = "" Then Exit Do    i = Val(tmp1)    If i < 1752 Then        Print        Print " Can only make a calendar for a year after 1752"        Beep : Sleep 5000, 1 : Print    Else        y = i : Exit Do    End IfLoop ClsDo    While InKey <> "" : Wend  ' clear keyboard buffer    Print : Print " Make device choice"    Print " 132 characters Line printer, 6x2 months (Enter or 1)"    Print " 80x43 display,               3x4 months          (2)"    Do        tmp1 = InKey        If tmp1 = Chr(13) Or tmp1 = "1" Then Exit Do, Do        If tmp1 = "2" Then            m_row = 3            Exit Do, Do        End If    Loop Until tmp1 <> ""    Print : Print " Enter, 1 or 2 only"    Beep : Sleep 5000, 1 : PrintLoopCls Dim As UInteger char_line = m_row * 22 - 1If LEAPYEAR(y) = TRUE Then ml(2) = 29 tmp1 = ""For i = 1 To 31    tmp1 = tmp1 + Right(("  " + Str(i)), 3)Next For i = 1 To 12    tmp2 = ""    j = WD(i,1, y)    If j = 0 Then j = 7    j = j - 1    tmp2 = Space(j * 3) + Left(tmp1, ml(i) * 3) + Space(21)    d(i) = tmp2Next Printtmp1 = Str(y)Print Space((char_line + (char_line And 1) - Len(tmp1)) \ 2); tmp1Print tmp2 = " "    ' make the weekday names lineFor i = 1 To m_row    tmp2 = tmp2 + wdn    If i < m_row Then tmp2 = tmp2 + "  "Next For i = 1 To 12 Step m_row    tmp1 = ""    For j = i To i + m_row -2 ' make the month names line        tmp1 = tmp1 + Left(Space((22 - Len(mo(j))) \ 2) + mo(j) + Space(21), 22)    Next    tmp1 = tmp1 + Space((22 - Len(mo(i + m_row -1))) \ 2) + mo(i + m_row -1)    Print tmp1    Print tmp2    For j = 1 To 85 Step 21        For k = i To i + m_row -2            Print Mid(d(k), j ,21); " ";        Next        Print Mid(d(i + m_row -1), j ,21)    Next    PrintNext ' empty keyboard bufferWhile InKey <> "" : Wend'Print : Print "hit any key to end programSleepEnd
Output:
                                                                1969

January               February               March                 April                  May                   June
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5                  1  2                  1  2      1  2  3  4  5  6            1  2  3  4                     1
6  7  8  9 10 11 12   3  4  5  6  7  8  9   3  4  5  6  7  8  9   7  8  9 10 11 12 13   5  6  7  8  9 10 11   2  3  4  5  6  7  8
13 14 15 16 17 18 19  10 11 12 13 14 15 16  10 11 12 13 14 15 16  14 15 16 17 18 19 20  12 13 14 15 16 17 18   9 10 11 12 13 14 15
20 21 22 23 24 25 26  17 18 19 20 21 22 23  17 18 19 20 21 22 23  21 22 23 24 25 26 27  19 20 21 22 23 24 25  16 17 18 19 20 21 22
27 28 29 30 31        24 25 26 27 28        24 25 26 27 28 29 30  28 29 30              26 27 28 29 30 31     23 24 25 26 27 28 29

July                 August              September              October               November              December
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5  6               1  2  3   1  2  3  4  5  6  7         1  2  3  4  5                  1  2   1  2  3  4  5  6  7
7  8  9 10 11 12 13   4  5  6  7  8  9 10   8  9 10 11 12 13 14   6  7  8  9 10 11 12   3  4  5  6  7  8  9   8  9 10 11 12 13 14
14 15 16 17 18 19 20  11 12 13 14 15 16 17  15 16 17 18 19 20 21  13 14 15 16 17 18 19  10 11 12 13 14 15 16  15 16 17 18 19 20 21
21 22 23 24 25 26 27  18 19 20 21 22 23 24  22 23 24 25 26 27 28  20 21 22 23 24 25 26  17 18 19 20 21 22 23  22 23 24 25 26 27 28
28 29 30 31           25 26 27 28 29 30 31  29 30                 27 28 29 30 31        24 25 26 27 28 29 30  29 30 31            

## F#

let getCalendar year =    let day_of_week month year =        let t =  [|0; 3; 2; 5; 0; 3; 5; 1; 4; 6; 2; 4|]        let y = if month < 3 then year - 1 else year        let m = month        let d = 1        (y + y / 4 - y / 100 + y / 400 + t.[m - 1] + d) % 7        //0 = Sunday, 1 = Monday, ...     let last_day_of_month month year =        match month with        | 2 -> if (0 = year % 4 && (0 = year % 400 || 0 <> year % 100)) then 29 else 28        | 4 | 6 | 9 | 11 -> 30        | _ -> 31     let get_month_calendar year month =        let min (x: int, y: int) = if x < y then x else y        let ld = last_day_of_month month year        let dw = 7 - (day_of_week month year)        [|[|1..dw|];          [|dw + 1..dw + 7|];          [|dw + 8..dw + 14|];           [|dw + 15..dw + 21|];           [|dw + 22..min(ld, dw + 28)|];           [|min(ld + 1, dw + 29)..ld|]|]     let sb_fold (f:System.Text.StringBuilder -> 'a -> System.Text.StringBuilder) (sb:System.Text.StringBuilder) (xs:'a array)  =        for x in xs do (f sb  x) |> ignore        sb     let sb_append (text:string) (sb:System.Text.StringBuilder) = sb.Append(text)     let sb_appendln sb = sb |> sb_append "\n" |> ignore     let sb_fold_in_range a b f sb = [|a..b|] |> sb_fold f sb |> ignore     let mask_builder mask = Printf.StringFormat<string -> string>(mask)    let center n (s:string) =        let l = (n - s.Length) / 2 + s.Length        let f n s = sprintf (mask_builder ("%" + (n.ToString()) + "s")) s        (f l s) + (f (n - l) "")    let left n (s:string)  = sprintf (mask_builder ("%-" + (n.ToString()) + "s")) s    let right n (s:string) = sprintf (mask_builder ("%" + (n.ToString()) + "s")) s     let array2string xs =         let ys = xs |> Array.map (fun x -> sprintf "%2d " x)        let sb = ys |> sb_fold (fun sb y -> sb.Append(y)) (new System.Text.StringBuilder())        sb.ToString()     let xsss =         let m = get_month_calendar year        [|1..12|] |> Array.map (fun i -> m i)     let months = [|"January"; "February"; "March"; "April"; "May"; "June"; "July"; "August"; "September"; "October"; "November"; "December"|]     let sb = new System.Text.StringBuilder()        sb |> sb_append "\n" |> sb_append (center 74 (year.ToString())) |> sb_appendln        for i in 0..3..9 do      sb |> sb_appendln      sb |> sb_fold_in_range i (i + 2) (fun sb i -> sb |> sb_append (center 21 months.[i]) |> sb_append "      ")            sb |> sb_appendln      sb |> sb_fold_in_range i (i + 2) (fun sb i -> sb |> sb_append "Su Mo Tu We Th Fr Sa " |> sb_append "      ")            sb |> sb_appendln      sb |> sb_fold_in_range i (i + 2) (fun sb i -> sb |> sb_append (right 21 (array2string (xsss.[i].[0]))) |> sb_append "      ")       sb |> sb_appendln      for j = 1 to 5 do               sb |> sb_fold_in_range i (i + 2) (fun sb i -> sb |> sb_append (left 21 (array2string (xsss.[i].[j]))) |> sb_append "      ")                sb |> sb_appendln    sb.ToString() let printCalendar year = getCalendar year
Output:
> printCalendar 1969;;
val it : string =
"
1969

January                   February                     March
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4                          1                          1
5  6  7  8  9 10 11        2  3  4  5  6  7  8        2  3  4  5  6  7  8
12 13 14 15 16 17 18        9 10 11 12 13 14 15        9 10 11 12 13 14 15
19 20 21 22 23 24 25       16 17 18 19 20 21 22       16 17 18 19 20 21 22
26 27 28 29 30 31          23 24 25 26 27 28          23 24 25 26 27 28 29
30 31

April                       May                       June
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4  5                    1  2  3        1  2  3  4  5  6  7
6  7  8  9 10 11 12        4  5  6  7  8  9 10        8  9 10 11 12 13 14
13 14 15 16 17 18 19       11 12 13 14 15 16 17       15 16 17 18 19 20 21
20 21 22 23 24 25 26       18 19 20 21 22 23 24       22 23 24 25 26 27 28
27 28 29 30                25 26 27 28 29 30 31       29 30

July                      August                    September
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4  5                       1  2           1  2  3  4  5  6
6  7  8  9 10 11 12        3  4  5  6  7  8  9        7  8  9 10 11 12 13
13 14 15 16 17 18 19       10 11 12 13 14 15 16       14 15 16 17 18 19 20
20 21 22 23 24 25 26       17 18 19 20 21 22 23       21 22 23 24 25 26 27
27 28 29 30 31             24 25 26 27 28 29 30       28 29 30
31

October                   November                   December
Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa       Su Mo Tu We Th Fr Sa
1  2  3  4                          1           1  2  3  4  5  6
5  6  7  8  9 10 11        2  3  4  5  6  7  8        7  8  9 10 11 12 13
12 13 14 15 16 17 18        9 10 11 12 13 14 15       14 15 16 17 18 19 20
19 20 21 22 23 24 25       16 17 18 19 20 21 22       21 22 23 24 25 26 27
26 27 28 29 30 31          23 24 25 26 27 28 29       28 29 30 31
30
"

## FutureBasic

 include "ConsoleWindow" dim as Str255 a open "UNIX", 1,"cal 1969"  do    line input #1, a    print a  until eof(1)close 1 

Output:

                             1969

January               February               March
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1                     1
5  6  7  8  9 10 11   2  3  4  5  6  7  8   2  3  4  5  6  7  8
12 13 14 15 16 17 18   9 10 11 12 13 14 15   9 10 11 12 13 14 15
19 20 21 22 23 24 25  16 17 18 19 20 21 22  16 17 18 19 20 21 22
26 27 28 29 30 31     23 24 25 26 27 28     23 24 25 26 27 28 29
30 31
April                  May                   June
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5               1  2  3   1  2  3  4  5  6  7
6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14
13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21
20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28
27 28 29 30           25 26 27 28 29 30 31  29 30

July                 August              September
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2      1  2  3  4  5  6
6  7  8  9 10 11 12   3  4  5  6  7  8  9   7  8  9 10 11 12 13
13 14 15 16 17 18 19  10 11 12 13 14 15 16  14 15 16 17 18 19 20
20 21 22 23 24 25 26  17 18 19 20 21 22 23  21 22 23 24 25 26 27
27 28 29 30 31        24 25 26 27 28 29 30  28 29 30
31
October               November              December
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1      1  2  3  4  5  6
5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13
12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20
19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27
26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31
30


## Perl 6

Works with: Rakudo version 2015.12
my $months-per-col = 3;my @week-day-names = <Mo Tu We Th Fr Sa Su>;my @month-names = <Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec>; my Int$year = +(@*ARGS.shift || 1969); say fmt-year($year);exit; sub fmt-year ($year) {         my $str = (' ' x 30) ~$year ~ "\n";         my Array @month-strs;        @month-strs[$_] = fmt-month($year, $_).lines.Array for 1 .. 12; loop ( my$month = 1; $month <= 12;$month += $months-per-col ) { while @month-strs[$month] {                        for ^$months-per-col { next unless @month-strs[$month+$_];$str ~= @month-strs[$month+$_].shift;                                $str ~= " " x 3; }$str ~= "\n";                }                $str ~= "\n"; } return$str;}sub fmt-month ($year,$month) {        my $str = sprintf "%-20s\n", @month-names[$month-1];        $str ~= @week-day-names~"\n"; my$date = DateTime.new(year => $year, month =>$month);        my $week-day =$date.day-of-week;         $str ~= (" " xx$week-day-1).join(" ");         for $date.day ..$date.days-in-month -> $day {$date = DateTime.new(year => $year, month =>$month, day => $day);$str ~= " " if 1 < $week-day < 8; if$week-day == 8 {                        $str ~= "\n";$week-day = 1;                }                $str ~= sprintf "%2d",$day;                 $week-day++; }$str ~= " " if $week-day < 8;$str ~= ("  " xx 8-$week-day).join(" ");$str ~= "\n";        return str;}  ## Phix Gregorian calender only. include builtins\timedate.e function centre(string s, integer width)integer pad = width-length(s), left = floor(pad/2), right = pad-left return repeat(' ',left)&s&repeat(' ',right)end function function one_month(integer year, integer month)integer dow = day_of_week(year,month,1)sequence ldm = adjust_timedate(iff(month=12?{year+1,1,1,0,0,0,0,0} :{year,month+1,1,0,0,0,0,0}), timedelta(days:=-1))sequence res = {centre(format_timedate(ldm,"Mmmm"),20),"Su Mo Tu We Th Fr Sa"}integer lastday = ldm[DT_DAY]string line = repeat(' ',20)integer p = dow*3-2 for d=1 to lastday do line[p..p+1] = sprintf("%2d",d) p += 3 if dow=7 or d=lastday then res = append(res,line) line = repeat(' ',20) dow = 1 p = 1 else dow += 1 end if end for return resend function procedure print_calendar(integer year, integer width)sequence months = repeat(0,12)integer wide = floor((width+2)/22) printf(1,centre("[Spot Reserved For Snoopy]",width)&"\n") printf(1,centre(sprintf("%d",year),width)&"\n") for month=1 to 12 do months[month] = one_month(year,month) end for for month=1 to 12 by wide do for k=1 to 9 do -- (more than enough) integer any = 0 string line = "", this for j=0 to wide-1 do if length(line) then line &= " " end if if k>length(months[month+j]) then line &= repeat(' ',20) else line &= months[month+j][k] any = 1 end if end for if any=0 then exit end if printf(1,centre(line,width)&"\n") end for end forend procedure print_calendar(1969,80)printf(1,join(repeat("1234567890",8),"")&"\n")print_calendar(1969,132)printf(1,join(repeat("1234567890",13),"")&"12\n") Output:  [Spot Reserved For Snoopy] 1969 January February March Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 30 31 April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 27 28 29 30 25 26 27 28 29 30 31 29 30 July August September Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 31 October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 30 12345678901234567890123456789012345678901234567890123456789012345678901234567890 [Spot Reserved For Snoopy] 1969 January February March April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 27 28 29 30 25 26 27 28 29 30 31 29 30 30 31 July August September October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 1 2 3 4 1 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 31 30 123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012  ## PicoLisp This "calendar" is nicely formatted, and fits into 20 columns ;-) (de cal (Year) (prinl "====== " Year " ======") (for Dat (range (date Year 1 1) (date Year 12 31)) (let D (date Dat) (tab (3 3 4 8) (when (= 1 (caddr D)) (get *Mon (cadr D)) ) (caddr D) (day Dat *Day) (when (=0 (% (inc Dat) 7)) (pack "Week " (week Dat)) ) ) ) ) ) (cal 1969) Output: ====== 1969 ====== Jan 1 Wed 2 Thu 3 Fri 4 Sat 5 Sun 6 Mon Week 2 7 Tue .... 28 Sat 29 Sun 30 Mon Week 27 Jul 1 Tue 2 Wed 3 Thu 4 Fri .... 25 Thu 26 Fri 27 Sat 28 Sun 29 Mon Week 53 30 Tue 31 Wed ## Pike the Calendar in Pike does not handle the transitions from the Julian to the Gregorian calendar, but it handles those separately. the default calendar is ISO, other options are Gregorian, Julian, Bahai, Coptic, Islamic and Discordian. this script also highlights holidays by region. regions may be chosen by 2-letter country name, as well as some special 'regions': christianity, orthodox, bahai, islamic, among others. #!/bin/env pike int main(int argc, array(string) argv){ object cal = Calendar; object year; string region = "us"; array date = argv[1..]; if (sizeof(date) && objectp(Calendar[date[0]]) && Calendar[date[0]]->Day) { cal = Calendar[date[0]]; date = Array.shift(date)[1]; } if (sizeof(date) && (int)date[0]) { year = cal.Year((int)date[0]); date = Array.shift(date)[1]; } if (sizeof(date)) region = date[0]; if (!year) year = cal.Year(); print_year(year, region);} array make_month(object month, int field_width, void|string region){ array out =({}); mapping holidays = ([]); object today = Calendar.Day(); if (region) holidays = Calendar.Events.find_region(region)->scan_events(month); array weekday_names = sprintf("%*.*s", field_width, field_width, month->week()->days()->week_day_shortname()[*]); out += ({ ({ month->month_name(), month->month_no(), month->year_name() }) }); out += ({ weekday_names }); out += showday(month->weeks()->days()[*][*], month, today, holidays, field_width); out += ({ ({ " "*field_width })*sizeof(weekday_names) }); return out;} string print_month(object _month, void|int field_width, void|string region){ if (!field_width) field_width = 2; array month = make_month(_month, field_width, region); string out = ""; out += sprintf("%|*s\n", (field_width+1)*sizeof(month[1])-1, sprintf("%s", month[0][0])); out += sprintf((month[1..][*]*" ")*"\n"); return out;} string print_year(object year, void|string region){ array output = ({}); int day_width = 2; int columns = Stdio.stdout.tcgetattr()->columns; int month_width = sizeof(make_month(year->month(), day_width)[1]) * (day_width+1) - 1; if (columns < month_width) columns = month_width; // try to find an optimal good looking solution to spread the months // across the terminal width // for the common calendar of 12 months this is easy but we need to // account for caledars that have more than 12 months float max_width = (float)((columns+2)/(month_width+2)); float max_height = ceil(year->number_of_months()/max_width); float w = max_width; while(ceil(year->number_of_months()/(w-1)) == max_height) w--; foreach(print_month(year->months()[*], day_width, region)/w;; array row) { array rows = row[*]/"\n"; int l = max(@sizeof(rows[*])); foreach(rows; int i;) { // the last line of each month is an empty line. // repeat the line as many times as needed to make the months equally long rows[i]+=({ rows[i][-1] })*(l-sizeof(rows[i])); } rows = Array.transpose(rows); output += rows[*]*" "; } write("%*|s\n", sizeof(output[1]), year->format_nice()); write(output * "\n"); write("\n");} string showday(object day, object month, object today, mapping holidays, int field_width){ string dayname; if (day->month() == month) { dayname = (string)day->month_day(); dayname = " "*(sizeof((string)month->number_of_days())-sizeof(dayname))+dayname; if (day == today) dayname = sprintf("%|*.*s", field_width, field_width, dayname); else dayname = sprintf("%|*.*s", field_width, field_width, dayname); if (holidays[day]) dayname = sprintf("%|s", dayname); } else dayname = " "*field_width; return dayname;}  Output: (holidays lost in copy-paste)  1969 January February March Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 6 7 8 9 10 11 12 3 4 5 6 7 8 9 3 4 5 6 7 8 9 13 14 15 16 17 18 19 10 11 12 13 14 15 16 10 11 12 13 14 15 16 20 21 22 23 24 25 26 17 18 19 20 21 22 23 17 18 19 20 21 22 23 27 28 29 30 31 24 25 26 27 28 24 25 26 27 28 29 30 31 April May June Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 4 1 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 30 July August September Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 1 2 3 4 5 6 7 7 8 9 10 11 12 13 4 5 6 7 8 9 10 8 9 10 11 12 13 14 14 15 16 17 18 19 20 11 12 13 14 15 16 17 15 16 17 18 19 20 21 21 22 23 24 25 26 27 18 19 20 21 22 23 24 22 23 24 25 26 27 28 28 29 30 31 25 26 27 28 29 30 31 29 30 October November December Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 3 4 5 6 7 6 7 8 9 10 11 12 3 4 5 6 7 8 9 8 9 10 11 12 13 14 13 14 15 16 17 18 19 10 11 12 13 14 15 16 15 16 17 18 19 20 21 20 21 22 23 24 25 26 17 18 19 20 21 22 23 22 23 24 25 26 27 28 27 28 29 30 31 24 25 26 27 28 29 30 29 30 31  ## PL/I  calendar: procedure (year) options (main); declare year character (4) varying; declare (a, b, c) (0:5,0:6) character (3); declare name_month(12) static character (9) varying initial ( 'JANUARY', 'FEBRUARY', 'MARCH', 'APRIL', 'MAY', 'JUNE', 'JULY', 'AUGUST', 'SEPTEMBER', 'OCTOBER', 'NOVEMBER', 'DECEMBER'); declare i fixed; declare (mm, mmp1, mmp2) pic '99'; put edit (center('CALENDAR FOR ' || YEAR, 67)) (a); put skip (2); do mm = 1 to 12 by 3; mmp1 = mm + 1; mmp2 = mm + 2; call prepare_month('01' || mm || YEAR, a); call prepare_month('01' || mmp1 || YEAR, b); call prepare_month('01' || mmp2 || YEAR, c); put skip edit (center(name_month(mm), 23), center(name_month(mmp1), 23), center(name_month(mmp2), 23) ) (a); put skip edit ((3)' M T W T F S S ') (a); do i = 0 to 5; put skip edit (a(i,*), b(i,*), c(i,*)) (7 a, x(2)); end; end; prepare_month: procedure (start, month); declare month(0:5,0:6) character (3); declare start character (8); declare i pic 'ZZ9'; declare offset fixed; declare (j, day) fixed binary (31); declare (this_month, next_month, k) fixed binary; day = days(start, 'DDMMYYYY'); offset = weekday(day) - 1; if offset = 0 then offset = 7; month = ''; do j = day by 1; this_month = substr(daystodate(j, 'DDMMYYYY'), 3, 2); next_month = substr(daystodate(j+1, 'DDMMYYYY'), 3, 2); if this_month^= next_month then leave; end; i = 1; do k = offset-1 to offset+j-day-1; month(k/7, mod(k,7)) = i; i = i + 1; end;end prepare_month; end calendar;  Output:  CALENDAR FOR 1969 JANUARY FEBRUARY MARCH M T W T F S S M T W T F S S M T W T F S S 1 2 3 4 5 1 2 1 2 6 7 8 9 10 11 12 3 4 5 6 7 8 9 3 4 5 6 7 8 9 13 14 15 16 17 18 19 10 11 12 13 14 15 16 10 11 12 13 14 15 16 20 21 22 23 24 25 26 17 18 19 20 21 22 23 17 18 19 20 21 22 23 27 28 29 30 31 24 25 26 27 28 24 25 26 27 28 29 30 31 APRIL MAY JUNE M T W T F S S M T W T F S S M T W T F S S 1 2 3 4 5 6 1 2 3 4 1 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 30 JULY AUGUST SEPTEMBER M T W T F S S M T W T F S S M T W T F S S 1 2 3 4 5 6 1 2 3 1 2 3 4 5 6 7 7 8 9 10 11 12 13 4 5 6 7 8 9 10 8 9 10 11 12 13 14 14 15 16 17 18 19 20 11 12 13 14 15 16 17 15 16 17 18 19 20 21 21 22 23 24 25 26 27 18 19 20 21 22 23 24 22 23 24 25 26 27 28 28 29 30 31 25 26 27 28 29 30 31 29 30 OCTOBER NOVEMBER DECEMBER M T W T F S S M T W T F S S M T W T F S S 1 2 3 4 5 1 2 1 2 3 4 5 6 7 6 7 8 9 10 11 12 3 4 5 6 7 8 9 8 9 10 11 12 13 14 13 14 15 16 17 18 19 10 11 12 13 14 15 16 15 16 17 18 19 20 21 20 21 22 23 24 25 26 17 18 19 20 21 22 23 22 23 24 25 26 27 28 27 28 29 30 31 24 25 26 27 28 29 30 29 30 31  Extract for 2013:  CALENDAR FOR 2013 JANUARY FEBRUARY MARCH M T W T F S S M T W T F S S M T W T F S S 1 2 3 4 5 6 1 2 3 1 2 3 7 8 9 10 11 12 13 4 5 6 7 8 9 10 4 5 6 7 8 9 10 14 15 16 17 18 19 20 11 12 13 14 15 16 17 11 12 13 14 15 16 17 21 22 23 24 25 26 27 18 19 20 21 22 23 24 18 19 20 21 22 23 24 28 29 30 31 25 26 27 28 25 26 27 28 29 30 31  ## Python The Python calendar.prcal function prints calendars with the following formatting options: optional parameters w, l, and c are for date column width, lines per week, and number of spaces between month columns, respectively. >>> import calendar>>> help(calendar.prcal)Help on method pryear in module calendar: pryear(self, theyear, w=0, l=0, c=6, m=3) method of calendar.TextCalendar instance Print a years calendar. >>> calendar.prcal(1969) 1969 January February MarchMo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 6 7 8 9 10 11 12 3 4 5 6 7 8 9 3 4 5 6 7 8 913 14 15 16 17 18 19 10 11 12 13 14 15 16 10 11 12 13 14 15 1620 21 22 23 24 25 26 17 18 19 20 21 22 23 17 18 19 20 21 22 2327 28 29 30 31 24 25 26 27 28 24 25 26 27 28 29 30 31 April May JuneMo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 4 1 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 814 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 1521 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 2228 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 30 July August SeptemberMo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 1 2 3 4 5 6 7 7 8 9 10 11 12 13 4 5 6 7 8 9 10 8 9 10 11 12 13 1414 15 16 17 18 19 20 11 12 13 14 15 16 17 15 16 17 18 19 20 2121 22 23 24 25 26 27 18 19 20 21 22 23 24 22 23 24 25 26 27 2828 29 30 31 25 26 27 28 29 30 31 29 30 October November DecemberMo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 3 4 5 6 7 6 7 8 9 10 11 12 3 4 5 6 7 8 9 8 9 10 11 12 13 1413 14 15 16 17 18 19 10 11 12 13 14 15 16 15 16 17 18 19 20 2120 21 22 23 24 25 26 17 18 19 20 21 22 23 22 23 24 25 26 27 2827 28 29 30 31 24 25 26 27 28 29 30 29 30 31 ## Racket #lang racket(require racket/date net/base64 file/gunzip)(define (calendar yr) (define (nsplit n l) (if (null? l) l (cons (take l n) (nsplit n (drop l n))))) (define months (for/list ([mn (in-naturals 1)] [mname '(January February March April May June July August September October November December)]) (define s (find-seconds 0 0 12 1 mn yr)) (define pfx (date-week-day (seconds->date s))) (define days (let ([? (if (= mn 12) (λ(x y) y) (λ(x y) x))]) (round (/ (- (find-seconds 0 0 12 1 (? (+ 1 mn) 1) (? yr (+ 1 yr))) s) 60 60 24)))) (list* (~a mname #:width 20 #:align 'center) "Su Mo Tu We Th Fr Sa" (map string-join (nsplit 7 (,@(make-list pfx " ") ,@(for/list ([d days]) (~a (+ d 1) #:width 2 #:align 'right)) ,@(make-list (- 42 pfx days) " "))))))) (let ([s #"nZA7CsAgDED3nCLgoAU/3Uvv4SCE3qKD5OyNWvoBhdIHSswjMYp4YR2z80Tk8StOgP sY0EyrMZOE6WsL3u4G5lyV+d8MyVOy8hZBt7RSMca9Ac/KUIs1L/BOysb50XMtMzEj ZqiuRxIVqI+4kSpy7GqpXNsz+bfpfWIGOAA="] [o (open-output-string)]) (inflate (open-input-bytes (base64-decode s)) o) (display (regexp-replace #rx"~a" (get-output-string o) (~a yr)))) (for-each displayln (dropf-right (for*/list ([3ms (nsplit 3 months)] [s (apply map list 3ms)]) (regexp-replace #rx" +" (string-join s "   ") ""))                 (λ(s) (equal? "" s))))) (calendar 1969)
Output:
           ,-~~-.___.                                         ----
/ ()=(()   \                                        1969
(   (        0                                       ----
\._\, ,----'
##XXXxxxxxxx
/  ---'~;
/    /~|-
=(   ~~  |
/~~~~~~~~~~~~~~~~~~~~~\
/_______________________\
/_________________________\
/___________________________\
|____________________|
|____________________|
|____________________|
|                    |

January                February                March
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4                      1                      1
5  6  7  8  9 10 11    2  3  4  5  6  7  8    2  3  4  5  6  7  8
12 13 14 15 16 17 18    9 10 11 12 13 14 15    9 10 11 12 13 14 15
19 20 21 22 23 24 25   16 17 18 19 20 21 22   16 17 18 19 20 21 22
26 27 28 29 30 31      23 24 25 26 27 28      23 24 25 26 27 28 29
30 31
April                   May                    June
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5                1  2  3    1  2  3  4  5  6  7
6  7  8  9 10 11 12    4  5  6  7  8  9 10    8  9 10 11 12 13 14
13 14 15 16 17 18 19   11 12 13 14 15 16 17   15 16 17 18 19 20 21
20 21 22 23 24 25 26   18 19 20 21 22 23 24   22 23 24 25 26 27 28
27 28 29 30            25 26 27 28 29 30 31   29 30

July                  August               September
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5                   1  2       1  2  3  4  5  6
6  7  8  9 10 11 12    3  4  5  6  7  8  9    7  8  9 10 11 12 13
13 14 15 16 17 18 19   10 11 12 13 14 15 16   14 15 16 17 18 19 20
20 21 22 23 24 25 26   17 18 19 20 21 22 23   21 22 23 24 25 26 27
27 28 29 30 31         24 25 26 27 28 29 30   28 29 30
31
October                November               December
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4                      1       1  2  3  4  5  6
5  6  7  8  9 10 11    2  3  4  5  6  7  8    7  8  9 10 11 12 13
12 13 14 15 16 17 18    9 10 11 12 13 14 15   14 15 16 17 18 19 20
19 20 21 22 23 24 25   16 17 18 19 20 21 22   21 22 23 24 25 26 27
26 27 28 29 30 31      23 24 25 26 27 28 29   28 29 30 31
30

## REXX

Rather than build a program from scratch, I took my generalized REXX program that generated (as an
option) any calendar for any month, and by extension, any number of months (so that an entire
year could be displayed/written).   To make the program much smaller, a LOT of code was removed
(but it's still a sledgehammer doing the work of a small hammer).

Some of the code removed:

• almost all error checking and the issuing of error messages.
• the option of using "simple" characters as opposed to a true grid (of ASCII extended characters).
• the option of highlighting of today's date.
• the option of using colors.
• the specifying of what lang:uage to use (over 90 languages, default is English).
• the option of using indentation.
• the option of using different date formats (to specify the date).
• the option of using a time addition/subtraction for the date (* -4score-7years).
• the option of showing the phases of the moon.
• the option of showing the day-of-the-year (as on financial calendars and others).
• the option of specifying a calendar fill character (those empty cells in a monthly calender).
• the option of drawing Snoopy (three versions) and also many other animals/ASCII art.
• the specifing of alternate outputs (a file/printer/XEDIT/stack/GLOBALVs/etc).
• the option of displaying the year in blocked form (at the top of the calendar):
                   11          9999999       6666666       9999999
111         999999999     666666666     999999999
1111        99      99    66      66    99      99
11        99      99    66            99      99
11        99     999    66            99     999
11         999999999    66 666666      999999999
11          99999 99    6666666666      99999 99
11                99    666     66            99
11                99    66      66            99
11        99      99    66      66    99      99
111111       99999999      66666666      99999999
111111        999999        666666        999999


Most of the code is dealing with drawing a cell (grid) for each day-of-the-month, so the program
is a bit more complex than it has to be for this task.   Also, it was designed for any year, any
month(s), and any size screen/device to show (display) it.   Accommodations were made in the program
to allow the choice of what type of cells would be generated: small/smaller/smallest for height, and
narrow/narrower/narrowest for the width.   The size (width/depth) of the output device/terminal can be
specified.   The choice could've been performed programmatically, but I never believe that a program
could best choose over what the user wants, as it depends on esthetics and looks (fashion).

/*REXX program to show any year's (monthly) calendar (with/without grid)*/ @abc='abcdefghijklmnopqrstuvwxyz'; @abcU=@abc; upper @abcUcalfill=' '; mc=12; _='1 3 1234567890' "fb"xparse var _ grid calspaces # chk . cv_ days.1 days.2 days.3 daysn sd sw_=0; parse var _ cols 1 jd 1 lowerCase 1 maxKalPuts 1 narrow 1,                 narrower 1 narrowest 1 short 1 shorter 1 shortest 1,                 small 1 smaller 1 smallest 1 upperCaseparse arg mm '/' dd "/" yyyy _ '(' ops;  uops=opsif _\=='' | \is#(mm) | \is#(dd) | \is#(yyyy) then call erx 86   do while ops\==''; ops=strip(ops,'L'); parse var ops _1 2 1 _ . 1 _o ops  upper _       select       when  abb('CALSPaces')  then calspaces=nai()       when  abb('DEPth')      then        sd=nai()       when abbn('GRIDs')      then      grid=no()       when abbn('LOWercase')  then lowerCase=no()       when  abb('CALMONths')  then        mc=nai()       when abbn('NARrow')     then    narrow=no()       when abbn('NARROWER')   then  narrower=no()       when abbn('NARROWESt')  then narrowest=no()       when abbn('SHORt')      then     short=no()       when abbn('SHORTER')    then   shorter=no()       when abbn('SHORTESt')   then  shortest=no()       when abbn('SMALl')      then     small=no()       when abbn('SMALLER')    then   smaller=no()       when abbn('SMALLESt')   then  smallest=no()       when abbn('UPPercase')  then upperCase=no()       when  abb('WIDth')      then        sw=nai()       otherwise nop       end    /*select*/  end         /*do while opts\== ...*/ mc=int(mc,'monthscalender'); if mc>0 then cal=1days='Sunday Monday Tuesday Wednesday Thursday Friday Saturday'months='January February March April May June July August September October November December'days=' 'days;  months=' 'monthscyyyy=right(date(),4);  hyy=left(cyyyy,2);  lyy=right(cyyyy,2)dy.=31; _=30; parse var _ dy.4 1 dy.6 1 dy.9 1 dy.11; dy.2=28+ly(yyyy)yy=right(yyyy,2); sd=p(sd 43); sw=p(sw 80); cw=10; cindent=1; calwidth=76if small    then do; narrow=1   ; short=1   ; endif smaller  then do; narrower=1 ; shorter=1 ; endif smallest then do; narrowest=1; shortest=1; endif shortest then shorter=1if shorter  then short  =1if narrow    then do; cw=9; cindent=3; calwidth=69; endif narrower  then do; cw=4; cindent=1; calwidth=34; endif narrowest then do; cw=2; cindent=1; calwidth=20; endcv_=calwidth+calspaces+2calfill=left(copies(calfill,cw),cw)      do j=1 for 7;         _=word(days,j)            do jw=1 for 3;  _d=strip(substr(_,cw*jw-cw+1,cw))            if jw=1 then _d=centre(_d,cw+1)                    else _d=left(_d,cw+1)            days.jw=days.jw||_d            end   /*jw*/      __=daysn      if narrower  then daysn=__||centre(left(_,3),5)      if narrowest then daysn=__||center(left(_,2),3)      end   /*j*/_yyyy=yyyy; calPuts=0; cv=1; _mm=mm+0; month=word(months,mm)dy.2=28+ly(_yyyy); dim=dy._mm; _dd=01; dow=dow(_mm,_dd,_yyyy); $dd=dd+0 /*─────────────────────────────now: the business of the building the cal*/call calGen do _j=2 to mc if cv_\=='' then do cv=cv+cv_ if cv+cv_>=sw then do; cv=1; call calPut call fcalPuts;call calPb end else calPuts=0 end else do;call calPb;call calPut;call fcalPuts;end _mm=_mm+1; if _mm==13 then do; _mm=1; _yyyy=_yyyy+1; end month=word(months,_mm); dy.2=28+ly(_yyyy); dim=dy._mm dow=dow(_mm,_dd,_yyyy);$dd=0; call calGen               end   /*_j*/call fcalPutsreturn _ /*─────────────────────────────calGen subroutine────────────────────────*/calGen: cellX=;cellJ=;cellM=;calCells=0;calline=0call calPutcall calPutl copies('─',calwidth),"┌┐"; call calHdcall calPutl month ' ' _yyyy          ; call calHdif narrowest | narrower then call calPutl daysn                        else do jw=1 for 3                             if space(days.jw)\=='' then call calPutl days.jw                             endcalft=1; calfb=0  do jf=1 for dow-1; call cellDraw calFill,calFill; end  do jy=1 for dim; call cellDraw jy; endcalfb=1  do 7; call cellDraw calFill,calFill; endif sd>32 & \shorter then call calPutreturn /*─────────────────────────────cellDraw subroutine──────────────────────*/cellDraw: parse arg zz,cdDOY;zz=right(zz,2);calCells=calCells+1if calCells>7 then do                   calLine=calLine+1                   cellX=substr(cellX,2)                   cellJ=substr(cellJ,2)                   cellM=substr(cellM,2)                   cellB=translate(cellX,,")(─-"#)                   if calLine==1 then call cx                   call calCsm; call calPutl cellX; call calCsj; call cx                   cellX=; cellJ=; cellM=; calCells=1                   endcdDOY=right(cdDOY,cw); cellM=cellM'│'center('',cw)cellX=cellX'│'centre(zz,cw); cellJ=cellJ'│'center('',cw)return /*═════════════════════════════general 1-line subs══════════════════════*/abb:arg abbu;parse arg abb;return abbrev(abbu,_,abbl(abb))abbl:return verify(arg(1)'a',@abc,'M')-1abbn:parse arg abbn;return abb(abbn)|abb('NO'abbn)calCsj:if sd>49&\shorter then call calPutl cellB;if sd>24&\short then call calPutl cellJ; returncalCsm:if sd>24&\short then call calPutl cellM;if sd>49&\shorter then call calPutl cellB;returncalHd:if sd>24&\shorter then call calPutl;if sd>32&\shortest then call calPutl;returncalPb:if \grid&shortest then call put chk;returncalPut:calPuts=calPuts+1;maxKalPuts=max(maxKalPuts,calPuts);if symbol('CT.'calPuts)\=='VAR' then ct.calPuts=;ct.calPuts=overlay(arg(1),ct.calPuts,cv);returncalPutl:call calPut copies(' ',cindent)left(arg(2)"│",1)center(arg(1),calwidth)||right('│'arg(2),1);returncx:cx_='├┤';cx=copies(copies('─',cw)'┼',7);if calft then do;cx=translate(cx,'┬',"┼");calft=0;end;if calfb then do;cx=translate(cx,'┴',"┼");cx_='└┘';calfb=0;end;call calPutl cx,cx_;returndow:procedure;arg m,d,y;if m<3 then do;m=m+12;y=y-1;end;yl=left(y,2);yr=right(y,2);w=(d+(m+1)*26%10+yr+yr%4+yl%4+5*yl)//7;if w==0 then w=7;return wer:parse arg _1,_2;call '$ERR' "14"p(_1) p(word(_1,2) !fid(1)) _2;if _1<0 then return _1;exit resulterr:call er '-'arg(1),arg(2);return ''erx:call er '-'arg(1),arg(2);exit ''fcalPuts: do j=1 for maxKalPuts;call put ct.j;end;ct.=;maxKalPuts=0;calPuts=0;returnint:int=numx(arg(1),arg(2));if \isint(int) then call erx 92,arg(1) arg(2);return int/1is#:return verify(arg(1),#)==0isint:return datatype(arg(1),'W')lower:return translate(arg(1),@abc,@abcU)ly:arg _;if length(_)==2 then _=hyy||_;ly=_//4==0;if ly==0 then return 0;ly=((_//100\==0)|_//400==0);return lyna:if arg(1)\=='' then call erx 01,arg(2);parse var ops na ops;if na=='' then call erx 35,_o;return nanai:return int(na(),_o)nan:return numx(na(),_o)no:if arg(1)\=='' then call erx 01,arg(2);return left(_,2)\=='NO'num:procedure;parse arg x .,f,q;if x=='' then return x;if datatype(x,'N') then return x/1;x=space(translate(x,,','),0);if datatype(x,'N') then return x/1;return numnot()numnot:if q==1 then return x;if q=='' then call er 53,x f;call erx 53,x fnumx:return num(arg(1),arg(2),1)p:return word(arg(1),1)put:_=arg(1);_=translate(_,,'_'chk);if \grid then _=ungrid(_);if lowerCase then _=lower(_);if upperCase then upper _;if shortest&_=' ' then return;call tell _;returntell:say arg(1);returnungrid:return translate(arg(1),,"│║─═┤┐└┴┬├┼┘┌╔╗╚╝╟╢╞╡╫╪╤╧╥╨╠╣") output when using the input of: 1/1/1969 (noGrid smallest narrowest)  «Snoopy "picture" here» January 1969 February 1969 March 1969 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 30 31 April 1969 May 1969 June 1969 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 27 28 29 30 25 26 27 28 29 30 31 29 30 July 1969 August 1969 September 1969 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 31 October 1969 November 1969 December 1969 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 30  Output when using the input of: 1/1/1969 (smallest narrowest width 156 calSpaces 5) A width of 156 was used to illustrate showing a grid, otherwise it would fit in 132 columns.  ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ │ January 1969 │ │ February 1969 │ │ March 1969 │ │ April 1969 │ │ May 1969 │ │ June 1969 │ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ │ │ │ │ 1│ 2│ 3│ 4│ │ │ │ │ │ │ │ 1│ │ │ │ │ │ │ │ 1│ │ │ │ 1│ 2│ 3│ 4│ 5│ │ │ │ │ │ 1│ 2│ 3│ │ 1│ 2│ 3│ 4│ 5│ 6│ 7│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │ 5│ 6│ 7│ 8│ 9│10│11│ │ 2│ 3│ 4│ 5│ 6│ 7│ 8│ │ 2│ 3│ 4│ 5│ 6│ 7│ 8│ │ 6│ 7│ 8│ 9│10│11│12│ │ 4│ 5│ 6│ 7│ 8│ 9│10│ │ 8│ 9│10│11│12│13│14│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │12│13│14│15│16│17│18│ │ 9│10│11│12│13│14│15│ │ 9│10│11│12│13│14│15│ │13│14│15│16│17│18│19│ │11│12│13│14│15│16│17│ │15│16│17│18│19│20│21│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │19│20│21│22│23│24│25│ │16│17│18│19│20│21│22│ │16│17│18│19│20│21│22│ │20│21│22│23│24│25│26│ │18│19│20│21│22│23│24│ │22│23│24│25│26│27│28│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │26│27│28│29│30│31│ │ │23│24│25│26│27│28│ │ │23│24│25│26│27│28│29│ │27│28│29│30│ │ │ │ │25│26│27│28│29│30│31│ │29│30│ │ │ │ │ │ └──┴──┴──┴──┴──┴──┴──┘ └──┴──┴──┴──┴──┴──┴──┘ ├──┼──┼──┼──┼──┼──┼──┤ └──┴──┴──┴──┴──┴──┴──┘ └──┴──┴──┴──┴──┴──┴──┘ └──┴──┴──┴──┴──┴──┴──┘ │30│31│ │ │ │ │ │ └──┴──┴──┴──┴──┴──┴──┘ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐ │ July 1969 │ │ August 1969 │ │ September 1969 │ │ October 1969 │ │ November 1969 │ │ December 1969 │ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ │Su Mo Tu We Th Fr Sa│ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ ├──┬──┬──┬──┬──┬──┬──┤ │ │ │ 1│ 2│ 3│ 4│ 5│ │ │ │ │ │ │ 1│ 2│ │ │ 1│ 2│ 3│ 4│ 5│ 6│ │ │ │ │ 1│ 2│ 3│ 4│ │ │ │ │ │ │ │ 1│ │ │ 1│ 2│ 3│ 4│ 5│ 6│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │ 6│ 7│ 8│ 9│10│11│12│ │ 3│ 4│ 5│ 6│ 7│ 8│ 9│ │ 7│ 8│ 9│10│11│12│13│ │ 5│ 6│ 7│ 8│ 9│10│11│ │ 2│ 3│ 4│ 5│ 6│ 7│ 8│ │ 7│ 8│ 9│10│11│12│13│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │13│14│15│16│17│18│19│ │10│11│12│13│14│15│16│ │14│15│16│17│18│19│20│ │12│13│14│15│16│17│18│ │ 9│10│11│12│13│14│15│ │14│15│16│17│18│19│20│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │20│21│22│23│24│25│26│ │17│18│19│20│21│22│23│ │21│22│23│24│25│26│27│ │19│20│21│22│23│24│25│ │16│17│18│19│20│21│22│ │21│22│23│24│25│26│27│ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┼──┤ │27│28│29│30│31│ │ │ │24│25│26│27│28│29│30│ │28│29│30│ │ │ │ │ │26│27│28│29│30│31│ │ │23│24│25│26│27│28│29│ │28│29│30│31│ │ │ │ └──┴──┴──┴──┴──┴──┴──┘ ├──┼──┼──┼──┼──┼──┼──┤ └──┴──┴──┴──┴──┴──┴──┘ └──┴──┴──┴──┴──┴──┴──┘ ├──┼──┼──┼──┼──┼──┼──┤ └──┴──┴──┴──┴──┴──┴──┘ │31│ │ │ │ │ │ │ │30│ │ │ │ │ │ │ └──┴──┴──┴──┴──┴──┴──┘ └──┴──┴──┴──┴──┴──┴──┘ ,-~~-.___. / ()=(() \ ( ( 0 \._\, ,----' ##XXXxxxxxxx / ---'~; / /~|- =( ~~ | /~~~~~~~~~~~~~~~~~~~~~\ /_______________________\ /_________________________\ /___________________________\ |____________________| |____________________| |____________________| | |  ## Ruby Date class, from the standard library, knows how many days in a month, and which day is Sunday, for both Julian and Gregorian calendars. This program uses Date class, plus its own assumptions, to create the calendar. This program assumes that every year has 12 months and starts with January 1, and every month fits in 6 weeks starting with Sunday. require 'date' # Creates a calendar of _year_. Returns this calendar as a multi-line# string fit to _columns_.def cal(year, columns) # Start at January 1. # # Date::ENGLAND marks the switch from Julian calendar to Gregorian # calendar at 1752 September 14. This removes September 3 to 13 from # year 1752. (By fortune, it keeps January 1.) # date = Date.new(year, 1, 1, Date::ENGLAND) # Collect calendars of all 12 months. months = (1..12).collect do |month| rows = [Date::MONTHNAMES[month].center(20), "Su Mo Tu We Th Fr Sa"] # Make array of 42 days, starting with Sunday. days = [] date.wday.times { days.push " " } while date.month == month days.push("%2d" % date.mday) date += 1 end (42 - days.length).times { days.push " " } days.each_slice(7) { |week| rows.push(week.join " ") } next rows end # Calculate months per row (mpr). # 1. Divide columns by 22 columns per month, rounded down. (Pretend # to have 2 extra columns; last month uses only 20 columns.) # 2. Decrease mpr if 12 months would fit in the same months per # column (mpc). For example, if we can fit 5 mpr and 3 mpc, then # we use 4 mpr and 3 mpc. mpr = (columns + 2).div 22 mpr = 12.div((12 + mpr - 1).div mpr) # Use 20 columns per month + 2 spaces between months. width = mpr * 22 - 2 # Join months into calendar. rows = ["[Snoopy]".center(width), "#{year}".center(width)] months.each_slice(mpr) do |slice| slice[0].each_index do |i| rows.push(slice.map {|a| a[i]}.join " ") end end return rows.join("\n")end ARGV.length == 1 or abort "usage: #{$0} year" # Guess width of terminal.#  1. Obey environment variable COLUMNS.#  2. Try to require 'io/console' from Ruby 1.9.3.#  3. Try to run tput co.#  4. Assume 80 columns.columns = begin Integer(ENV["COLUMNS"] || "")          rescue            begin require 'io/console'; IO.console.winsize[1]            rescue LoadError              begin Integer(tput cols)              rescue                80; end; end; end puts cal(Integer(ARGV[0]), columns)

Here is 1969 in 132 columns.

$ruby cal.rb 1969 [Snoopy] 1969 January February March April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 1 2 3 4 5 1 2 3 1 2 3 4 5 6 7 5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8 6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15 13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22 20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29 27 28 29 30 25 26 27 28 29 30 31 29 30 30 31 July August September October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 1 2 1 2 3 4 5 6 1 2 3 4 1 1 2 3 4 5 6 6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13 13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 22 23 24 25 26 27 27 28 29 30 31 24 25 26 27 28 29 30 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 28 29 30 31 31 30  The output in 80 columns for the Gregorian reform year (note missing days in september):  [Snoopy] 1752 January February March Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 7 5 6 7 8 9 10 11 2 3 4 5 6 7 8 8 9 10 11 12 13 14 12 13 14 15 16 17 18 9 10 11 12 13 14 15 15 16 17 18 19 20 21 19 20 21 22 23 24 25 16 17 18 19 20 21 22 22 23 24 25 26 27 28 26 27 28 29 30 31 23 24 25 26 27 28 29 29 30 31 April May June Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 2 1 2 3 4 5 6 5 6 7 8 9 10 11 3 4 5 6 7 8 9 7 8 9 10 11 12 13 12 13 14 15 16 17 18 10 11 12 13 14 15 16 14 15 16 17 18 19 20 19 20 21 22 23 24 25 17 18 19 20 21 22 23 21 22 23 24 25 26 27 26 27 28 29 30 24 25 26 27 28 29 30 28 29 30 31 July August September Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 14 15 16 5 6 7 8 9 10 11 2 3 4 5 6 7 8 17 18 19 20 21 22 23 12 13 14 15 16 17 18 9 10 11 12 13 14 15 24 25 26 27 28 29 30 19 20 21 22 23 24 25 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 29 30 31 October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 1 2 3 4 1 2 8 9 10 11 12 13 14 5 6 7 8 9 10 11 3 4 5 6 7 8 9 15 16 17 18 19 20 21 12 13 14 15 16 17 18 10 11 12 13 14 15 16 22 23 24 25 26 27 28 19 20 21 22 23 24 25 17 18 19 20 21 22 23 29 30 31 26 27 28 29 30 24 25 26 27 28 29 30 31  ## Scala Library: Scala ### Scala Version 1 import java.util.{ Calendar, GregorianCalendar }import language.postfixOpsimport collection.mutable.ListBuffer object CalendarPrint extends App { val locd = java.util.Locale.getDefault() val cal = new GregorianCalendar val monthsMax = cal.getMaximum(Calendar.MONTH) def JDKweekDaysToISO(dn: Int) = { val nday = dn - Calendar.MONDAY if (nday < 0) (dn + Calendar.THURSDAY) else nday } def daysInMonth(year: Int, monthMinusOne: Int): Int = { cal.set(year, monthMinusOne, 1) cal.getActualMaximum(Calendar.DAY_OF_MONTH) } def namesOfMonths() = { def f1(i: Int): String = { cal.set(2013, i, 1) cal.getDisplayName(Calendar.MONTH, Calendar.LONG, locd) } (0 to monthsMax) map f1 } def offsets(year: Int): List[Int] = { val months = cal.getMaximum(Calendar.MONTH) def get1stDayOfWeek(i: Int) = { cal.set(year, i, 1) cal.get(Calendar.DAY_OF_WEEK) } (0 to monthsMax).toList map get1stDayOfWeek map { i => JDKweekDaysToISO(i) } } def headerNameOfDays() = { val mdow = cal.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.SHORT, locd) // map days of week val it = mdow.keySet.iterator val keySet = new ListBuffer[String] while (it.hasNext) keySet += it.next (keySet.map { key => (JDKweekDaysToISO(mdow.get(key)), key.take(2)) }.sortWith(_._1 < _._1) map (_._2)).mkString(" ") } def getGregCal(year: Int) = { { def dayOfMonth(month: Int) = new Iterator[(Int, Int)] { cal.set(year, month, 1) var ldom = 0 def next() = { val res = (cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH)) ldom = res._2 cal.roll(Calendar.DAY_OF_MONTH, true) res } def hasNext() = (cal.get(Calendar.DAY_OF_MONTH) > ldom) } var ret: List[(Int, Int)] = Nil for (i <- 0 to monthsMax) ret = ret ++ (dayOfMonth(i).toSeq) (ret, offsets(year)) } } def printCalendar(calendar: (List[(Int, Int)], List[Int]), headerList: List[String] = Nil, printerWidth: Int = 80) = { val mw = 20 // month width val gwf = 2 // gap width fixed val gwm = 2 // gap width minimum val fgw = true val arr = Array.ofDim[String](6, 7) def limits(printerWidth: Int): (Int, Int, Int, Int, Int) = { val pw = if (printerWidth < 20) 20 else if (printerWidth > 300) 300 else printerWidth // months side by side, gaps sum minimum val (msbs, gsm) = { val x1 = { val c = if (pw / mw > 12) 12 else pw / mw val a = (c - 1) if (c * mw + a * gwm <= pw) c else a } match { case 5 => 4 case a if (a > 6 && a < 12) => 6 case other => other } (x1, (x1 - 1) * gwm) } def getFGW(msbs: Int, gsm: Int) = { val r = (pw - msbs * mw - gsm) / 2; (r, gwf, r) } // fixed gap width def getVGW(msbs: Int, gsm: Int) = pw - msbs * mw - gsm match { // variable gap width case a if (a < 2 * gwm) => (a / 2, gwm, a / 2) case b => { val x = (b + gsm) / (msbs + 1); (x, x, x) } } // left margin, gap width, right margin val (lm, gw, rm) = if (fgw) getFGW(msbs, gsm) else getVGW(msbs, gsm) (pw, msbs, lm, gw, rm) } // def limits( val (pw, msbs, lm, gw, rm) = limits(printerWidth) val monthsList = (0 to monthsMax).map { m => calendar._1.filter { _._1 == m } } val nom = namesOfMonths() val hnod = headerNameOfDays def fsplit(list: List[(Int, Int)]): List[String] = { def fap(p: Int) = (p / 7, p % 7) for (i <- 0 until 6) for (j <- 0 until 7) arr(i)(j) = " " for (i <- 0 until list.size) arr(fap(i + calendar._2(list(i)._1))._1)(fap(i + calendar._2(list(i)._1))._2) = f"${(list(i)._2)}%2d"      arr.toList.map(_.foldRight("")(_ + " " + _))    }    val monthsRows = monthsList.map(fsplit)     def center(s: String, l: Int): String = {      (if (s.size >= l) s      else " " * ((l - s.size) / 2) + s + " " * ((l - s.size) / 2) + " ").substring(0, l)    }     val maxMonths = monthsMax + 1     val rowblocks = (1 to maxMonths / msbs).map { i =>      (0 to 5).map { j =>        val lb = new ListBuffer[String]        val k = (i - 1) * msbs        (k to k + msbs - 1).map { l => lb += monthsRows(l)(j) }        lb      }    }     val mheaders = (1 to maxMonths / msbs).      map { i => (0 to msbs - 1).map { j => center(nom(j + (i - 1) * msbs), 20) } }    val dowheaders = (1 to maxMonths / msbs).      map { i => (0 to msbs - 1).map { j => center(hnod, 20) } }     headerList.foreach(xs => println(center(xs + '\n', pw)))    (1 to 12 / msbs).foreach { i =>      println(" " * lm + mheaders(i - 1).foldRight("")(_ + " " * gw + _))      println(" " * lm + dowheaders(i - 1).foldRight("")(_ + " " * gw + _))      rowblocks(i - 1).foreach { xs => println(" " * lm + xs.foldRight("")(_ + " " * (gw - 1) + _)) }      println    }  } //  def printCal(   printCalendar(getGregCal(1969), List("[Snoopy Picture]", "1969"))  printCalendar(getGregCal(1582), List("[Snoopy Picture]", "1582"), printerWidth = 132)}
Output:
                               [Snoopy Picture]

1969

January               February               March
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5                  1  2                  1  2
6  7  8  9 10 11 12   3  4  5  6  7  8  9   3  4  5  6  7  8  9
13 14 15 16 17 18 19  10 11 12 13 14 15 16  10 11 12 13 14 15 16
20 21 22 23 24 25 26  17 18 19 20 21 22 23  17 18 19 20 21 22 23
27 28 29 30 31        24 25 26 27 28        24 25 26 27 28 29 30
31

April                  May                   June
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5  6            1  2  3  4                     1
7  8  9 10 11 12 13   5  6  7  8  9 10 11   2  3  4  5  6  7  8
14 15 16 17 18 19 20  12 13 14 15 16 17 18   9 10 11 12 13 14 15
21 22 23 24 25 26 27  19 20 21 22 23 24 25  16 17 18 19 20 21 22
28 29 30              26 27 28 29 30 31     23 24 25 26 27 28 29
30

July                 August              September
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5  6               1  2  3   1  2  3  4  5  6  7
7  8  9 10 11 12 13   4  5  6  7  8  9 10   8  9 10 11 12 13 14
14 15 16 17 18 19 20  11 12 13 14 15 16 17  15 16 17 18 19 20 21
21 22 23 24 25 26 27  18 19 20 21 22 23 24  22 23 24 25 26 27 28
28 29 30 31           25 26 27 28 29 30 31  29 30

October               November              December
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5                  1  2   1  2  3  4  5  6  7
6  7  8  9 10 11 12   3  4  5  6  7  8  9   8  9 10 11 12 13 14
13 14 15 16 17 18 19  10 11 12 13 14 15 16  15 16 17 18 19 20 21
20 21 22 23 24 25 26  17 18 19 20 21 22 23  22 23 24 25 26 27 28
27 28 29 30 31        24 25 26 27 28 29 30  29 30 31

[Snoopy Picture]

1582

January               February               March                 April                  May                   June
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1  2  3  4  5  6  7            1  2  3  4            1  2  3  4                     1      1  2  3  4  5  6               1  2  3
8  9 10 11 12 13 14   5  6  7  8  9 10 11   5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13   4  5  6  7  8  9 10
15 16 17 18 19 20 21  12 13 14 15 16 17 18  12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20  11 12 13 14 15 16 17
22 23 24 25 26 27 28  19 20 21 22 23 24 25  19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27  18 19 20 21 22 23 24
29 30 31              26 27 28              26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31           25 26 27 28 29 30
30

July                 August              September              October               November              December
Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su  Mo Tu We Th Fr Sa Su
1         1  2  3  4  5                  1  2   1  2  3  4 15 16 17   1  2  3  4  5  6  7         1  2  3  4  5
2  3  4  5  6  7  8   6  7  8  9 10 11 12   3  4  5  6  7  8  9  18 19 20 21 22 23 24   8  9 10 11 12 13 14   6  7  8  9 10 11 12
9 10 11 12 13 14 15  13 14 15 16 17 18 19  10 11 12 13 14 15 16  25 26 27 28 29 30 31  15 16 17 18 19 20 21  13 14 15 16 17 18 19
16 17 18 19 20 21 22  20 21 22 23 24 25 26  17 18 19 20 21 22 23                        22 23 24 25 26 27 28  20 21 22 23 24 25 26
23 24 25 26 27 28 29  27 28 29 30 31        24 25 26 27 28 29 30                        29 30                 27 28 29 30 31
30 31



### Scala Version 2

Works with: Scala version 2.10.1
/** * Loosely based on the Ruby implementation. * * Focuses on immutability and Scala idioms, * while trying to remain readable and clean. */object YearCalendarApp extends App with Extras {   val defaultYear = 1752  val columns = 86   val year = args.headOption.map(_.toInt).getOrElse(defaultYear)   yearCalendarLines(year, columns).foreach(println)   def yearCalendarLines(year: Int, columns: Int): Seq[String] = {    // At least one. Divide rest columns by width + 2 spaces (separator)    val calendarsPerRow = 1 + (columns - 20) / (20 + 2)     // Use 20 columns per month + 2 spaces between months    val width = calendarsPerRow * 22 - 2     List(      "[Snoopy]".center(width),      s"${year}".center(width)) ++ // Get, group, transpose and join calendar lines allMonthCalendarLines(year).grouped(calendarsPerRow).flatMap { calGroup => calGroup.transpose.map(stringsInRow => stringsInRow.mkString(" ")) } } def allMonthCalendarLines(year: Int): Seq[Seq[String]] = { (1 to 12).map { monthNr => val date = MonthCalendar(monthInYear = monthNr, year) // Make array of 42 days (7 * 6 weeks max.) starting with Sunday (which is 0) val daySlotsInMonth = { (Seq().padTo(date.dayOfWeek, " ") ++ date.daysInMonth.map { dayNr => "%2d".format(dayNr) }). padTo(42, " ") } List( date.monthName.center(20), "Su Mo Tu We Th Fr Sa") ++ daySlotsInMonth.grouped(7).map { weekSlots => weekSlots.mkString(" ") } } } } /** * This provides extra classes needed for the main * algorithm. */trait Extras { import java.util.Calendar import java.util.GregorianCalendar import java.text.SimpleDateFormat import java.util.Locale import scala.collection.mutable.Buffer implicit class MyString(str: String) { def center(width: Int): String = { val leftSpaces = (width / 2) - (str.length() / 2) val rightSpaces = width - (leftSpaces + str.length) (" " * leftSpaces) + str + (" " * rightSpaces) } } case class MonthCalendar(monthInYear: Int, year: Int) { private val javaCalendar = makeJavaCalendar(year, monthInYear) private def makeJavaCalendar(year: Int, monthInYear: Int): Calendar = { val calendar = new GregorianCalendar() // Actually, other countries changed already in 1582, // which is the JDK's default implementation. val gregorianDateChangeInEngland = { val d = Calendar.getInstance() d.set(1752, Calendar.SEPTEMBER, 14) d.getTime() } // For England we need to set this explicitly. calendar.setGregorianChange(gregorianDateChangeInEngland) calendar.set(Calendar.DAY_OF_MONTH, 1) calendar.set(Calendar.YEAR, year) calendar.set(Calendar.MONTH, monthInYear - 1) calendar } val monthName = javaCalendar.getDisplayName(Calendar.MONTH, Calendar.LONG, Locale.ENGLISH) val dayOfWeek = javaCalendar.get(Calendar.DAY_OF_WEEK) - 1 val daysInMonth = { val tempCal = makeJavaCalendar(year, monthInYear) val dayNumbers = Buffer[Int]() while (tempCal.get(Calendar.MONTH) == monthInYear - 1) { dayNumbers += tempCal.get(Calendar.DAY_OF_MONTH) tempCal.add(Calendar.DATE, 1) } dayNumbers } } } Sample output for 1792:  [Snoopy] 1752 January February March April Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 1 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 10 11 2 3 4 5 6 7 8 8 9 10 11 12 13 14 5 6 7 8 9 10 11 12 13 14 15 16 17 18 9 10 11 12 13 14 15 15 16 17 18 19 20 21 12 13 14 15 16 17 18 19 20 21 22 23 24 25 16 17 18 19 20 21 22 22 23 24 25 26 27 28 19 20 21 22 23 24 25 26 27 28 29 30 31 23 24 25 26 27 28 29 29 30 31 26 27 28 29 30 May June July August Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 1 2 3 4 5 6 1 2 3 4 1 3 4 5 6 7 8 9 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 10 11 12 13 14 15 16 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 17 18 19 20 21 22 23 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 24 25 26 27 28 29 30 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 31 30 31 September October November December Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 14 15 16 1 2 3 4 5 6 7 1 2 3 4 1 2 17 18 19 20 21 22 23 8 9 10 11 12 13 14 5 6 7 8 9 10 11 3 4 5 6 7 8 9 24 25 26 27 28 29 30 15 16 17 18 19 20 21 12 13 14 15 16 17 18 10 11 12 13 14 15 16 22 23 24 25 26 27 28 19 20 21 22 23 24 25 17 18 19 20 21 22 23 29 30 31 26 27 28 29 30 24 25 26 27 28 29 30 31  ## Seed7 $ include "seed7_05.s7i";  include "time.s7i"; const func string: center (in string: stri, in integer: length) is  return ("" lpad (length - length(stri)) div 2 <& stri) rpad length; const proc: printCalendar (in integer: year, in integer: cols) is func  local    var time: date is time.value;    var integer: dayOfWeek is 0;    const array string: monthNames is [] ("January", "February", "March", "April", "May", "June",        "July", "August", "September", "October", "November", "December");     var array array string: monthTable is 12 times 9 times "";    var string: str is "";    var integer: month is 0;    var integer: position is 0;    var integer: row is 0;    var integer: column is 0;    var integer: line is 0;  begin    for month range 1 to 12 do      monthTable[month][1] := " " & center(monthNames[month], 20);      monthTable[month][2] := " Mo Tu We Th Fr Sa Su";      date := date(year, month, 1);      dayOfWeek := dayOfWeek(date);      for position range 1 to 43 do        if position >= dayOfWeek and position - dayOfWeek < daysInMonth(date.year, date.month) then          str := succ(position - dayOfWeek) lpad 3;        else          str := "" lpad 3;        end if;        monthTable[month][3 + pred(position) div 7] &:= str;      end for;    end for;    writeln(center("[Snoopy Picture]", cols * 24 + 4));    writeln(center(str(year),cols * 24 + 4));    writeln;    for row range 1 to succ(11 div cols) do      for line range 1 to 9 do        for column range 1 to cols do          if pred(row) * cols + column <= 12 then            write("   " & monthTable[pred(row) * cols + column][line]);          end if;        end for;        writeln;      end for;    end for;  end func; const proc: main is func  begin    printCalendar(1969, 3);  end func;

Original source: [1]

The output of this program is:

                              [Snoopy Picture]
1969

January                 February                 March
Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su
1  2  3  4  5                    1  2                    1  2
6  7  8  9 10 11 12     3  4  5  6  7  8  9     3  4  5  6  7  8  9
13 14 15 16 17 18 19    10 11 12 13 14 15 16    10 11 12 13 14 15 16
20 21 22 23 24 25 26    17 18 19 20 21 22 23    17 18 19 20 21 22 23
27 28 29 30 31          24 25 26 27 28          24 25 26 27 28 29 30
31

April                    May                     June
Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su
1  2  3  4  5  6              1  2  3  4                       1
7  8  9 10 11 12 13     5  6  7  8  9 10 11     2  3  4  5  6  7  8
14 15 16 17 18 19 20    12 13 14 15 16 17 18     9 10 11 12 13 14 15
21 22 23 24 25 26 27    19 20 21 22 23 24 25    16 17 18 19 20 21 22
28 29 30                26 27 28 29 30 31       23 24 25 26 27 28 29
30

July                   August                September
Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su
1  2  3  4  5  6                 1  2  3     1  2  3  4  5  6  7
7  8  9 10 11 12 13     4  5  6  7  8  9 10     8  9 10 11 12 13 14
14 15 16 17 18 19 20    11 12 13 14 15 16 17    15 16 17 18 19 20 21
21 22 23 24 25 26 27    18 19 20 21 22 23 24    22 23 24 25 26 27 28
28 29 30 31             25 26 27 28 29 30 31    29 30

October                 November                December
Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su    Mo Tu We Th Fr Sa Su
1  2  3  4  5                    1  2     1  2  3  4  5  6  7
6  7  8  9 10 11 12     3  4  5  6  7  8  9     8  9 10 11 12 13 14
13 14 15 16 17 18 19    10 11 12 13 14 15 16    15 16 17 18 19 20 21
20 21 22 23 24 25 26    17 18 19 20 21 22 23    22 23 24 25 26 27 28
27 28 29 30 31          24 25 26 27 28 29 30    29 30 31



## Sidef

Translation of: Perl 6
require('DateTime') define months_per_col = 3define week_day_names = <Mo Tu We Th Fr Sa Su>define month_names = <Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec> func fmt_month (year, month) {    var str = sprintf("%-20s\n", month_names[month-1])    str += week_day_names.join(' ')+"\n"     var dt = %s<DateTime>    var date = dt.new(year => year, month => month)    var week_day = date.day_of_week    str += (week_day-1 of "  " -> join(" "))     var last_day = dt.last_day_of_month(year => year, month => month).day    for day (date.day .. last_day) {        date = dt.new(year => year, month => month, day => day)        str += " " if (week_day ~~ (2..7))        if (week_day == 8) {            str += "\n"            week_day = 1        }        str += sprintf("%2d", day)        ++week_day    }    str += " " if (week_day < 8)    str += (8-week_day of "  " -> join(" "))    str += "\n"} func fmt_year (year) {    var month_strs = 12.of {|i| fmt_month(year, i+1).lines }     var str = (' '*30 + year + "\n")    for month (0..11 by months_per_col) {        while (month_strs[month]) {            for i (1..months_per_col) {                month_strs[month + i - 1] || next                str += month_strs[month + i - 1].shift                str += ' '*3            }            str += "\n"        }        str += "\n"    }     return str} print fmt_year(ARGV ? Number(ARGV[0]) : 1969)
Output:
                              1969
Jan                    Feb                    Mar
Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su
1  2  3  4  5                   1  2                   1  2
6  7  8  9 10 11 12    3  4  5  6  7  8  9    3  4  5  6  7  8  9
13 14 15 16 17 18 19   10 11 12 13 14 15 16   10 11 12 13 14 15 16
20 21 22 23 24 25 26   17 18 19 20 21 22 23   17 18 19 20 21 22 23
27 28 29 30 31         24 25 26 27 28         24 25 26 27 28 29 30

Apr                    May                    Jun
Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su
1  2  3  4  5  6             1  2  3  4                      1
7  8  9 10 11 12 13    5  6  7  8  9 10 11    2  3  4  5  6  7  8
14 15 16 17 18 19 20   12 13 14 15 16 17 18    9 10 11 12 13 14 15
21 22 23 24 25 26 27   19 20 21 22 23 24 25   16 17 18 19 20 21 22
28 29 30               26 27 28 29 30 31      23 24 25 26 27 28 29

Jul                    Aug                    Sep
Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su
1  2  3  4  5  6                1  2  3    1  2  3  4  5  6  7
7  8  9 10 11 12 13    4  5  6  7  8  9 10    8  9 10 11 12 13 14
14 15 16 17 18 19 20   11 12 13 14 15 16 17   15 16 17 18 19 20 21
21 22 23 24 25 26 27   18 19 20 21 22 23 24   22 23 24 25 26 27 28
28 29 30 31            25 26 27 28 29 30 31   29 30

Oct                    Nov                    Dec
Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su   Mo Tu We Th Fr Sa Su
1  2  3  4  5                   1  2    1  2  3  4  5  6  7
6  7  8  9 10 11 12    3  4  5  6  7  8  9    8  9 10 11 12 13 14
13 14 15 16 17 18 19   10 11 12 13 14 15 16   15 16 17 18 19 20 21
20 21 22 23 24 25 26   17 18 19 20 21 22 23   22 23 24 25 26 27 28
27 28 29 30 31         24 25 26 27 28 29 30   29 30 31


## Tcl

Due to the prevalence of 80 column devices instead of 132 column ones, this code produces 3 months at a time instead of 4.

package require Tcl 8.5 # Produce information about the days in a month, without any assumptions about# what those days actually are.proc calMonthDays {timezone locale year month} {    set days {}    set moment [clock scan [format "%04d-%02d-00 12:00" $year$month] \	    -timezone $timezone -locale$locale -format "%Y-%m-%d %H:%M"]    while 1 {	set moment [clock add $moment 1 day] lassign [clock format$moment -timezone $timezone -locale$locale \		-format "%m %d %u"] m d dow	if {[scan $m %d] !=$month} {	    return $days } lappend days$moment [scan $d %d]$dow    }} proc calMonth {year month timezone locale} {    set dow 0    set line ""    set lines {}    foreach {t day dayofweek} [calMonthDays $timezone$locale $year$month] {	if {![llength $lines]} {lappend lines$t}	if {$dow >$dayofweek} {	    lappend lines [string trimright $line] set line "" set dow 0 } while {$dow < $dayofweek-1} { append line " " incr dow } append line [format "%2d "$day]	set dow $dayofweek } lappend lines [string trimright$line]} proc cal3Month {year month timezone locale} {    # Extract the month data    set d1 [lassign [calMonth $year$month $timezone$locale] t1]; incr month    set d2 [lassign [calMonth $year$month $timezone$locale] t2]; incr month    set d3 [lassign [calMonth $year$month $timezone$locale] t3]    # Print the header line of month names    foreach t [list $t1$t2 $t3] { set m [clock format$t -timezone $timezone -locale$locale -format "%B"]	set l [expr {10 + [string length $m]/2}] puts -nonewline [format "%-25s" [format "%*s"$l $m]] } puts "" # Print the month days foreach l1$d1 l2 $d2 l3$d3 {	puts [format "%-25s%-25s%s" $l1$l2 $l3] }} proc cal {{year ""} {timezone :localtime} {locale en}} { if {$year eq ""} {	set year [clock format [clock seconds] -format %Y]    }    puts [format "%40s" "-- $year --"] foreach m {1 4 7 10} { puts "" cal3Month$year $m$timezone \$locale    }} proc snoopy {} {    puts [format "%43s\n" {[Snoopy Picture]}]} snoopycal

Which produces this output:

                           [Snoopy Picture]

-- 2011 --

January                  February                  March
1  2         1  2  3  4  5  6         1  2  3  4  5  6
3  4  5  6  7  8  9      7  8  9 10 11 12 13      7  8  9 10 11 12 13
10 11 12 13 14 15 16     14 15 16 17 18 19 20     14 15 16 17 18 19 20
17 18 19 20 21 22 23     21 22 23 24 25 26 27     21 22 23 24 25 26 27
24 25 26 27 28 29 30     28                       28 29 30 31
31

April                     May                      June
1  2  3                        1            1  2  3  4  5
4  5  6  7  8  9 10      2  3  4  5  6  7  8      6  7  8  9 10 11 12
11 12 13 14 15 16 17      9 10 11 12 13 14 15     13 14 15 16 17 18 19
18 19 20 21 22 23 24     16 17 18 19 20 21 22     20 21 22 23 24 25 26
25 26 27 28 29 30        23 24 25 26 27 28 29     27 28 29 30
30 31

July                    August                 September
1  2  3      1  2  3  4  5  6  7               1  2  3  4
4  5  6  7  8  9 10      8  9 10 11 12 13 14      5  6  7  8  9 10 11
11 12 13 14 15 16 17     15 16 17 18 19 20 21     12 13 14 15 16 17 18
18 19 20 21 22 23 24     22 23 24 25 26 27 28     19 20 21 22 23 24 25
25 26 27 28 29 30 31     29 30 31                 26 27 28 29 30

October                  November                 December
1  2         1  2  3  4  5  6               1  2  3  4
3  4  5  6  7  8  9      7  8  9 10 11 12 13      5  6  7  8  9 10 11
10 11 12 13 14 15 16     14 15 16 17 18 19 20     12 13 14 15 16 17 18
17 18 19 20 21 22 23     21 22 23 24 25 26 27     19 20 21 22 23 24 25
24 25 26 27 28 29 30     28 29 30                 26 27 28 29 30 31
31


If a different year is chosen, it's printed…

snoopycal 1969
                           [Snoopy Picture]

-- 1969 --

January                  February                  March
1  2  3  4  5                     1  2                     1  2
6  7  8  9 10 11 12      3  4  5  6  7  8  9      3  4  5  6  7  8  9
13 14 15 16 17 18 19     10 11 12 13 14 15 16     10 11 12 13 14 15 16
20 21 22 23 24 25 26     17 18 19 20 21 22 23     17 18 19 20 21 22 23
27 28 29 30 31           24 25 26 27 28           24 25 26 27 28 29 30
31

April                     May                      June
1  2  3  4  5  6               1  2  3  4                        1
7  8  9 10 11 12 13      5  6  7  8  9 10 11      2  3  4  5  6  7  8
14 15 16 17 18 19 20     12 13 14 15 16 17 18      9 10 11 12 13 14 15
21 22 23 24 25 26 27     19 20 21 22 23 24 25     16 17 18 19 20 21 22
28 29 30                 26 27 28 29 30 31        23 24 25 26 27 28 29
30

July                    August                 September
1  2  3  4  5  6                  1  2  3      1  2  3  4  5  6  7
7  8  9 10 11 12 13      4  5  6  7  8  9 10      8  9 10 11 12 13 14
14 15 16 17 18 19 20     11 12 13 14 15 16 17     15 16 17 18 19 20 21
21 22 23 24 25 26 27     18 19 20 21 22 23 24     22 23 24 25 26 27 28
28 29 30 31              25 26 27 28 29 30 31     29 30

October                  November                 December
1  2  3  4  5                     1  2      1  2  3  4  5  6  7
6  7  8  9 10 11 12      3  4  5  6  7  8  9      8  9 10 11 12 13 14
13 14 15 16 17 18 19     10 11 12 13 14 15 16     15 16 17 18 19 20 21
20 21 22 23 24 25 26     17 18 19 20 21 22 23     22 23 24 25 26 27 28
27 28 29 30 31           24 25 26 27 28 29 30     29 30 31


The code also handles Julian/Gregorian switch dates correctly, but must be told what locale to format the switch as and for what timezone in that case. For example, Spain was one of the first countries to make the change:

snoopycal 1582 :Europe/Madrid es_ES
                           [Snoopy Picture]

-- 1582 --

enero                   febrero                   marzo
1  2  3  4  5  6  7               1  2  3  4               1  2  3  4
8  9 10 11 12 13 14      5  6  7  8  9 10 11      5  6  7  8  9 10 11
15 16 17 18 19 20 21     12 13 14 15 16 17 18     12 13 14 15 16 17 18
22 23 24 25 26 27 28     19 20 21 22 23 24 25     19 20 21 22 23 24 25
29 30 31                 26 27 28                 26 27 28 29 30 31

abril                     mayo                    junio
1         1  2  3  4  5  6                  1  2  3
2  3  4  5  6  7  8      7  8  9 10 11 12 13      4  5  6  7  8  9 10
9 10 11 12 13 14 15     14 15 16 17 18 19 20     11 12 13 14 15 16 17
16 17 18 19 20 21 22     21 22 23 24 25 26 27     18 19 20 21 22 23 24
23 24 25 26 27 28 29     28 29 30 31              25 26 27 28 29 30
30

julio                    agosto                 septiembre
1            1  2  3  4  5                     1  2
2  3  4  5  6  7  8      6  7  8  9 10 11 12      3  4  5  6  7  8  9
9 10 11 12 13 14 15     13 14 15 16 17 18 19     10 11 12 13 14 15 16
16 17 18 19 20 21 22     20 21 22 23 24 25 26     17 18 19 20 21 22 23
23 24 25 26 27 28 29     27 28 29 30 31           24 25 26 27 28 29 30
30 31

octubre                 noviembre                diciembre
1  2  3  4 15 16 17      1  2  3  4  5  6  7            1  2  3  4  5
18 19 20 21 22 23 24      8  9 10 11 12 13 14      6  7  8  9 10 11 12
25 26 27 28 29 30 31     15 16 17 18 19 20 21     13 14 15 16 17 18 19
22 23 24 25 26 27 28     20 21 22 23 24 25 26
29 30                    27 28 29 30 31


As can be seen, a Real Programmer has many intricacies to deal with!

## uBasic/4tH

The required "Snoopy" code is here. Use it when you feel like it.

Print "                      XXXX"Print "                     X    XX"Print "                    X  ***  X                XXXXX"Print "                   X  *****  X            XXX     XX"Print "                XXXX ******* XXX      XXXX          XX"Print "              XX   X ******  XXXXXXXXX                XX XXX"Print "            XX      X ****  X                           X** X"Print "           X        XX    XX     X                      X***X"Print "          X         //XXXX       X                      XXXX"Print "         X         //   X                             XX"Print "        X         //    X          XXXXXXXXXXXXXXXXXX/"Print "        X     XXX//    X          X"Print "        X    X   X     X         X"Print "        X    X    X    X        X"Print "         X   X    X    X        X                    XX"Print "         X    X   X    X        X                 XXX  XX"Print "          X    XXX      X        X               X  X X  X"Print "          X             X         X              XX X  XXXX"Print "           X             X         XXXXXXXX\\     XX   XX  X"Print "            XX            XX              X     X    X  XX"Print "              XX            XXXX   XXXXXX/     X     XXXX"Print "                XXX             XX***         X     X"Print "                   XXXXXXXXXXXXX *   *       X     X"Print "                                *---* X     X     X"Print "                               *-* *   XXX X     X"Print "                               *- *       XXX   X"Print "                              *- *X          XXX"Print "                              *- *X  X          XXX"Print "                             *- *X    X            XX"Print "                             *- *XX    X             X"Print "                            *  *X* X    X             X"Print "                            *  *X * X    X             X"Print "                           *  * X**  X   XXXX          X"Print "                           *  * X**  XX     X          X"Print "                          *  ** X** X     XX          X"Print "                          *  **  X*  XXX   X         X"Print "                         *  **    XX   XXXX       XXX"Print "                        *  * *      XXXX      X     X"Print "                       *   * *          X     X     X"Print "         =======*******   * *           X     X      XXXXXXXX\\"Print "                *         * *      /XXXXX      XXXXXXXX\\      )"Print "           =====**********  *     X                     )  \\  )"Print "             ====*         *     X               \\  \\   )XXXXX"Print "        =========**********       XXXXXXXXXXXXXXXXXXXXXX"

This is the code that generates the calendar:

Input "Year to print: "; Y             ' input required year Push 63 : Gosub _Space                 ' center yearPrint Y For M = 1 To 7 Step 6                  ' two rows of six months  Print   For C = 0 To 5                       ' print months    Push 1, M + C, Y : Gosub _FnMjd : @(C+6) = Pop()     Push 5 : Gosub _Space              ' print month name    Gosub (M + C)     If C = 5 Then                      ' is it the last month?      Print                            ' if so, terminate line    Else                               ' if not, print eight spaces      Push 8 : Gosub _Space    EndIf  Next   For C = 0 To 5                       ' print days header    Print "Su Mo Tu We Th Fr Sa";     If C = 5 Then                      ' is it the last month?      Print                            ' if so, terminate line    Else                               ' if not, print two spaces      Push 2 : Gosub _Space    EndIf                                       ' get days/month    Push M + C, Y : Gosub _FnDim : @(C+12) = Pop()    @(C) = 1                           ' initialize array while we're at it  Next   C =  0                               ' no columns printed yet  Q =  0                               ' keep track of position   Do                                   ' get day of the week    Push @(C+6) : Gosub _FnDow : Z = Pop ()     If @(C) - 1 < @(C + 12) Then                                       ' if a position requested BEFORE       If (Z*3 + C*22) < Q Then        ' the current position          Print                        ' then terminate the line          Q = 0                        ' and reset the counter       Endif                                       ' goto required position on screen       Push (Z*3 + C*22) - Q : Gosub _Space       Q = Z*3 + C*22                  ' set counter to that position        If @(C) < 10 Then               ' if only one digit date          Print " ";                   ' then compensate       Endif        Print @(C);                     ' print the date       Q = Q + 2                       ' and update the position        @(C) = @(C) + 1       @(C+6) = @(C+6) + 1    Endif                                       ' increment columns,    If (Z = 6) + (@(C)>@(C+12)) Then   ' wrap around if required       C = (C + 1) % 6    EndIf                                       ' loop until all dates are printed    Until (@(0)>@(0+12))*(@(1)>@(1+12))*(@(2)>@(2+12))*(@(3)>@(3+12))*(@(4)>@(4+12))*(@(5)>@(5+12))  Loop   Print                                ' terminate row with LFNext End                                        ' convert D/M/Y to Julian date_FnMjd                                 ' (day month year -- julian date)  R = Pop()                            ' pop year  S = Pop() - 3                        ' pop month  T = Pop()                            ' pop day   If S < 0 Then                        ' if month negative    S = S + 12                         ' add 12 months    R = R - 1                          ' and subtract a year  Endif   Push T + (153*S+2)/5 + R*365 + R/4 - R/100 + R/400 - 678882Return                                        ' calculate day of the week_FnDow                                 ' (julian -- day-of-week)  Push (Pop()+2400002)%7               ' convert julian date to day of weekReturn                                        ' calculate days in month_FnDim                                 ' (month year -- #days)  R = Pop()                            ' pop year  S = Pop()                            ' pop month   If S = 2 Then                        ' if February, get no. days    Push 28 + ((R%4)=0) - ((R%100)=0) + ((R%400)=0)  Else                                 ' otherwise, either 30 or 31    If (S = 4) + (S = 6) + (S = 9) + (S = 11) Then      Push 30    Else      Push 31    Endif  EndifReturn                                        ' print a number of spaces_Space                                 ' (#spaces --)  For X = 1 To Pop()                   ' print n spaces    Print " ";  NextReturn                                        ' month name subroutines001 Print " January "; : Return        ' all have a fixed length002 Print " February"; : Return        ' which simplifies things003 Print "  March  "; : Return004 Print "  April  "; : Return005 Print "   May   "; : Return006 Print "  June   "; : Return007 Print "  July   "; : Return008 Print " August  "; : Return009 Print "September"; : Return010 Print " October "; : Return011 Print " November"; : Return012 Print " December"; : Return

Output (missing Snoopy):

Year to print: 1969
1969

January               February               March                 April                  May                  June
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1                     1         1  2  3  4  5               1  2  3   1  2  3  4  5  6  7
5  6  7  8  9 10 11   2  3  4  5  6  7  8   2  3  4  5  6  7  8   6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14
12 13 14 15 16 17 18   9 10 11 12 13 14 15   9 10 11 12 13 14 15  13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21
19 20 21 22 23 24 25  16 17 18 19 20 21 22  16 17 18 19 20 21 22  20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28
26 27 28 29 30 31     23 24 25 26 27 28     23 24 25 26 27 28 29  27 28 29 30           25 26 27 28 29 30 31  29 30
30 31

July                 August               September              October               November              December
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2      1  2  3  4  5  6            1  2  3  4                     1      1  2  3  4  5  6
6  7  8  9 10 11 12   3  4  5  6  7  8  9   7  8  9 10 11 12 13   5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13
13 14 15 16 17 18 19  10 11 12 13 14 15 16  14 15 16 17 18 19 20  12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20
20 21 22 23 24 25 26  17 18 19 20 21 22 23  21 22 23 24 25 26 27  19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27
27 28 29 30 31        24 25 26 27 28 29 30  28 29 30              26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31
31                                                                30

0 OK, 0:2753

## UNIX Shell

All Unix variations come with the cal command which makes the task very easy.

 #!/bin/shecho "Snoopy goes here"cal 1969 

Output produced:

Snoopy goes here
1969

January               February               March
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1                     1
5  6  7  8  9 10 11   2  3  4  5  6  7  8   2  3  4  5  6  7  8
12 13 14 15 16 17 18   9 10 11 12 13 14 15   9 10 11 12 13 14 15
19 20 21 22 23 24 25  16 17 18 19 20 21 22  16 17 18 19 20 21 22
26 27 28 29 30 31     23 24 25 26 27 28     23 24 25 26 27 28 29
30 31
April                  May                   June
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5               1  2  3   1  2  3  4  5  6  7
6  7  8  9 10 11 12   4  5  6  7  8  9 10   8  9 10 11 12 13 14
13 14 15 16 17 18 19  11 12 13 14 15 16 17  15 16 17 18 19 20 21
20 21 22 23 24 25 26  18 19 20 21 22 23 24  22 23 24 25 26 27 28
27 28 29 30           25 26 27 28 29 30 31  29 30

July                 August              September
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2      1  2  3  4  5  6
6  7  8  9 10 11 12   3  4  5  6  7  8  9   7  8  9 10 11 12 13
13 14 15 16 17 18 19  10 11 12 13 14 15 16  14 15 16 17 18 19 20
20 21 22 23 24 25 26  17 18 19 20 21 22 23  21 22 23 24 25 26 27
27 28 29 30 31        24 25 26 27 28 29 30  28 29 30
31
October               November              December
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
1  2  3  4                     1      1  2  3  4  5  6
5  6  7  8  9 10 11   2  3  4  5  6  7  8   7  8  9 10 11 12 13
12 13 14 15 16 17 18   9 10 11 12 13 14 15  14 15 16 17 18 19 20
19 20 21 22 23 24 25  16 17 18 19 20 21 22  21 22 23 24 25 26 27
26 27 28 29 30 31     23 24 25 26 27 28 29  28 29 30 31
30


## Vedit macro language

This implementation uses the calendar.vdm macro that comes with Vedit. (So it serves as an example of how to call other macros from a macro.) See CALENDAR task for a stand-alone version.
Calendar.vdm draws one month calendar. That is then copied as columnar block and pasted to the 1969 calendar.

Buf_Switch(Buf_Free)Config_Tab(5,30,55)#9 = 1                  // first day of week: 0=Su, 1=Mo#3 = 3                  // number of months per line#2 = 1969               // year#1 = 1                  // starting monthRepeat(12/#3) {    Repeat (#3) {        Buf_Switch(Buf_Free)        Call_File(122, "calendar.vdm", "DRAW_CALENDAR")        Reg_Copy_Block(10, 1, EOB_Pos, COLSET, 1, 21)        Buf_Quit(OK)        EOL Ins_Char(9)        #5 = Cur_Pos        Reg_Ins(10)        Goto_Pos(#5)        #1++    }    EOF    Ins_Newline(2)} 

The code above creates calendar for 80x43 display. For 132 column display, change #3 (number of months per line) to 4 or 6, and adjust the tab positions if required. The following would work with all widhts, but the left/right margin would not be balanced.

Config_Tab(22)

Output:

        January   1969           February  1969           March     1969

Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su
--------------------     --------------------     --------------------
1  2  3  4  5                     1  2                     1  2
6  7  8  9 10 11 12      3  4  5  6  7  8  9      3  4  5  6  7  8  9
13 14 15 16 17 18 19     10 11 12 13 14 15 16     10 11 12 13 14 15 16
20 21 22 23 24 25 26     17 18 19 20 21 22 23     17 18 19 20 21 22 23
27 28 29 30 31           24 25 26 27 28           24 25 26 27 28 29 30
31

April     1969           May       1969           June      1969

Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su
--------------------     --------------------     --------------------
1  2  3  4  5  6               1  2  3  4                        1
7  8  9 10 11 12 13      5  6  7  8  9 10 11      2  3  4  5  6  7  8
14 15 16 17 18 19 20     12 13 14 15 16 17 18      9 10 11 12 13 14 15
21 22 23 24 25 26 27     19 20 21 22 23 24 25     16 17 18 19 20 21 22
28 29 30                 26 27 28 29 30 31        23 24 25 26 27 28 29
30

July      1969           August    1969           September 1969

Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su
--------------------     --------------------     --------------------
1  2  3  4  5  6                  1  2  3      1  2  3  4  5  6  7
7  8  9 10 11 12 13      4  5  6  7  8  9 10      8  9 10 11 12 13 14
14 15 16 17 18 19 20     11 12 13 14 15 16 17     15 16 17 18 19 20 21
21 22 23 24 25 26 27     18 19 20 21 22 23 24     22 23 24 25 26 27 28
28 29 30 31              25 26 27 28 29 30 31     29 30

October   1969           November  1969           December  1969

Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su
--------------------     --------------------     --------------------
1  2  3  4  5                     1  2      1  2  3  4  5  6  7
6  7  8  9 10 11 12      3  4  5  6  7  8  9      8  9 10 11 12 13 14
13 14 15 16 17 18 19     10 11 12 13 14 15 16     15 16 17 18 19 20 21
20 21 22 23 24 25 26     17 18 19 20 21 22 23     22 23 24 25 26 27 28
27 28 29 30 31           24 25 26 27 28 29 30     29 30 31


## XLISP

Targets the 132-column imaginary line printer. The day of the week on 1 January of a given year is found using Gauss's algorithm; LEAP-YEARP is taken from the Rosetta Code task on leap years.

(defun calendar (year)    (define months-list '(("JANUARY" 31) ("FEBRUARY" 28) ("MARCH" 31) ("APRIL" 30) ("MAY" 31) ("JUNE" 30) ("JULY" 31) ("AUGUST" 31) ("SEPTEMBER" 30) ("OCTOBER" 31) ("NOVEMBER" 30) ("DECEMBER" 31)))    (define days #("      Sunday            " "Monday            " "Tuesday           " "Wednesday         " "Thursday          " "Friday            " "Saturday"))    (defun gauss-algorithm (a)        (rem (+ 1 (+ (* 5 (rem (- a 1) 4)) (* 4 (rem (- a 1) 100)) (* 6 (rem (- a 1) 400)))) 7))    (defun range (start end)        (if (<= start end)            (cons start (range (+ start 1) end))))    (defun string-repeat (s n)        (if (= n 0)            ""            (string-append s (string-repeat s (- n 1)))))    (defun print-month (number-of-days start-day)        (defun print-days (day day-of-week end-day)            (if (= day-of-week 7)                (begin                    (newline)                    (define day-of-week 0)))            (display (string-repeat " " 8))            (if (= day-of-week 0)                (display (string-repeat " " 6)))            (if (< day 10)                (display " "))            (display day)            (display (string-repeat " " 8))            (if (= day end-day)                (begin                    (fresh-line)                    (+ day-of-week 1))                (print-days (+ day 1) (+ day-of-week 1) end-day)))        (mapcar (lambda (n) (display (vector-ref days n))) (range 0 6))        (newline)        (display (string-repeat (string-repeat " " 18) start-day))        (print-days 1 start-day number-of-days))    (defun leap-yearp (y)        (and (= (mod year 4) 0) (or (/= (mod year 100) 0) (= (mod year 400) 0))))    (define months (make-table))    (mapcar (lambda (month) (table-set! months (car month) (cadr month))) months-list)    (if (leap-yearp year)        (table-set! months "FEBRUARY" 29))    (defun print-calendar (calendar-months weekday)        (newline)        (newline)        (display (string-repeat " " 60))        (display (caar calendar-months))        (newline)        (define next-month-starts (print-month (table-ref months (caar calendar-months)) weekday))        (if (cdr calendar-months)            (print-calendar (cdr calendar-months) next-month-starts)))    (display (string-repeat " " 60))    (display "******** SNOOPY CALENDAR ")    (display year)    (display " ********")    (newline)    (newline)    (print-calendar months-list (gauss-algorithm year))) (calendar 1969)
Output:
                                                            ******** SNOOPY CALENDAR 1969 ********

JANUARY
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4
5                 6                 7                 8                 9                10                11
12                13                14                15                16                17                18
19                20                21                22                23                24                25
26                27                28                29                30                31

FEBRUARY
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1
2                 3                 4                 5                 6                 7                 8
9                10                11                12                13                14                15
16                17                18                19                20                21                22
23                24                25                26                27                28

MARCH
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1
2                 3                 4                 5                 6                 7                 8
9                10                11                12                13                14                15
16                17                18                19                20                21                22
23                24                25                26                27                28                29
30                31

APRIL
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4                 5
6                 7                 8                 9                10                11                12
13                14                15                16                17                18                19
20                21                22                23                24                25                26
27                28                29                30

MAY
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3
4                 5                 6                 7                 8                 9                10
11                12                13                14                15                16                17
18                19                20                21                22                23                24
25                26                27                28                29                30                31

JUNE
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday

1                 2                 3                 4                 5                 6                 7
8                 9                10                11                12                13                14
15                16                17                18                19                20                21
22                23                24                25                26                27                28
29                30

JULY
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4                 5
6                 7                 8                 9                10                11                12
13                14                15                16                17                18                19
20                21                22                23                24                25                26
27                28                29                30                31

AUGUST
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2
3                 4                 5                 6                 7                 8                 9
10                11                12                13                14                15                16
17                18                19                20                21                22                23
24                25                26                27                28                29                30
31

SEPTEMBER
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4                 5                 6
7                 8                 9                10                11                12                13
14                15                16                17                18                19                20
21                22                23                24                25                26                27
28                29                30

OCTOBER
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4
5                 6                 7                 8                 9                10                11
12                13                14                15                16                17                18
19                20                21                22                23                24                25
26                27                28                29                30                31

NOVEMBER
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1
2                 3                 4                 5                 6                 7                 8
9                10                11                12                13                14                15
16                17                18                19                20                21                22
23                24                25                26                27                28                29
30

DECEMBER
Sunday            Monday            Tuesday           Wednesday         Thursday          Friday            Saturday
1                 2                 3                 4                 5                 6
7                 8                 9                10                11                12                13
14                15                16                17                18                19                20
21                22                23                24                25                26                27
28                29                30                31        

## XPL0

include c:\cxpl\codes;          \intrinsic 'code' declarations func WeekDay(Year, Month, Day); \Return day of week (0=Sun 1=Mon..6=Sat)int  Year, Month, Day;          \Works for years from 1583 onward[if Month<=2 then [Month:= Month+12;  Year:= Year-1];return rem((Day-1 + (Month+1)*26/10 + Year + Year/4 + Year/100*6 + Year/400)/7);]; proc Space(N);                  \Display N space charactersint  N;while N do [ChOut(0, ^ );  N:= N-1]; proc Calendar(Year);            \Display calendar for specified yearint  Year;int  Month, Col, C, Line, MoName, Days, DayMax, Day(3);[MoName:= [  " January ", " February", "  March  ", "  April  ", "   May   ", "   June  ",  "   July  ", "  August ", "September", "  October", " November", " December"];Space(35);  Text(0, "[Snoopy]");  CrLf(0);Space(37);  IntOut(0, Year);  CrLf(0);CrLf(0);for Month:= 1 to 12 do  [for Col:= 0 to 3-1 do    [Space(5);  Text(0, MoName(Month+Col-1));  Space(7);    if Col<2 then Space(8);    ];  CrLf(0);  for Col:= 0 to 3-1 do    [Text(0, "Su Mo Tu We Th Fr Sa");    if Col<2 then Space(9);    ];  CrLf(0);  for Col:= 0 to 3-1 do         \day of first Sunday of month (can be negative)    Day(Col):= 1 - WeekDay(Year, Month+Col, 1);  for Line:= 0 to 6-1 do    [for Col:= 0 to 3-1 do      [Days:= [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];      DayMax:= Days(Month+Col);      if Month+Col=2 & (rem(Year/4)=0 & rem(Year/100)#0 ! rem(Year/400)=0) then        DayMax:= DayMax+1;      \if February and leap year then add a day      for C:= 0 to 7-1 do        [if Day(Col)>=1 & Day(Col)<=DayMax then          [IntOut(0, Day(Col));          if Day(Col)<10 then Space(1); \left justify          ]        else Space(2);          \suppress out of range days        Space(1);        Day(Col):= Day(Col)+1;        ];      if Col<2 then Space(8);      ];    CrLf(0);    ];  CrLf(0);  Month:= Month+2;              \2+1 months per Col(umn)  ];]; Calendar(1969)
Output:
                                   [Snoopy]
1969

January                      February                      March
Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa
1  2  3  4                            1                            1
5  6  7  8  9  10 11         2  3  4  5  6  7  8          2  3  4  5  6  7  8
12 13 14 15 16 17 18         9  10 11 12 13 14 15         9  10 11 12 13 14 15
19 20 21 22 23 24 25         16 17 18 19 20 21 22         16 17 18 19 20 21 22
26 27 28 29 30 31            23 24 25 26 27 28            23 24 25 26 27 28 29
30 31

April                         May                          June
Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa
1  2  3  4  5                      1  2  3          1  2  3  4  5  6  7
6  7  8  9  10 11 12         4  5  6  7  8  9  10         8  9  10 11 12 13 14
13 14 15 16 17 18 19         11 12 13 14 15 16 17         15 16 17 18 19 20 21
20 21 22 23 24 25 26         18 19 20 21 22 23 24         22 23 24 25 26 27 28
27 28 29 30                  25 26 27 28 29 30 31         29 30

July                        August                     September
Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa
1  2  3  4  5                         1  2             1  2  3  4  5  6
6  7  8  9  10 11 12         3  4  5  6  7  8  9          7  8  9  10 11 12 13
13 14 15 16 17 18 19         10 11 12 13 14 15 16         14 15 16 17 18 19 20
20 21 22 23 24 25 26         17 18 19 20 21 22 23         21 22 23 24 25 26 27
27 28 29 30 31               24 25 26 27 28 29 30         28 29 30
31

October                     November                     December
Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa         Su Mo Tu We Th Fr Sa
1  2  3  4                            1             1  2  3  4  5  6
5  6  7  8  9  10 11         2  3  4  5  6  7  8          7  8  9  10 11 12 13
12 13 14 15 16 17 18         9  10 11 12 13 14 15         14 15 16 17 18 19 20
19 20 21 22 23 24 25         16 17 18 19 20 21 22         21 22 23 24 25 26 27
26 27 28 29 30 31            23 24 25 26 27 28 29         28 29 30 31
30


## zkl

Gregorian calender only. Hard coded to a fit on a 80x43 terminal (somewhat half assed).

var [const] D=Time.Date, days="Su Mo Tu We Th Fr Sa"; fcn center(text,m) { String(" "*((m-text.len())/2),text) } fcn oneMonth(year,month){   day1:=D.zeller(year,month,1);    //1969-1-1 -->3 (Wed, ISO 8601)   dayz:=D.daysInMonth(year,month); //1969-1   -->31   List(center(D.monthNames[month],days.len()),days).extend(      (1).pump(dayz,(0).pump(day1,List,T(Void,""))).apply("%2s ".fmt)      .pump(List,T(Void.Read,days.len()/3,False),String.create));} const M=70;	// mystery numberfcn oneYear(y=1969,title="3 Days of Peace & Music"){   println(center(title,M),"\n",center(y.toString(),M),"\n");   [1..12,3].pump(String,'wrap(m){  // 3 months per line      mmm:=(m).pump(3,List,oneMonth.fp(y)); //L(L(7-8 lines), L(...), L(...))      if(mmm.apply("len").sum() % 3)  // months have diff # of lines, pad	 mmm=mmm.apply("append","");      Utils.zipWith("%-25s%-25s%-25s\n".fmt,           mmm.xplode()).concat() + (if (m<D.October) "\n" else "")   })} if(vm.numArgs){ y:=vm.nthArg(0).toInt(); oneYear(y,"").println(); }else oneYear().println();

oneMonth produces a list of strings that make up a one month calender. Each day is three characters, the first line is padded with blanks to line it up with the 1st day of the week. The entire month is one long list of "days" that is then chunked into a list of weeks (one line per week). oneYear takes 3 months and builds the page line by line.

Output:
                      3 Days of Peace & Music
1969

January                  February                  March
Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa
1  2  3  4                        1                        1
5  6  7  8  9 10 11      2  3  4  5  6  7  8      2  3  4  5  6  7  8
12 13 14 15 16 17 18      9 10 11 12 13 14 15      9 10 11 12 13 14 15
19 20 21 22 23 24 25     16 17 18 19 20 21 22     16 17 18 19 20 21 22
26 27 28 29 30 31        23 24 25 26 27 28        23 24 25 26 27 28 29
30 31

April                     May                      June
Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa
1  2  3  4  5                  1  2  3      1  2  3  4  5  6  7
6  7  8  9 10 11 12      4  5  6  7  8  9 10      8  9 10 11 12 13 14
13 14 15 16 17 18 19     11 12 13 14 15 16 17     15 16 17 18 19 20 21
20 21 22 23 24 25 26     18 19 20 21 22 23 24     22 23 24 25 26 27 28
27 28 29 30              25 26 27 28 29 30 31     29 30

July                    August                 September
Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa
1  2  3  4  5                     1  2         1  2  3  4  5  6
6  7  8  9 10 11 12      3  4  5  6  7  8  9      7  8  9 10 11 12 13
13 14 15 16 17 18 19     10 11 12 13 14 15 16     14 15 16 17 18 19 20
20 21 22 23 24 25 26     17 18 19 20 21 22 23     21 22 23 24 25 26 27
27 28 29 30 31           24 25 26 27 28 29 30     28 29 30
31

October                  November                 December
Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa
1  2  3  4                        1         1  2  3  4  5  6
5  6  7  8  9 10 11      2  3  4  5  6  7  8      7  8  9 10 11 12 13
12 13 14 15 16 17 18      9 10 11 12 13 14 15     14 15 16 17 18 19 20
19 20 21 22 23 24 25     16 17 18 19 20 21 22     21 22 23 24 25 26 27
26 27 28 29 30 31        23 24 25 26 27 28 29     28 29 30 31
30
`