Day of the week

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Task
Day of the week
You are encouraged to solve this task according to the task description, using any language you may know.

A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).

In what years between 2008 and 2121 will the 25th of December be a Sunday?

Using any standard date handling libraries of your programming language; compare the dates calculated with the output of other languages to discover any anomalies in the handling of dates which may be due to, for example, overflow in types used to represent dates/times similar to y2k type problems.

Contents

[edit] ABAP

report zday_of_week
data: lv_start type i value 2007,
lv_n type i value 114,
lv_date type sy-datum,
lv_weekday type string,
lv_day type c,
lv_year type n length 4.
 
write 'December 25 is a Sunday in: '.
do lv_n times.
lv_year = lv_start + sy-index.
concatenate lv_year '12' '25' into lv_date.
call function 'DATE_COMPUTE_DAY'
exporting date = lv_date
importing day = lv_day.
 
select single langt from t246 into lv_weekday
where sprsl = sy-langu and
wotnr = lv_day.
 
if lv_weekday eq 'Sunday'.
write / lv_year.
endif.
enddo.
 
Output:
December 25 is a Sunday in:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] Ada

with Ada.Calendar.Formatting;  use Ada.Calendar.Formatting;
with Ada.Text_IO; use Ada.Text_IO;
 
procedure Yuletide is
begin
for Year in 2008..2121 loop
if Day_Of_Week (Time_Of (Year, 12, 25)) = Sunday then
Put_Line (Image (Time_Of (Year, 12, 25)));
end if;
end loop;
end Yuletide;
Output:
2011-12-25 00:00:00
2016-12-25 00:00:00
2022-12-25 00:00:00
2033-12-25 00:00:00
2039-12-25 00:00:00
2044-12-25 00:00:00
2050-12-25 00:00:00
2061-12-25 00:00:00
2067-12-25 00:00:00
2072-12-25 00:00:00
2078-12-25 00:00:00
2089-12-25 00:00:00
2095-12-25 00:00:00
2101-12-25 00:00:00
2107-12-25 00:00:00
2112-12-25 00:00:00
2118-12-25 00:00:00

[edit] 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
Works with: ELLA ALGOL 68 version Any (with appropriate job cards) - tested with release 1.8-8d
# example from: http://www.xs4all.nl/~jmvdveer/algol.html - GPL #
INT sun=0 # , mon=1, tue=2, wed=3, thu=4, fri=5, sat=6 #;
 
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
);
 
test:(
print("December 25th is a Sunday in:");
FOR year FROM 2008 TO 2121 DO
INT wd = day of week(year, 12, 25);
IF wd = sun THEN print(whole(year,-5)) FI
OD;
new line(stand out)
)
 
Output:
December 25th is a Sunday in: 2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] AppleScript

set ChristmasSundays to {}
set Christmas to (current date)
set month of Christmas to December
set day of Christmas to 25
repeat with year from 2008 to 2121
set year of Christmas to year
if weekday of Christmas is Sunday then set end of ChristmasSundays to year
end repeat
ChristmasSundays

[edit] AutoHotkey

year = 2008
stop = 2121
 
While year <= stop {
FormatTime, day,% year 1225, dddd
If day = Sunday
out .= year "`n"
year++
}
MsgBox,% out

[edit] AutoIt

#include <date.au3>
Const $iSunday = 1
For $iYear = 2008 To 2121 Step 1
If $iSunday = _DateToDayOfWeek($iYear, 12, 25) Then
ConsoleWrite(StringFormat($iYear & "\n"))
EndIf
Next

[edit] AWK

 
# syntax: GAWK -f DAY_OF_THE_WEEK.AWK
# runtime does not support years > 2037 on my 32-bit Windows XP O/S
BEGIN {
for (i=2008; i<=2121; i++) {
x = strftime("%Y/%m/%d %a",mktime(sprintf("%d 12 25 0 0 0",i)))
if (x ~ /Sun/) { print(x) }
}
}
 

[edit] BBC BASIC

      INSTALL @lib$+"DATELIB"
 
FOR year% = 2008 TO 2121
IF FN_dow(FN_mjd(25, 12, year%)) = 0 THEN
PRINT "Christmas Day is a Sunday in "; year%
ENDIF
NEXT

[edit] bc

Because bc has no date library, this program uses Zeller's rule, also known as Zeller's congruence, to calculate day of week.

scale = 0
 
/*
* Returns day of week (0 to 6) for year, month m, day d in proleptic
* Gregorian calendar. Sunday is 0. Assumes y >= 1, scale = 0.
*/
define w(y, m, d) {
auto a
 
/* Calculate Zeller's congruence. */
a = (14 - m) / 12
m += 12 * a
y -= a
return ((d + (13 * m + 8) / 5 + \
y + y / 4 - y / 100 + y / 400) % 7)
}
 
for (y = 2008; y <= 2121; y++) {
/* If December 25 is a Sunday, print year. */
if (w(y, 12, 25) == 0) y
}
quit

[edit] Bracmat

Translation of: C
{ Calculate day of week in proleptic Gregorian calendar. Sunday == 0. }
( wday
= year month day adjustment mm yy
.  !arg:(?year,?month,?day)
& div$(14+-1*!month,12):?adjustment
& !month+12*!adjustment+-2:?mm
& !year+-1*!adjustment:?yy
& mod
$ (  !day
+ div$(13*!mm+-1,5)
+ !yy
+ div$(!yy,4)
+ -1*div$(!yy,100)
+ div$(!yy,400)
, 7
)
)
& 2008:?y
& whl
' ( !y:~>2121
& ( wday$(!y,12,25):0
& put$(str$(!y "-12-25\n"))
|
)
& 1+!y:?y
)
& done;
Output:
2011-12-25
2016-12-25
2022-12-25
2033-12-25
2039-12-25
2044-12-25
2050-12-25
2061-12-25
2067-12-25
2072-12-25
2078-12-25
2089-12-25
2095-12-25
2101-12-25
2107-12-25
2112-12-25
2118-12-25

[edit] C

Because of problems with various C libraries (such as time_t overflowing during 2038, or strptime() or mktime() not filling in tm_wday), this program uses Zeller's Rule to calculate day of week.

#include <stdio.h>
 
/* Calculate day of week in proleptic Gregorian calendar. Sunday == 0. */
int wday(int year, int month, int day)
{
int adjustment, mm, yy;
 
adjustment = (14 - month) / 12;
mm = month + 12 * adjustment - 2;
yy = year - adjustment;
return (day + (13 * mm - 1) / 5 +
yy + yy / 4 - yy / 100 + yy / 400) % 7;
}
 
int main()
{
int y;
 
for (y = 2008; y <= 2121; y++) {
if (wday(y, 12, 25) == 0) printf("%04d-12-25\n", y);
}
 
return 0;
}

[edit] C++

#include <boost/date_time/gregorian/gregorian.hpp>
#include <iostream>
 
int main( ) {
using namespace boost::gregorian ;
 
std::cout
<< "Yuletide holidays must be allowed in the following years:\n" ;
for ( int i = 2008 ; i < 2121 ; i++ ) {
greg_year gy = i ;
date d ( gy, Dec , 25 ) ;
if ( d.day_of_week( ) == Sunday ) {
std::cout << i << std::endl ;
}
}
std::cout << "\n" ;
return 0 ;
}
Output:
Yuletide holidays must be allowed in the following years:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] C#

using System;
 
class Program
{
static void Main(string[] args)
{
for (int i = 2008; i <= 2121; i++)
{
DateTime date = new DateTime(i, 12, 25);
if (date.DayOfWeek == DayOfWeek.Sunday)
{
Console.WriteLine(date.ToString("dd MMM yyyy"));
}
}
}
}

Using LINQ:

using System;
using System.Linq;
 
class Program
{
static void Main(string[] args)
{
string[] days = Enumerable.Range(2008, 2121 - 2007)
.Select(year => new DateTime(year, 12, 25))
.Where(day => day.DayOfWeek == DayOfWeek.Sunday)
.Select(day => day.ToString("dd MMM yyyy")).ToArray();
 
foreach (string day in days) Console.WriteLine(day);
}
}
Lambda expressions FTW:
using System;
using System.Linq;
 
class Program
{
static void Main(string[] args)
{
Enumerable.Range(2008, 113).ToList()
.ConvertAll(ent => new DateTime(ent, 12, 25))
.Where(ent => ent.DayOfWeek.Equals(DayOfWeek.Sunday)).ToList()
.ForEach(ent => Console.WriteLine(ent.ToString("dd MMM yyyy")));
}
}
Output:
25 Dec 2011
25 Dec 2016
25 Dec 2022
25 Dec 2033
25 Dec 2039
25 Dec 2044
25 Dec 2050
25 Dec 2061
25 Dec 2067
25 Dec 2072
25 Dec 2078
25 Dec 2089
25 Dec 2095
25 Dec 2101
25 Dec 2107
25 Dec 2112
25 Dec 2118

[edit] Clojure

Utilizing Java interop

 
(import '(java.util GregorianCalendar))
(defn yuletide [start end]
(filter #(= (. (new GregorianCalendar %
(. GregorianCalendar DECEMBER) 25) get (. GregorianCalendar DAY_OF_WEEK))
(. GregorianCalendar SUNDAY)) (range start (inc end))))
 
(yuletide 2008 2121)
 
(2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118)

[edit] COBOL

 
identification division.
program-id. dowtest.
data division.
working-storage section.
01 ws-inp-date pic x(08).
01 filler redefines ws-inp-date.
03 ws-inp-year pic 9(04).
01 ws-dow pic 9(05).
procedure division.
move '00001225' to ws-inp-date
perform test before
varying ws-inp-year from 2008 by +1
until ws-inp-year > 2121
call "todow" using
by reference ws-inp-date
by reference ws-dow
if ws-dow = 1 then
display 'year=' ws-inp-year
end-if
end-perform
stop run.
 
end program dowtest.
 
identification division.
program-id. todow.
environment division.
input-output section.
file-control.
data division.
file section.
working-storage section.
01 tally pic 9(05).
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(05).
linkage section.
01 lkip-date.
03 lkip-date-year pic 9(04).
03 lkip-date-month pic 9(02).
03 lkip-date-day pic 9(02).
01 lkop-dow pic 9(05).
88 lkop-sunday value 1.
procedure division using
by reference lkip-date
by reference lkop-dow
.
 
if lkip-date-month < 3
compute wms-month = lkip-date-month + 12
compute wms-year = lkip-date-year - 1
else
compute wms-month = lkip-date-month
compute wms-year = lkip-date-year
end-if
 
compute wms-sum =
( lkip-date-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 lkop-dow = function mod (wms-sum, 7) + 1
.
end program todow.
 
Output:
year=2011
year=2016
year=2022
year=2033
year=2039
year=2044
year=2050
year=2061
year=2067
year=2072
year=2078
year=2089
year=2095
year=2101
year=2107
year=2112
year=2118

[edit] CoffeeScript

december = 11 # gotta love Date APIs :)
sunday = 0
for year in [2008..2121]
xmas = new Date year, december, 25
console.log year if xmas.getDay() is sunday
one-liner:
console.log year for year in [2008...2121] when new Date(year, 11, 25).getDay() is 0
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] ColdFusion

 
<cfloop from = "2008" to = "2121" index = "i">
<cfset myDate = createDate(i, 12, 25) />
<cfif dayOfWeek(myDate) eq 1>
December 25th falls on a Sunday in <cfoutput>#i#</cfoutput><br />
</cfif>
</cfloop>
 

[edit] Common Lisp

(loop for year from 2008 upto 2121
when (= 6 (multiple-value-bind
(second minute hour date month year day-of-week dst-p tz)
(decode-universal-time (encode-universal-time 0 0 0 25 12 year))
day-of-week))
collect year)

[edit] D

void main() {
import std.stdio, std.range, std.algorithm, std.datetime;
 
writeln("Christmas comes on a Sunday in the years:\n",
iota(2008, 2122)
.filter!(y => Date(y, 12, 25).dayOfWeek == DayOfWeek.sun));
}
Output:
Christmas comes on a Sunday in the years:
[2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118]

[edit] Delphi

procedure IsXmasSunday(fromyear, toyear: integer);
var
i: integer;
TestDate: TDateTime;
outputyears: string;
begin
outputyears := '';
for i:= fromyear to toyear do
begin
TestDate := EncodeDate(i,12,25);
if dayofweek(TestDate) = 1 then
begin
outputyears := outputyears + inttostr(i) + ' ';
end;
end;
form1.label1.caption := outputyears;
end;

Procedure called with year range to test and outputs a space-delimited array of years to a label. There is no error check that fromyear < toyear, but this is easily added.

Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] ECL

//In what years between 2008 and 2121 will the 25th of December be a Sunday?
 
IMPORT STD;
 
BaseYear := 2008;
EndYear  := 2121;
 
ChristmasDay := RECORD
UNSIGNED1 DayofWeek;
UNSIGNED2 Year;
END;
 
ChristmasDay FindDate(INTEGER Ctr) := TRANSFORM
SELF.DayofWeek := (STD.Date.FromGregorianYMD((BaseYear-1) + Ctr,12,25)) % 7; //0=Sunday
SELF.Year := (BaseYear-1) + Ctr;
END;
 
YearDS := DATASET(EndYear-BaseYear,FindDate(COUNTER));
OUTPUT(YearDS(DayofWeek=0),{Year});
 
/* Outputs:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118
*/
 

This code solves a specific task, but can easily be modified as a generic function to return the DayOfWeek for any day after 1 AD.

[edit] Erlang

% Implemented by bengt kleberg
-module(yuletide).
-export([main/0, sunday_years/2]).
 
main() ->
[io:fwrite("25 December ~p is Sunday~n", [X]) || X <- sunday_years(2008, 2121)].
 
sunday_years( Start, Stop ) ->
[X || X <- lists:seq(Start, Stop), is_sunday(calendar:day_of_the_week({X, 12, 25}))].
 
is_sunday( 7 ) -> true;
is_sunday( _ ) -> false.
 
 
Output:
25 December 2011 is Sunday
25 December 2016 is Sunday
25 December 2022 is Sunday
25 December 2033 is Sunday
25 December 2039 is Sunday
25 December 2044 is Sunday
25 December 2050 is Sunday
25 December 2061 is Sunday
25 December 2067 is Sunday
25 December 2072 is Sunday
25 December 2078 is Sunday
25 December 2089 is Sunday
25 December 2095 is Sunday
25 December 2101 is Sunday
25 December 2107 is Sunday
25 December 2112 is Sunday
25 December 2118 is Sunday

[edit] Euphoria

 
--Day of the week task from Rosetta Code wiki
--User:Lnettnay
 
--In what years between 2008 and 2121 will the 25th of December be a Sunday
 
include std/datetime.e
 
datetime dt
 
for year = 2008 to 2121 do
dt = new(year, 12, 25)
if weeks_day(dt) = 1 then -- Sunday = 1
? year
end if
end for
 
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118


[edit] F#

open System
 
[ 2008 .. 2121 ]
|> List.choose (fun y -> if DateTime(y,12,25).DayOfWeek = DayOfWeek.Sunday then Some(y) else None)
|> printfn "%A"
Output:
[2011; 2016; 2022; 2033; 2039; 2044; 2050; 2061; 2067; 2072; 2078; 2089; 2095;
 2101; 2107; 2112; 2118]

[edit] Factor

USING: calendar math.ranges prettyprint sequences ;
2008 2121 [a,b] [ 12 25 <date> sunday? ] filter .

[edit] FBSL

#APPTYPE CONSOLE
 
'In what years between 2008 and 2121 will the 25th of December be a Sunday?
DIM date AS INTEGER, dayname AS STRING
FOR DIM year = 2008 TO 2121
date = year * 10000 + 1225
dayname = dateconv(date,"dddd")
IF dayname = "Sunday" THEN
PRINT "Christmas Day is on a Sunday in ", year
END IF
NEXT
PAUSE
 

[edit] Forth

Forth has only TIME&DATE, which does not give day of week. Many public Forth Julian date calculators had year-2100 problems, but this algorithm works well.

 
\ Zeller's Congruence
: weekday ( d m y -- wd) \ 1 mon..7 sun
over 3 < if 1- swap 12 + swap then
100 /mod
dup 4 / swap 2* -
swap dup 4 / + +
swap 1+ 13 5 */ + +
( in zeller 0=sat, so -2 to 0= mon, then mod, then 1+ for 1=mon)
2- 7 mod 1+ ;
 
: yuletide
." December 25 is Sunday in "
2122 2008 do
25 12 i weekday
7 = if i . then
loop cr ;
 
 
cr yuletide
December 25 is Sunday in 2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
ok
 


To show year-2100 problems with SwiftForth's provided Modified Julian Day support:

: yuletide
." December 25 is Sunday in "
2122 2008 do
25 12 i d/m/y
7 mod 0= if i . then
loop cr ;
 
cr yuletide
December 25 is Sunday in 2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2100 2106 2117

In 4tH a library is available which provides the right answer:

include lib/time.4th
 
: yuletide
." December 25 is Sunday in "
2122 2008 do
25 12 i weekday
6 = if i . then
loop cr ;
 
cr yuletide

The code is derived from "Collected Algorithms from ACM", Volume 1 Algorithms 1-220.

[edit] Fortran

Works with: Fortran version 90 and later

Based on Forth example

PROGRAM YULETIDE
 
IMPLICIT NONE
 
INTEGER :: day, year
 
WRITE(*, "(A)", ADVANCE="NO") "25th of December is a Sunday in"
DO year = 2008, 2121
day = Day_of_week(25, 12, year)
IF (day == 1) WRITE(*, "(I5)", ADVANCE="NO") year
END DO
 
CONTAINS
 
FUNCTION Day_of_week(d, m, y)
INTEGER :: Day_of_week, j, k, mm, yy
INTEGER, INTENT(IN) :: d, m, y
 
mm=m
yy=y
IF(mm.le.2) THEN
mm=mm+12
yy=yy-1
END IF
j = yy / 100
k = MOD(yy, 100)
Day_of_week = MOD(d + ((mm+1)*26)/10 + k + k/4 + j/4 + 5*j, 7)
END FUNCTION Day_of_week
 
END PROGRAM YULETIDE
Output:
 25th of December is a Sunday in 2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] GAP

Filtered([2008 .. 2121], y -> WeekDay([25, 12, y]) = "Sun");
# [ 2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118 ]
 
# A possible implementation of WeekDayAlt
 
days := ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];;
 
WeekDayAlt := function(args)
local d, m, y, k;
d := args[1];
m := args[2];
y := args[3];
if m < 3 then
m := m + 12;
y := y - 1;
fi;
k := 1 + RemInt(d + QuoInt((m + 1)*26, 10) + y + QuoInt(y, 4)
+ 6*QuoInt(y, 100) + QuoInt(y, 400) + 5, 7);
return days[k];
end;
 
Filtered([2008 .. 2121], y -> WeekDayAlt([25, 12, y]) = "Sun");
# [ 2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118 ]

[edit] Go

package main
 
import "fmt"
import "time"
 
func main() {
for year := 2008; year <= 2121; year++ {
if time.Date(year, 12, 25, 0, 0, 0, 0, time.UTC).Weekday() ==
time.Sunday {
fmt.Printf("25 December %d is Sunday\n", year)
}
}
}
Output:
25 December 2011 is Sunday
25 December 2016 is Sunday
25 December 2022 is Sunday
25 December 2033 is Sunday
25 December 2039 is Sunday
25 December 2044 is Sunday
25 December 2050 is Sunday
25 December 2061 is Sunday
25 December 2067 is Sunday
25 December 2072 is Sunday
25 December 2078 is Sunday
25 December 2089 is Sunday
25 December 2095 is Sunday
25 December 2101 is Sunday
25 December 2107 is Sunday
25 December 2112 is Sunday
25 December 2118 is Sunday

[edit] Groovy

Solution:

def yuletide = { start, stop -> (start..stop).findAll { Date.parse("yyyy-MM-dd", "${it}-12-25").format("EEE") == "Sun" } }

Test program:

println yuletide(2008, 2121)
Output:
[2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118]

[edit] Haskell

Using the time library:

import Data.Time
import Data.Time.Calendar.WeekDate
 
isXmasSunday year = wday == 7
where (_,_,wday) = toWeekDate $ fromGregorian year 12 25
 
main = mapM_ putStrLn ["25 December " ++ show year ++ " is Sunday"
| year <- [2008..2121], isXmasSunday year]
Output:
25 December 2011 is Sunday
25 December 2016 is Sunday
25 December 2022 is Sunday
25 December 2033 is Sunday
25 December 2039 is Sunday
25 December 2044 is Sunday
25 December 2050 is Sunday
25 December 2061 is Sunday
25 December 2067 is Sunday
25 December 2072 is Sunday
25 December 2078 is Sunday
25 December 2089 is Sunday
25 December 2095 is Sunday
25 December 2101 is Sunday
25 December 2107 is Sunday
25 December 2112 is Sunday
25 December 2118 is Sunday

The built-in System.Time module overflows at the Unix epoch in 2038:

import System.Time
 
isXmasSunday year = ctWDay cal == Sunday
where cal = toUTCTime $ toClockTime cal'
cal'
= CalendarTime {
ctYear = year,
ctMonth = December,
ctDay = 25,
ctHour = 0,
ctMin = 0,
ctSec = 0,
ctPicosec = 0,
ctWDay = Friday,
ctYDay = 0,
ctTZName = "",
ctTZ = 0,
ctIsDST = False
}
 
main = mapM_ putStrLn ["25 December " ++ show year ++ " is Sunday"
| year <- [2008..2121], isXmasSunday year]
Output:
on 32-bit machine:
25 December 2011 is Sunday
25 December 2016 is Sunday
25 December 2022 is Sunday
25 December 2033 is Sunday
*** Exception: user error (Time.toClockTime: invalid input)

[edit] HicEst

DO year = 1, 1000000
TIME(Year=year, MOnth=12, Day=25, TO, WeekDay=weekday)
IF( weekday == 7) WRITE(StatusBar) year
ENDDO
 
END
No anomalies detected for the first million years :-)
Dec 25 = Sunday in 
5 ... 2011 2016 2022 2033 2039 2044 2050 2061 2067
      2072 2078 2089 2095 2101 2107 2112 2118 ... 999994

[edit] Icon and Unicon

link datetime
 
procedure main()
writes("December 25th is a Sunday in: ")
every writes((dayoweek(25,12,y := 2008 to 2122)=="Sunday",y)," ")
end


datetime provides dayoweek

procedure dayoweek(day, month, year)	#: day of the week
static d_code, c_code, m_code, ml_code, y, C, M, Y
 
initial {
d_code := ["Saturday", "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]
 
c_code := table()
c_code[16] := c_code[20] := 0
c_code[17] := c_code[21] := 6
c_code[18] := c_code[22] := 4
c_code[19] := c_code[23] := 2
 
m_code := table()
m_code[1] := m_code["January"] := 1
m_code[2] := m_code["February"] := 4
m_code[3] := m_code["March"] := 4
m_code[4] := m_code["April"] := 0
m_code[5] := m_code["May"] := 2
m_code[6] := m_code["June"] := 5
m_code[7] := m_code["July"] := 0
m_code[8] := m_code["August"] := 3
m_code[9] := m_code["September"] := 6
m_code[10] := m_code["October"] := 1
m_code[11] := m_code["November"] := 4
m_code[12] := m_code["December"] := 6
 
ml_code := copy(m_code)
ml_code[1] := ml_code["January"] := 0
ml_code[2] := ml_code["February"] := 3
}
 
if year < 1600 then stop("*** can't compute day of week that far back")
if year > 2299 then stop("*** can't compute day of week that far ahead")
 
C := c_code[(year / 100) + 1]
y := year % 100
Y := (y / 12) + (y % 12) + ((y % 12) / 4)
month := integer(month)
M := if (year % 4) = 0 then ml_code[month] else m_code[month]
 
return d_code[(C + Y + M + day) % 7 + 1]
 
end
Output:
December 25th is a Sunday in: 2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] J

   load 'dates'                                    NB. provides verb 'weekday'
xmasSunday=: #~ 0 = [: weekday 12 25 ,~"1 0 ] NB. returns years where 25 Dec is a Sunday
xmasSunday 2008 + i.114 NB. check years from 2008 to 2121
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] Java

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
 
public class Yuletide{
public static void main(String[] args) {
for(int i = 2008;i<=2121;i++){
Calendar cal = new GregorianCalendar(i, Calendar.DECEMBER,
25);
if(cal.get(Calendar.DAY_OF_WEEK)==Calendar.SUNDAY){
System.out.println(cal.getTime());
}
}
}
}
Output:
Sun Dec 25 00:00:00 CST 2011
Sun Dec 25 00:00:00 CST 2016
Sun Dec 25 00:00:00 CST 2022
Sun Dec 25 00:00:00 CST 2033
Sun Dec 25 00:00:00 CST 2039
Sun Dec 25 00:00:00 CST 2044
Sun Dec 25 00:00:00 CST 2050
Sun Dec 25 00:00:00 CST 2061
Sun Dec 25 00:00:00 CST 2067
Sun Dec 25 00:00:00 CST 2072
Sun Dec 25 00:00:00 CST 2078
Sun Dec 25 00:00:00 CST 2089
Sun Dec 25 00:00:00 CST 2095
Sun Dec 25 00:00:00 CST 2101
Sun Dec 25 00:00:00 CST 2107
Sun Dec 25 00:00:00 CST 2112
Sun Dec 25 00:00:00 CST 2118

[edit] JavaScript

for (var year = 2008; year <= 2121; year++){
var xmas = new Date(year, 11, 25)
if ( xmas.getDay() === 0 )
console.log(year)
}
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] K

    wd:{(__jd x)!7}  / Julian day count, Sun=6
y@&6={wd 1225+x*10000}'y:2008+!114
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
 

[edit] Lasso

loop(-From=2008, -to=2121) => {^
local(tDate = date('12/25/' + loop_count))
#tDate->dayOfWeek == 1 ? '\r' + #tDate->format('%D') + ' is a Sunday'
^}
Output:
12/25/2011 is a Sunday
12/25/2016 is a Sunday
12/25/2022 is a Sunday
12/25/2033 is a Sunday
12/25/2039 is a Sunday
12/25/2044 is a Sunday
12/25/2050 is a Sunday
12/25/2061 is a Sunday
12/25/2067 is a Sunday
12/25/2072 is a Sunday
12/25/2078 is a Sunday
12/25/2089 is a Sunday
12/25/2095 is a Sunday
12/25/2101 is a Sunday
12/25/2107 is a Sunday
12/25/2112 is a Sunday
12/25/2118 is a Sunday

[edit] Liberty BASIC

    count = 0
for year = 2008 to 2121
dateString$="12/25/";year
dayNumber=date$(dateString$)
 
if dayNumber mod 7 = 5 then
count = count + 1
print dateString$
end if
 
next year
 
print count; " years when Christmas Day falls on a Sunday"
end

[edit] Lua

Library: LuaDate

require("date")
 
for year=2008,2121 do
if date(year, 12, 25):getweekday() == 1 then
print(year)
end
end
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] M4

divert(-1)
 
define(`for',
`ifelse($#,0,``$0'',
`ifelse(eval($2<=$3),1,
`pushdef(`$1',$2)$4`'popdef(`$1')$0(`$1',incr($2),$3,`$4')')')')
 
dnl julian day number corresponding to December 25th of given year
define(`julianxmas',
`define(`yrssince0',eval($1+4712))`'define(`noOfLpYrs',
eval((yrssince0+3)/4))`'define(`jd',
eval(365*yrssince0+noOfLpYrs-10-($1-1501)/100+($1-1201)/400+334+25-1))`'
ifelse(eval($1%4==0 && ($1%100!=0 || $1%400==0)),1,
`define(`jd',incr(jd))')`'jd')
 
divert
 
for(`yr',2008,2121,
`ifelse(eval(julianxmas(yr)%7==6),1,`yr ')')
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112
2118

[edit] Mathematica

Reap[If[DateString[{#,12,25},"DayName"]=="Sunday",Sow[#]]&/@Range[2008,2121]][[2,1]]

gives back:

{2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118}

[edit] MATLAB / Octave

  t  = datenum([[2008:2121]',repmat([12,25,0,0,0], 2121-2007, 1)]);
t = t(strmatch('Sunday', datestr(t,'dddd')), :);
datestr(t,'yyyy')
 


Output:
 ans =
  2011
  2016
  2022
  2033
  2039
  2044
  2050
  2061
  2067
  2072
  2078
  2089
  2095
  2101
  2107
  2112
  2118

[edit] Maxima

weekday(year, month, day) := block([m: month, y: year, k],
if m < 3 then (m: m + 12, y: y - 1),
k: 1 + remainder(day + quotient((m + 1)*26, 10) + y + quotient(y, 4)
+ 6*quotient(y, 100) + quotient(y, 400) + 5, 7),
['monday, 'tuesday, 'wednesday, 'thurdsday, 'friday, 'saturday, 'sunday][k]
)$
 
sublist(makelist(i, i, 2008, 2121),
lambda([y], weekday(y, 12, 25) = 'sunday));
/* [2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118] */

[edit] Modula-3

Translation of: C

Modula-3 represents time using a (safe) wrapper around the C time interface. Consequently, it suffers from the same problem as C.

MODULE Yule EXPORTS Main;
 
IMPORT IO, Fmt, Date, Time;
 
VAR date: Date.T;
time: Time.T;
 
BEGIN
FOR year := 2008 TO 2121 DO
date.day := 25;
date.month := Date.Month.Dec;
date.year := year;
 
TRY
time := Date.ToTime(date);
EXCEPT
| Date.Error =>
IO.Put(Fmt.Int(year) & " is the last year we can specify\n");
EXIT;
END;
 
date := Date.FromTime(time);
 
IF date.weekDay = Date.WeekDay.Sun THEN
IO.Put("25th of December " & Fmt.Int(year) & " is Sunday\n");
END;
END;
END Yule.
Output:
25th of December 2011 is Sunday
25th of December 2016 is Sunday
25th of December 2022 is Sunday
25th of December 2033 is Sunday
2038 is the last year we can specify

[edit] МК-61/52

П9	7	П7	1	П8	НОП	ИП8	2	2	-
1 0 / [x] П6 ИП9 + 1 8 9
9 - 3 6 5 , 2 5 * [x]
ИП8 ИП6 1 2 * - 1 4 - 3
0 , 5 9 * [x] + 2 9 +
ИП7 + П4 ИП4 7 / [x] 7 * -
x=0 64 ИП9 С/П ИП9 1 + П9 БП 06

Input: РX: starting year.

Output: the year in which Christmas falls on a Sunday. For example, enter 2008, the first result: 2018 (January 7, 2018 is Sunday).

[edit] MUMPS

Library: VA Kernel version 22.0
 
DOWHOLIDAY
 ;In what years between 2008 and 2121 will December 25 be a Sunday?
 ;Uses the VA's public domain routine %DTC (Part of the Kernel) named here DIDTC
NEW BDT,EDT,CHECK,CHKFOR,LIST,I,X,Y
 ;BDT - the beginning year to check
 ;EDT - the end year to check
 ;BDT and EDT are year offsets from the epoch date 1/1/1700
 ;CHECK - the month and day to look at
 ;CHKFOR - what day of the week to look for
 ;LIST - list of years in which the condition is true
 ;I - the year currently being checked
 ;X - the date in an "internal" format, for input to DOW^DIDTC
 ;Y - the output from DOW^DIDTC
SET BDT=308,EDT=421,CHECK="1225",CHKFOR=0,LIST=""
FOR I=BDT:1:EDT SET X=I_CHECK D DOW^DIDTC SET:(Y=0) LIST=$SELECT($LENGTH(LIST):LIST_", ",1:"")_(I+1700)
IF $LENGTH(LIST)=0 WRITE !,"There are no years that have Christmas on a Sunday in the given range."
IF $LENGTH(LIST) WRITE !,"The following years have Christmas on a Sunday: ",LIST
KILL BDT,EDT,CHECK,CHKFOR,LIST,I,X,Y
QUIT
 
Usage:
USER>D ^DOW

The following years have Christmas on a Sunday: 2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118

[edit] NetRexx

/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
 
yearRanges = [int 2008, 2121]
searchday = ''
cal = Calendar
 
loop year = yearRanges[0] to yearRanges[1]
cal = GregorianCalendar(year, Calendar.DECEMBER, 25)
dayIndex = cal.get(Calendar.DAY_OF_WEEK)
if dayIndex = Calendar.SUNDAY then searchday = searchday year
end year
 
say 'Between' yearRanges[0] 'and' yearRanges[1]', Christmas day falls on a Sunday on the following years:'
searchday = searchday.strip.changestr(' ', ',')
say ' 'searchday
 
return
 
Output:
Between 2008 and 2121, Christmas day falls on a Sunday on the following years:
  2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118

[edit] Comparison of Some Common Day-of-Week Algorithms

The following program exercises some common "Day-0f-Week" algorithms to confirm they all arrive at the same result.

/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
 
days = 'Monday Tuesday Wednesday Thursday Friday Saturday Sunday'
yearRanges = [int 2008, 2121]
 
searchday = ''
searchday['index'] = days.wordpos('Sunday')
searchday[0] = 0
 
algorithmName = ['Java Calendar', 'Zeller[1]', 'Zeller[2]', 'Sakamoto', 'Gauss', 'Keith', 'Babwani']
 
loop alg = 0 to algorithmName.length - 1
sd = searchday[0] + 1
searchday[0] = sd
searchday['agorithm', sd] = algorithmName[alg]
loop year = yearRanges[0] to yearRanges[1]
select case alg
when 0 then dayIndex = getDaynumJavaLibrary(year, 12, 25)
when 1 then dayIndex = getDaynumZellersCongruenceMethod1(year, 12, 25)
when 2 then dayIndex = getDaynumZellersCongruenceMethod2(year, 12, 25)
when 3 then dayIndex = getDaynumSakamoto(year, 12, 25)
when 4 then dayIndex = getDaynumGauss(year, 12, 25)
when 5 then dayIndex = getDaynumKeith(year, 12, 25)
when 6 then dayIndex = getDaynumBabwani(year, 12, 25)
otherwise nop
end
if dayIndex = searchday['index'] then
searchday[sd] = searchday[sd] year
end year
end alg
 
-- display results
say 'Between' yearRanges[0] 'and' yearRanges[1]', Christmas day falls on a Sunday in the following years:'
loop r_ = 1 to searchday[0]
searchday[r_] = searchday[r_].strip.changestr(' ', ',')
say searchday['agorithm', r_].right(20)':' searchday[r_]
end r_
 
return
 
-- -----------------------------------------------------------------------------
method getDaynumJavaLibrary(Year = int, Month = int, Day = int, iso = Rexx 'Y') public static binary returns int
-- The day-of-week is an integer value where 1 is Sunday, 2 is Monday, ..., and 7 is Saturday
-- For an ISO week date Day-of-Week d (1 = Monday to 7 = Sunday), use d = ((h - 1 + 6) mod 7) + 1
 
cal = Calendar
jmNumber = [ -
Calendar.JANUARY, Calendar.FEBRUARY, Calendar.MARCH, Calendar.APRIL -
, Calendar.MAY, Calendar.JUNE, Calendar.JULY, Calendar.AUGUST -
, Calendar.SEPTEMBER, Calendar.OCTOBER, Calendar.NOVEMBER, Calendar.DECEMBER -
]
 
mon = jmNumber[Month - 1]
cal = GregorianCalendar(Year, mon, Day)
h = cal.get(Calendar.DAY_OF_WEEK)
 
if 'YES'.abbrev(iso.upper, 1) then w = ((h - 1 + 6) // 7) + 1
else w = h
 
return w
 
-- -----------------------------------------------------------------------------
method getDaynumZellersCongruenceMethod1(Year = int, Month = int, Day = int, iso = Rexx 'Y') public static returns int
-- DayNum results in an integer in the range 0-6 where 0 represents Monday etc.
-- For an ISO week date add 1
 
if Month = 1 | Month = 2 then do
Month = Month + 12
Year = Year - 1
end
 
MonthFactor = 2 * Month + 3 * (Month + 1) % 5
YearFactor = Year + Year % 4 - Year % 100 + Year % 400
DayNum = (Day + MonthFactor + YearFactor) // 7
 
if 'YES'.abbrev(iso.upper, 1) then d = DayNum + 1
else d = DayNum
 
return d
 
-- -----------------------------------------------------------------------------
method getDaynumZellersCongruenceMethod2(Year = int, Month = int, Day = int, iso = Rexx 'Y') public static binary returns int
-- h is the day of the week (0 = Saturday, 1 = Sunday, 2 = Monday, ...)
-- For an ISO week date Day-of-Week d (1 = Monday to 7 = Sunday), use d = ((h + 5) mod 7) + 1
 
if Month < 3 then do
Month = Month + 12
Year = Year - 1
end
q = Day
m = Month
Y = Year
 
h = (q + ((m + 1) * 26 % 10) + Y + (Y % 4) + 6 * (Y % 100) + (Y % 400)) // 7
 
if 'YES'.abbrev(iso.upper, 1) then d = ((h + 5) // 7) + 1
else d = h
 
return d
 
-- -----------------------------------------------------------------------------
method getDaynumSakamoto(y = int, m = int, d = int, iso = Rexx 'Y') public static binary returns int
-- h is the day of the week (0 = Sunday, 1 = Monday, 2 = Tuesday...)
-- For an ISO week date Day-of-Week d (1 = Monday to 7 = Sunday), use d = ((h + 6) mod 7) + 1
 
t = [int 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4]
y = y - (m < 3)
h = (y + y % 4 - y % 100 + y % 400 + t[m - 1] + d) // 7
 
if 'YES'.abbrev(iso.upper, 1) then d = ((h + 6) // 7) + 1
else d = h
 
return d
 
-- -----------------------------------------------------------------------------
method getDaynumGauss(Year = int, Month = int, Day = int, iso = Rexx 'Y') public static binary returns int
-- W is week day (0 = Sunday, ..., 6 = Saturday)
-- For an ISO week date Day-of-Week d (1 = Monday to 7 = Sunday), use d = ((h + 6) mod 7) + 1
 
Year = Year - (Month < 3)
k = double Day
C = double Year % 100
Y = double Year // 100
m = double ((Month + 9) // 12) + 1
 
W = modulo(int (k + Math.floor(2.6 * m - 0.2) + y + Math.floor(y / 4) + Math.floor(c / 4) - 2 * c), 7)
 
if 'YES'.abbrev(iso.upper, 1) then h = ((W + 6) // 7) + 1
else h = W
 
return h
 
-- -----------------------------------------------------------------------------
method getDaynumKeith(y = int, m = int, d = int, iso = Rexx 'Y') public constant binary returns int
-- W is week day (0 = Sunday, ..., 6 = Saturday)
-- For an ISO week date Day-of-Week d (1 = Monday to 7 = Sunday), use d = ((h + 6) mod 7) + 1
 
if m < 3 then do
d = d + y
y = y - 1
end
else do
d = d + y - 2
end
 
h = (23 * m % 9 + d + 4 + y % 4 - y % 100 + y % 400) // 7
 
if 'YES'.abbrev(iso.upper, 1) then W = ((h + 6) // 7) + 1
else W = h
 
return W
 
-- -----------------------------------------------------------------------------
method getDaynumBabwani(Year = int, Month = int, Day = int, iso = Rexx 'Y') public constant binary returns int
-- return dow = Day of week: 0 = Saturday, 1 = Sunday, ... 6 = Friday
-- For an ISO week date Day-of-Week W (1 = Monday to 7 = Sunday), use W = ((dow + 5) mod 7) + 1
 
y = Year
m = Month
d = Day
 
dow = int -- dow stands for day of week
dowfg = double
fmonth = int
leap = int
 
if ((y // 100 == 0) & (y // 400 \= 0)) then -- leap function 1 for leap & 0 for non-leap
leap = 0
else if (y // 4 == 0) then
leap = 1
else
leap = 0
 
fmonth = 3 + (2 - leap) * ((m + 2) % (2 * m)) + (5 * m + m % 9) % 2 -- f(m) formula
fmonth = fmonth // 7 -- f(m) is brought in range of 0 to 6
 
century = y % 100
lastdigits = y // 100
 
dowfg = 1.25 * lastdigits + fmonth + d - 2 * (century // 4) -- function of weekday for Gregorian
dow = int dowfg // 7 -- remainder on division by 7
 
if 'YES'.abbrev(iso.upper, 1) then W = ((dow + 5) // 7) + 1
else W = dow
 
return W
 
-- -----------------------------------------------------------------------------
method modulo(N = int, D = int) inheritable static binary returns int
return (D + (N // D)) // D
 
Output:
Between 2008 and 2121, Christmas day falls on a Sunday in the following years:
       Java Calendar: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
           Zeller[1]: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
           Zeller[2]: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
            Sakamoto: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
               Gauss: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
               Keith: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118
             Babwani: 2011,2016,2022,2033,2039,2044,2050,2061,2067,2072,2078,2089,2095,2101,2107,2112,2118

[edit] Nimrod

import times
 
var timeinfo = getLocalTime getTime()
timeinfo.monthday = 25
timeinfo.month = mDec
for year in 2008..2121:
timeinfo.year = year
if getLocalTime(timeInfoToTime timeinfo).weekday == dSun:
stdout.write year," "
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118 

[edit] Objective-C

Works with: GNUstep
Works with: Cocoa
#import <Foundation/Foundation.h>
 
int main()
{
@autoreleasepool {
for(NSUInteger i=2008; i<2121; i++)
{
NSCalendarDate *d = [[NSCalendarDate alloc]
initWithYear: i
month: 12
day: 25
hour: 0 minute: 0 second:0
timeZone: [NSTimeZone timeZoneWithAbbreviation:@"CET"] ];
if ( [d dayOfWeek] == 0 )
{
printf("25 Dec %u is Sunday\n", i);
}
}
 
}
return 0;
}
Output:
25 Dec 2011 is Sunday
25 Dec 2016 is Sunday
25 Dec 2022 is Sunday
25 Dec 2033 is Sunday
25 Dec 2039 is Sunday
25 Dec 2044 is Sunday
25 Dec 2050 is Sunday
25 Dec 2061 is Sunday
25 Dec 2067 is Sunday
25 Dec 2072 is Sunday
25 Dec 2078 is Sunday
25 Dec 2089 is Sunday
25 Dec 2095 is Sunday
25 Dec 2101 is Sunday
25 Dec 2107 is Sunday
25 Dec 2112 is Sunday
25 Dec 2118 is Sunday

[edit] OCaml

Translation of: C
#load "unix.cma"
open Unix
 
try
for i = 2008 to 2121 do
(* I'm lazy so we'll just borrow the current time
instead of having to set all the fields explicitly *)

let mytime = { (localtime (time ())) with
tm_year = i - 1900;
tm_mon = 11;
tm_mday = 25 } in
try
let _, mytime = mktime mytime in
if mytime.tm_wday = 0 then
Printf.printf "25 December %d is Sunday\n" i
with e ->
Printf.printf "%d is the last year we can specify\n" (i-1);
raise e
done
with _ -> ()
Output:
of a run on a 32 bit machine
25 December 2011 is Sunday
25 December 2016 is Sunday
25 December 2022 is Sunday
25 December 2033 is Sunday
2037 is the last year we can specify

[edit] With a dedicated library

Unlike the previous example which only uses the OCaml standard library, here with the OCaml Calendar Library we can go until the year 2121:

open CalendarLib
 
let list_make_seq first last =
let rec aux i acc =
if i < first then acc
else aux (pred i) (i::acc)
in
aux last []
 
let print_date (year, month, day) =
Printf.printf "%d-%02d-%02d\n" year month day
 
let () =
let years = list_make_seq 2008 2121 in
let years = List.filter (fun year ->
Date.day_of_week (Date.make year 12 25) = Date.Sun) years in
print_endline "December 25 is a Sunday in:";
List.iter (Printf.printf "%d\n") years
Output:
$ ocaml unix.cma str.cma -I +calendar calendarLib.cma xmas_sundays.ml
December 25 is a Sunday in:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] ooRexx

 
date = .datetime~new(2008, 12, 25)
lastdate = .datetime~new(2121, 12, 25)
 
resultList = .array~new -- our collector of years
 
-- date objects are directly comparable
loop while date <= lastdate
if date~weekday == 7 then resultList~append(date~year)
-- step to the next year
date = date~addYears(1)
end
 
say "Christmas falls on Sunday in the years" resultList~toString("Line", ", ")
 

[edit] Pascal

See Delphi

[edit] Perl

#! /usr/bin/perl -w
 
use Time::Local;
use strict;
 
foreach my $i (2008 .. 2121)
{
my $time = timelocal(0,0,0,25,11,$i);
my ($s,$m,$h,$md,$mon,$y,$wd,$yd,$is) = localtime($time);
if ( $wd == 0 )
{
print "25 Dec $i is Sunday\n";
}
}
 
exit 0;
Output:
25 Dec 2011 is Sunday
25 Dec 2016 is Sunday
25 Dec 2022 is Sunday
25 Dec 2033 is Sunday
Day too big - 25195 > 24855
Sec too small - 25195 < 78352
Sec too big - 25195 > 15247
Cannot handle date (0, 0, 0, 25, 11, 2038) at ./ydate.pl line 8

Using the DateTime module from CPAN:

#! /usr/bin/perl -w
 
use DateTime;
use strict;
 
foreach my $i (2008 .. 2121)
{
my $dt = DateTime->new( year => $i,
month => 12,
day => 25
);
if ( $dt->day_of_week == 7 )
{
print "25 Dec $i is Sunday\n";
}
}
 
exit 0;

or shorter:

#! /usr/bin/perl -w
 
use DateTime;
use strict;
 
for (2008 .. 2121) {
print "25 Dec $_ is Sunday\n"
if DateTime->new(year => $_, month => 12, day => 25)->day_of_week == 7;
}
 
exit 0;
Output:
25 Dec 2011 is Sunday
25 Dec 2016 is Sunday
25 Dec 2022 is Sunday
25 Dec 2033 is Sunday
25 Dec 2039 is Sunday
25 Dec 2044 is Sunday
25 Dec 2050 is Sunday
25 Dec 2061 is Sunday
25 Dec 2067 is Sunday
25 Dec 2072 is Sunday
25 Dec 2078 is Sunday
25 Dec 2089 is Sunday
25 Dec 2095 is Sunday
25 Dec 2101 is Sunday
25 Dec 2107 is Sunday
25 Dec 2112 is Sunday
25 Dec 2118 is Sunday

Alternatively in one line using grep (read from right to left):

#! /usr/bin/perl -w
 
use DateTime;
use strict;
 
print join " ", grep { DateTime->new(year => $_, month => 12, day => 25)->day_of_week == 7 } (2008 .. 2121);
 
0;
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] Perl 6

Works with: Rakudo version 2010.07

As Perl 5, except DateTime is built-in, so you don't need to download a module of that name:

say join ' ', grep { Date.new($_, 12, 25).day-of-week == 7 }, 2008 .. 2121;

[edit] PHP

<?php
for($i=2008; $i<2121; $i++)
{
$datetime = new DateTime("$i-12-25 00:00:00");
if ( $datetime->format("w") == 0 )
{
echo "25 Dec $i is Sunday\n";
}
}
?>
Output:
25 Dec 2011 is Sunday
25 Dec 2016 is Sunday
25 Dec 2022 is Sunday
25 Dec 2033 is Sunday
25 Dec 2039 is Sunday
25 Dec 2044 is Sunday
25 Dec 2050 is Sunday
25 Dec 2061 is Sunday
25 Dec 2067 is Sunday
25 Dec 2072 is Sunday
25 Dec 2078 is Sunday
25 Dec 2089 is Sunday
25 Dec 2095 is Sunday
25 Dec 2101 is Sunday
25 Dec 2107 is Sunday
25 Dec 2112 is Sunday
25 Dec 2118 is Sunday

[edit] PicoLisp

(for (Y 2008 (>= 2121 Y) (inc Y))
(when (= "Sunday" (day (date Y 12 25)))
(printsp Y) ) )
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] Pike

filter(Calendar.Year(2008)->range(Calendar.Year(2121))->years()->month(12)->day(25), lambda(object day){ return day->week_day()==7; })->year()->format_nice();
Output:
 Result: ({ /* 17 elements */
                 "2011",
                 "2016",
                 "2022",
                 "2033",
                 "2039",
                 "2044",
                 "2050",
                 "2061",
                 "2067",
                 "2072",
                 "2078",
                 "2089",
                 "2095",
                 "2101",
                 "2107",
                 "2112",
                 "2118"
             })

[edit] PL/I

 
declare i picture '9999';
do i = 2008 to 2121;
if weekday(days('25Dec' || i, 'DDMmmYYYY')) = 1 then
put skip list ('Christmas day ' || i || ' is a Sunday');
end;
 

[edit] PowerShell

2008..2121 | Where-Object { (Get-Date $_-12-25).DayOfWeek -eq "Sunday" }

[edit] Protium

<@ SAI>
<@ ITEFORLI3>2121|2008|
<@ LETVARCAP>Christmas Day|25-Dec-<@ SAYVALFOR>...</@></@>
<@ TSTDOWVARLIT>Christmas Day|1</@>
<@ IFF>
<@ SAYCAP>Christmas Day <@ SAYVALFOR>...</@> is a Sunday</@><@ SAYKEY>__Newline</@>
</@>
</@>
</@>

English dialect variable-length space-padded opcodes

<# suppressimplicitoutput>
<# iterate foriteration literalstring3>2121|2008|
<# let variable capture>Christmas Day|25-Dec-<# say value foriteration>...</#></#>
<# test dayofweek variable literal>Christmas Day|1</#>
<# if>
<# say capture>Christmas Day <# say value foriteration>...</#> is a Sunday</#><# say keyword>__Newline</#>
</#>
</#>
 
</#>
Output:
Christmas Day 2011 is a Sunday
Christmas Day 2016 is a Sunday
Christmas Day 2022 is a Sunday
Christmas Day 2033 is a Sunday
Christmas Day 2039 is a Sunday
Christmas Day 2044 is a Sunday
Christmas Day 2050 is a Sunday
Christmas Day 2061 is a Sunday
Christmas Day 2067 is a Sunday
Christmas Day 2072 is a Sunday
Christmas Day 2078 is a Sunday
Christmas Day 2089 is a Sunday
Christmas Day 2095 is a Sunday
Christmas Day 2101 is a Sunday
Christmas Day 2107 is a Sunday
Christmas Day 2112 is a Sunday
Christmas Day 2118 is a Sunday

[edit] PureBasic

PureBasic's internal Date() is limited between 1970-01-01 00:00:00 and 2038-01-19 03:14:07

For i=2008 To 2037
If DayOfWeek(Date(i,12,25,0,0,0))=0
PrintN(Str(i))
EndIf
Next

[edit] Python

import datetime
 
def yuletide():
sunday = 6
days = (day.strftime('%d %b %Y') for day in (datetime.date(year, 12, 25) for year in range(2008,2122)) if day.weekday() == sunday)
print '\n'.join(days)
 
yuletide()
Output:
25 Dec 2011
25 Dec 2016
25 Dec 2022
25 Dec 2033
25 Dec 2039
25 Dec 2044
25 Dec 2050
25 Dec 2061
25 Dec 2067
25 Dec 2072
25 Dec 2078
25 Dec 2089
25 Dec 2095
25 Dec 2101
25 Dec 2107
25 Dec 2112
25 Dec 2118

[edit] R

years <- 2008:2121
xmas <- as.POSIXlt(paste(years, '/12/25', sep=""))
years[xmas$wday==0]
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
 
Also:
 
xmas=seq(as.Date("2008/12/25"), as.Date("2121/12/25"), by="year")
as.numeric(format(xmas[weekdays(xmas)== 'Sunday'], "%Y"))
 
#Still another solution, using ISOdate and weekdays
(2008:2121)[weekdays(ISOdate(2008:2121, 12, 25)) == "Sunday"]
 
# Simply replace "Sunday" with whatever it's named in your country,
# or set locale first, with
Sys.setlocale(cat="LC_ALL", "en")

[edit] Racket

 
#lang racket
 
(require racket/date)
 
(define (xmas-on-sunday? year)
(zero? (date-week-day (seconds->date (find-seconds 0 0 12 25 12 year)))))
 
(for ([y (in-range 2008 2121)] #:when (xmas-on-sunday? y))
(displayln y))
 

[edit] REBOL

rebol [
Title: "Yuletide Holiday"
Author: oofoe
Date: 2009-12-07
URL: http://rosettacode.org/wiki/Yuletide_Holiday
]

 
for y 2008 2121 1 [
d: to-date reduce [y 12 25]
if 7 = d/weekday [prin [y ""]]
]
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] REXX

[edit] using DATE weekday

The extended DATE parameters (arguments 2 and 3) are only supported by the newer REXX interpreters.

    do year=2008 to 2121
if date('w', year'1225', 's') == 'Sunday' then say year
end
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] using DATE base

The extended DATE parameters (arguments 2 and 3) are only supported by the newer REXX interpreters.

    do year=2008 to 2121
if date('b', year'1225', 's') // 7 == 6 then say year
end

output is the same as above

[edit] using DATE iso

The extended DATE parameters (arguments 2 and 3) are only supported by the newer REXX interpreters.

Language note: the DATE built-in function always returns the day-of-week in English, no matter what the native language is in effect.

/*REXX program displays which years  December 25th  falls on a  Sunday. */
parse arg start finish . /*get the start and finish years.*/
if start=='' then start=2008 /*None specified? Assume default*/
if finish=='' then finish=2121 /*None specified? Assume default*/
 
do y=start to finish /*process the years specified. */
 
if date('Weekday',y"-12-25",'ISO')\=='Sunday' then iterate
/* if date('w' ,y"-12-25",'i' )\== ... (same as above). */
/* option yyyy-mm-dd fmt */
 
say 'December 25th,' y "falls on a Sunday."
end /*y*/
/*stick a fork in it, we're done.*/
Output:
when using the default input
December 25th, 2011 falls on a Sunday.
December 25th, 2016 falls on a Sunday.
December 25th, 2022 falls on a Sunday.
December 25th, 2033 falls on a Sunday.
December 25th, 2039 falls on a Sunday.
December 25th, 2044 falls on a Sunday.
December 25th, 2050 falls on a Sunday.
December 25th, 2061 falls on a Sunday.
December 25th, 2067 falls on a Sunday.
December 25th, 2072 falls on a Sunday.
December 25th, 2078 falls on a Sunday.
December 25th, 2089 falls on a Sunday.
December 25th, 2095 falls on a Sunday.
December 25th, 2101 falls on a Sunday.
December 25th, 2107 falls on a Sunday.
December 25th, 2112 falls on a Sunday.
December 25th, 2118 falls on a Sunday.

[edit] old school DOW

This DOW (day-of-week) version will work with any version of a REXX interpreter.

/*REXX program (old school) displays which years 12/25 falls on a Sunday*//
 
parse arg start finish . /*get the start and finish years.*/
if start=='' then start=2008 /*None specified? Assume default*/
if finish=='' then finish=2121 /*None specified? Assume default*/
 
do y=start to finish /*process the years specified. */
if dow(12,25,y)==1 then say 'December 25th,' y "falls on a Sunday."
end /*y*/
exit /*stick a fork in it, we're done.*/
/*──────────────────────────────────DOW (day of week) subroutine────────*/
dow: 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 w /*Sunday=1, Monday=2, ... Saturday=7*/
Output:
using the default input
December 25th, 2011 falls on a Sunday.
December 25th, 2016 falls on a Sunday.
December 25th, 2022 falls on a Sunday.
December 25th, 2033 falls on a Sunday.
December 25th, 2039 falls on a Sunday.
December 25th, 2044 falls on a Sunday.
December 25th, 2050 falls on a Sunday.
December 25th, 2061 falls on a Sunday.
December 25th, 2067 falls on a Sunday.
December 25th, 2072 falls on a Sunday.
December 25th, 2078 falls on a Sunday.
December 25th, 2089 falls on a Sunday.
December 25th, 2095 falls on a Sunday.
December 25th, 2101 falls on a Sunday.
December 25th, 2107 falls on a Sunday.
December 25th, 2112 falls on a Sunday.
December 25th, 2118 falls on a Sunday.

[edit] Ruby

require 'date'
 
(2008..2121).each do |year|
puts "25 Dec #{year}" if Date.new(year, 12, 25).wday == 0 # Ruby 1.9: if Date.new(year, 12, 25).sunday?
end
Output:
25 Dec 2011
25 Dec 2016
25 Dec 2022
25 Dec 2033
25 Dec 2039
25 Dec 2044
25 Dec 2050
25 Dec 2061
25 Dec 2067
25 Dec 2072
25 Dec 2078
25 Dec 2089
25 Dec 2095
25 Dec 2101
25 Dec 2107
25 Dec 2112
25 Dec 2118

Or using the Time class

(2008..2121).each {|year| puts "25 Dec #{year}" if Time.local(year, 12, 25).sunday?}
Output:
25 Dec 2011
25 Dec 2016
25 Dec 2022
25 Dec 2033
25 Dec 2039
25 Dec 2044
25 Dec 2050
25 Dec 2061
25 Dec 2067
25 Dec 2072
25 Dec 2078
25 Dec 2089
25 Dec 2095
25 Dec 2101
25 Dec 2107
25 Dec 2112
25 Dec 2118

(Note: The Time class could not handle beyond 2038 prior to Ruby 1.9.2.[1])

[edit] Run BASIC

for year = 2008 to 2121
if val(date$("12-25-";year)) mod 7 = 5 then print "For ";year;"xmas is Sunday"
next year

For 2011 xmas is Sunday For 2016 xmas is Sunday For 2022 xmas is Sunday For 2033 xmas is Sunday For 2039 xmas is Sunday For 2044 xmas is Sunday For 2050 xmas is Sunday For 2061 xmas is Sunday For 2067 xmas is Sunday For 2072 xmas is Sunday For 2078 xmas is Sunday For 2089 xmas is Sunday For 2095 xmas is Sunday For 2101 xmas is Sunday For 2107 xmas is Sunday For 2112 xmas is Sunday For 2118 xmas is Sunday

[edit] SAS

data _null_;
do y=2008 to 2121;
a=mdy(12,25,y);
if weekday(a)=1 then put y;
end;
run;
 
/* 2011 2016 2022 2033 2039 2044 2050 2061 2067
2072 2078 2089 2095 2101 2107 2112 2118 */

[edit] Scala

Library: Scala

[edit] JDK (discouraged)

import java.util.{ Calendar, GregorianCalendar }
import Calendar.{ DAY_OF_WEEK, DECEMBER, SUNDAY }
 
object DayOfTheWeek extends App {
val years = 2008 to 2121
 
val yuletide =
years.filter(year => (new GregorianCalendar(year, DECEMBER, 25)).get(DAY_OF_WEEK) == SUNDAY)
 
// If you want a test: (optional)
assert(yuletide ==
Seq(2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061,
2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118))
 
println(yuletide.mkString(
s"${yuletide.length} Years between ${years.head} and ${years.last}" +
" including where Christmas is observed on Sunday:\n", ", ", "."))
}

[edit] JDK >= 8 (recommended)

[edit] Naive programming

import java.time.{ DayOfWeek, LocalDate }
 
object DayOfTheWeek1 extends App {
val years = 2008 to 2121
val yuletide = for {
year <- years
if LocalDate.of(year, 12, 25).getDayOfWeek() == DayOfWeek.SUNDAY
} yield year
 
println(yuletide.mkString(
s"${yuletide.count(p => true)} Years between ${years.head} and ${years.last}" +
" including where Christmas is observed on Sunday:\n", ", ", "."))
}

[edit] Idiomatic programming

import java.time.{ DayOfWeek, LocalDate }
 
object DayOfTheWeek1 extends App {
val years = 2008 to 2121
val yuletide =
years.filter(year => (LocalDate.of(year, 12, 25).getDayOfWeek() == DayOfWeek.SUNDAY))
 
// If you want a test: (optional)
assert(yuletide ==
Seq(2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061,
2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118))
 
println(yuletide.mkString(
s"${yuletide.length} Years between ${years.head} and ${years.last}" +
" including where Christmas is observed on Sunday:\n", ", ", "."))
}

[edit] Tail recursion

import java.time.{ DayOfWeek, LocalDate }
import scala.annotation.tailrec
 
object DayOfTheWeek3 extends App {
val years = 2008 to 2121
val yuletide = {
@tailrec
def inner(anni: List[Int], accu: List[Int]): List[Int] = {
if (anni == Nil) accu
else inner(anni.tail, accu ++
(if (LocalDate.of(anni.head, 12, 25).getDayOfWeek() == DayOfWeek.SUNDAY) List(anni.head)
else Nil))
}
inner(years.toList, Nil)
}
 
// If you want a test: (optional)
assert(yuletide ==
Seq(2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061,
2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118))
 
println(yuletide.mkString(
s"${yuletide.length} Years between ${years.head} and ${years.last}" +
" including where Christmas is observed on Sunday:\n", ", ", "."))
}
Output of all solutions:
Years between 2008 and 2121 including when Christmas is observed on Sunday:
2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118.

[edit] Scheme

(define (day-of-week year month day)
(if (< month 3)
(begin (set! month (+ month 12)) (set! year (- year 1))))
(+ 1
(remainder (+ 5 day (quotient (* (+ 1 month) 13) 5)
year (quotient year 4) (* (quotient year 100) 6) (quotient year 400))
7)))
 
(define (task)
(let loop ((y 2121) (v '()))
(if (< y 2008)
v
(loop (- y 1)
(if (= 7 (day-of-week y 12 25))
(cons y v)
v)))))
 
(task)
; (2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118)

[edit] Seed7

The library time.s7i defines the function dayOfWeek, which returns 1 for monday, 2 for tuesday, and so on up to 7 for sunday.

$ include "seed7_05.s7i";
include "time.s7i";
 
const proc: main is func
local
var integer: year is 0;
begin
for year range 2008 to 2122 do
if dayOfWeek(date(year, 12, 25)) = 7 then
writeln("Christmas comes on a sunday in " <& year);
end if;
end for;
end func;
Output:
Christmas comes on a sunday in 2011
Christmas comes on a sunday in 2016
Christmas comes on a sunday in 2022
Christmas comes on a sunday in 2033
Christmas comes on a sunday in 2039
Christmas comes on a sunday in 2044
Christmas comes on a sunday in 2050
Christmas comes on a sunday in 2061
Christmas comes on a sunday in 2067
Christmas comes on a sunday in 2072
Christmas comes on a sunday in 2078
Christmas comes on a sunday in 2089
Christmas comes on a sunday in 2095
Christmas comes on a sunday in 2101
Christmas comes on a sunday in 2107
Christmas comes on a sunday in 2112
Christmas comes on a sunday in 2118

[edit] Smalltalk

2008 to: 2121 do: [ :year | |date|
date := Date newDay: 25 monthIndex: 12 year: year.
date dayName = #Sunday
ifTrue: [ date displayNl ]
]
Output:
25-Dec-2011
25-Dec-2016
25-Dec-2022
25-Dec-2033
25-Dec-2039
25-Dec-2044
25-Dec-2050
25-Dec-2061
25-Dec-2067
25-Dec-2072
25-Dec-2078
25-Dec-2089
25-Dec-2095
25-Dec-2101
25-Dec-2107
25-Dec-2112
25-Dec-2118

[edit] Suneido

year = 2008
while (year <= 2121)
{
if Date('#' $ year $ '1225').WeekDay() is 0
Print(year)
++year
}
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] Tcl

Works with: Tcl version 8.5
package require Tcl 8.5
 
for {set y 2008} {$y <= 2121} {incr y} {
if {[clock format [clock scan "$y-12-25" -format {%Y-%m-%d}] -format %w] == 0} {
puts "xmas $y is a sunday"
}
}
Output:
xmas 2011 is a sunday
xmas 2016 is a sunday
xmas 2022 is a sunday
xmas 2033 is a sunday
xmas 2039 is a sunday
xmas 2044 is a sunday
xmas 2050 is a sunday
xmas 2061 is a sunday
xmas 2067 is a sunday
xmas 2072 is a sunday
xmas 2078 is a sunday
xmas 2089 is a sunday
xmas 2095 is a sunday
xmas 2101 is a sunday
xmas 2107 is a sunday
xmas 2112 is a sunday
xmas 2118 is a sunday

[edit] TI-83 BASIC

Works with TI-84+/SE only

 
:For(A, 2008,2121
:dayofWk(A,12,25
:If Ans=1
:Disp A
:End
 
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118
Done

[edit] TUSCRIPT

 
$$ MODE TUSCRIPT
PRINT "25th of December will be a Sunday in the following years: "
LOOP year=2008,2121
SET dayofweek = DATE (number,25,12,year,nummer)
IF (dayofweek==7) PRINT year
ENDLOOP
 
Output:
25th of December will be a Sunday in the following years:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] UNIX Shell

Unix commands may use time_t to count seconds since the epoch. For systems with 32-bit time, the counter overflows during 19 January 2038. These scripts continue to 2121 and may need a system with 64-bit time, to prevent the overflow.

[edit] With GNU date

This solution uses date -d, which seems to be a GNU extension, so it only works with those systems.

Works with: bash
#! /bin/bash
 
for (( i=2008; i<=2121; ++i ))
do
date -d "$i-12-25"
done |grep Sun
 
exit 0

The first lines of output (from a GNU/Linux system with 32bit time_t, date version 6.9) are

Sun Dec 25 00:00:00 CET 2011
Sun Dec 25 00:00:00 CET 2016
Sun Dec 25 00:00:00 CET 2022
Sun Dec 25 00:00:00 CET 2033
date: invalid date `2038-12-25'

I.e., starting from year 2038, the date command (which uses the glibc library, at least on GNU systems), is not able to recognise the date as a valid one!

Different machine/OS version (64 bit time_t): This is the same command run on RedHat Linux.

bash-3.00$ date --version
date (coreutils) 5.2.1
Written by David MacKenzie.
 
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
bash-3.00$ uname -a
Linux brslln01 2.6.9-67.ELsmp #1 SMP Wed Nov 7 13:56:44 EST 2007 x86_64 x86_64 x86_64 GNU/Linux
bash-3.00$ for((i=2009; i <= 2121; i++)); do date -d "$i-12-25" |egrep Sun; done
Sun Dec 25 00:00:00 GMT 2011
Sun Dec 25 00:00:00 GMT 2016
Sun Dec 25 00:00:00 GMT 2022
Sun Dec 25 00:00:00 GMT 2033
Sun Dec 25 00:00:00 GMT 2039
Sun Dec 25 00:00:00 GMT 2044
Sun Dec 25 00:00:00 GMT 2050
Sun Dec 25 00:00:00 GMT 2061
Sun Dec 25 00:00:00 GMT 2067
Sun Dec 25 00:00:00 GMT 2072
Sun Dec 25 00:00:00 GMT 2078
Sun Dec 25 00:00:00 GMT 2089
Sun Dec 25 00:00:00 GMT 2095
Sun Dec 25 00:00:00 GMT 2101
Sun Dec 25 00:00:00 GMT 2107
Sun Dec 25 00:00:00 GMT 2112
Sun Dec 25 00:00:00 GMT 2118
bash-3.00$

[edit] With GNU date and GNU seq (UnixPipes)

Like the previous solution, this solution uses date -d, which seems to be a GNU extension. Output is same as previous solution.

seq 2008 2121 | xargs -IYEAR -n 1 date +%c -d 'Dec 25 YEAR' | grep Sun

[edit] With Unix cal

The cal command is a tradition since Version 6 AT&T UNIX. This solution assumes that cal will always output a calendar in this format.

$ cal 12 2011 
   December 2011
Su Mo Tu We Th Fr Sa
             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
                    

This format always puts Sunday in columns 1 and 2. The solution uses tail to delete the first 2 lines (month, year, names of days), cut to extract Sunday's columns, and grep to check if "25" appears in those columns.

Works with: Bourne Shell
y=2008
while test $y -lt 2122; do
cal 12 $y | tail +3 | cut -c1-2 | grep -Fq 25 && echo 25 Dec $y
y=`expr $y + 1`
done

Running this script with OpenBSD, the output is identical to the C# program. OpenBSD cal accepts any year from 1 to 9999, so 2008 to 2122 is well within range.

[edit] With zsh

zmodload zsh/datetime
for (( year = 2010; year <= 2121; year++ ));
if [[ $(strftime '%A' $(strftime -r '%F' $year-12-25)) == Sunday ]] print $year

If the system has 32-bit time, this script will malfunction for years >= 2038; it will print no year from 2038 to 2121 (unless today is Sunday, then it prints every year from 2038 to 2121). This happens because strftime -r '%F' $year-12-25 yields -1 for an out-of-range date, and strftime '%A' -1 yields name of today.

[edit] Ursala

A standard library, stt, provides basic date manipulation functions, and is imported in this example. Unix era times denominated in seconds since 1969 (excluding leap seconds) are represented as natural numbers with unlimited precision. Results are valid for the arbitrarily distant future assuming the Gregorian calendar remains in effect.

The algorithm relies on the string_to_time function converting a date expressed as a character string to seconds without needing a weekday field in the input, and the time_to_string function outputting the corresponding date with the weekday included. The output is then filtered for Sundays.

#import std
#import nat
#import stt
 
christmases = time_to_string* string_to_time*TS 'Dec 25 0:0:0 '-*@hS %nP* nrange/2008 2121
 
#show+
 
sunday_years = ~&zS sep` * =]'Sun'*~ christmases
Output:
2011                            
2016                            
2022                            
2033                            
2039                            
2044                            
2050                            
2061                            
2067                            
2072                            
2078                            
2089                            
2095                            
2101                            
2107                            
2112
2118

[edit] Vedit macro language

Buf_Switch(Buf_Free)
for (#3 = 2008; #3 < 2122; #3++) {
Reg_Set(10, "12/25/")
Num_Str(#3, 10, LEFT+APPEND)
if (JDate(@10) % 7 == 0) {
Num_Ins(#3, NOCR)
}
}
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118

[edit] Wortel

!-&y = 0 `.getDay. @new Date[y 11 25] @range[2008 2121]
Returns:
[2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118]

[edit] XPL0

The original routine in the library only worked correctly between the years 1980 and 2099. It was upgraded with this new routine that handles all dates in the Gregorian calendar, from 1583 onward. It's based on Zeller's Congruence.

include c:\cxpl\codes;                  \intrinsic 'code' declarations
 
proc WeekDay(Year, Month, Day); \Return day of week (0=Sat 1=Sun..6=Fri)
int Year, Month, Day;
[if Month<=2 then [Month:= Month+12; Year:= Year-1];
return rem((Day + (Month+1)*26/10 + Year + Year/4 + Year/100*6 + Year/400) / 7);
]; \WeekDay
 
 
int Year;
[for Year:= 2008 to 2121 do
if WeekDay(Year, 12, 25) = 1 then \25th of December is a Sunday
[IntOut(0, Year); CrLf(0)];
]
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118

[edit] zkl

ISO dates, monday is 1, sunday is 7

var [const] D=Time.Date;
foreach y in ([2008..2121]){
if (D.Sunday==D.weekDay(y,12,25)) println(y)
}
Output:
2011
2016
2022
2033
2039
2044
2050
2061
2067
2072
2078
2089
2095
2101
2107
2112
2118
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