Day of the week
From Rosetta Code
Day of the week is a programming task. Visitors like you are encouraged to solve it according to the task description, using any language they may happen to 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.
[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 Ada.Calendar.Year_Number loop -- 1901..2399
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;
Sample output:
1904-12-25 00:00:00 1910-12-25 00:00:00 1921-12-25 00:00:00 1927-12-25 00:00:00 1932-12-25 00:00:00 1938-12-25 00:00:00 1949-12-25 00:00:00 1955-12-25 00:00:00 1960-12-25 00:00:00 1966-12-25 00:00:00 1977-12-25 00:00:00 1983-12-25 00:00:00 1988-12-25 00:00:00 1994-12-25 00:00:00 2005-12-25 00:00:00 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 2129-12-25 00:00:00 2135-12-25 00:00:00 2140-12-25 00:00:00 2146-12-25 00:00:00 2157-12-25 00:00:00 2163-12-25 00:00:00 2168-12-25 00:00:00 2174-12-25 00:00:00 2185-12-25 00:00:00 2191-12-25 00:00:00 2196-12-25 00:00:00 2203-12-25 00:00:00 2208-12-25 00:00:00 2214-12-25 00:00:00 2225-12-25 00:00:00 2231-12-25 00:00:00 2236-12-25 00:00:00 2242-12-25 00:00:00 2253-12-25 00:00:00 2259-12-25 00:00:00 2264-12-25 00:00:00 2270-12-25 00:00:00 2281-12-25 00:00:00 2287-12-25 00:00:00 2292-12-25 00:00:00 2298-12-25 00:00:00 2304-12-25 00:00:00 2310-12-25 00:00:00 2321-12-25 00:00:00 2327-12-25 00:00:00 2332-12-25 00:00:00 2338-12-25 00:00:00 2349-12-25 00:00:00 2355-12-25 00:00:00 2360-12-25 00:00:00 2366-12-25 00:00:00 2377-12-25 00:00:00 2383-12-25 00:00:00 2388-12-25 00:00:00 2394-12-25 00:00:00
[edit] ALGOL 68
Works with: ALGOL 68 version Standard - no extensions to language used Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386 Works with: ELLA ALGOL 68 version Any (with appropriate job cards) - tested with release 1.8.8d.fc9.i386
main:(
# 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
);
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] AutoHotkey
year = 2008
stop = 2121
While year <= stop {
FormatTime, day,% year 1225, dddd
If day = Sunday
out .= year "`n"
year++
}
MsgBox,% out
[edit] C
#include <stdio.h>
#include <time.h>
#include <string.h>
int main()
{
struct tm mytime;
int i;
time_t m;
for(i=2008; i<=2121; i++)
{
memset(&mytime, 0, sizeof(struct tm));
mytime.tm_mday = 25;
mytime.tm_mon = 11;
mytime.tm_year = i-1900;
m = mktime(&mytime);
if ( m < 0 ) {
printf("%d is the last year we can specify\n", i-1);
break;
}
if ( mytime.tm_wday == 0 )
{
printf("25 December %d is Sunday\n", i);
}
}
}
The output of a run on a 32 bit machine is
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] 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 ;
}
This produces the following 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 = (from day in
(from year in Enumerable.Range(2008, 2121 - 2007)
select new DateTime(year, 12, 25))
where day.DayOfWeek == DayOfWeek.Sunday
select day.ToString("dd MMM yyyy")).ToArray();
foreach (string day in days) Console.WriteLine(day);
}
}
This looks better:
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);
}
}
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] D
I'm sure this can be done better. If anyone wants to take the time, please improve it.
import std.date;
import std.stdio;
void main() {
for(long year = 2008;year<=2121;year++)
if (0 == WeekDay(parse("December 25, "~std.string.toString(year))))
writefln("Christmas comes on a sunday in %d",year);
}
[edit] Factor
2008 2121 [a,b] [ 12 25 <date> sunday? ] filter .
[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
: zeller ( m -- days since March 1 )
9 + 12 mod 1- 26 10 */ 3 + ;
: weekday ( d m y -- 0..6 ) \ Monday..Sunday
over 3 < if 1- then
dup 4 /
over 100 / -
over 400 / + +
swap zeller + +
1+ 7 mod ;
: yuletide
." December 25 is Sunday in "
2122 2008 do
25 12 i weekday
6 = 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
[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
INTEGER, INTENT(IN) :: d, m, y
j = y / 100
k = MOD(y, 100)
Day_of_week = MOD(d + (m+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] 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] J
load 'dates' NB. provides verb 'weekday'
SunDec25=: #~ 0&=@:weekday@:(|:@,: ,. 12 25$~#,2:)
SunDec25 2008 + i.114
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
[edit] Java
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class Yuletide{
public static void main(String[] args) {
for(int i = 2008;i<=2121;i++){
Calendar cal = new GregorianCalendar(i, Calendar.DECEMBER,
25);
if(cal.get(Calendar.DAY_OF_WEEK)==Calendar.SUNDAY){
System.out.println(cal.getTime());
}
}
}
}
Output:
Sun Dec 25 00:00:00 CST 2011 Sun Dec 25 00:00:00 CST 2016 Sun Dec 25 00:00:00 CST 2022 Sun Dec 25 00:00:00 CST 2033 Sun Dec 25 00:00:00 CST 2039 Sun Dec 25 00:00:00 CST 2044 Sun Dec 25 00:00:00 CST 2050 Sun Dec 25 00:00:00 CST 2061 Sun Dec 25 00:00:00 CST 2067 Sun Dec 25 00:00:00 CST 2072 Sun Dec 25 00:00:00 CST 2078 Sun Dec 25 00:00:00 CST 2089 Sun Dec 25 00:00:00 CST 2095 Sun Dec 25 00:00:00 CST 2101 Sun Dec 25 00:00:00 CST 2107 Sun Dec 25 00:00:00 CST 2112 Sun Dec 25 00:00:00 CST 2118
[edit] JavaScript
for (var year = 2008; year <= 2121; year++) {
var yule = new Date(year, 11, 25);
if (yule.getDay() == 0)
try {
WScript.Echo(yule); // WSH
} catch(err) {
print(yule); // Rhino
}
}
output:
Sun Dec 25 00:00:00 EST 2011 Sun Dec 25 00:00:00 EST 2016 Sun Dec 25 00:00:00 EST 2022 Sun Dec 25 00:00:00 EST 2033 Sun Dec 25 00:00:00 EST 2039 Sun Dec 25 00:00:00 EST 2044 Sun Dec 25 00:00:00 EST 2050 Sun Dec 25 00:00:00 EST 2061 Sun Dec 25 00:00:00 EST 2067 Sun Dec 25 00:00:00 EST 2072 Sun Dec 25 00:00:00 EST 2078 Sun Dec 25 00:00:00 EST 2089 Sun Dec 25 00:00:00 EST 2095 Sun Dec 25 00:00:00 EST 2101 Sun Dec 25 00:00:00 EST 2107 Sun Dec 25 00:00:00 EST 2112 Sun Dec 25 00:00:00 EST 2118
[edit] M4
divert(-1)
define(`for',
`ifelse($#,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] 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] Objective-C
Works with: GNUstep
It should works also with Cocoa and OpenStep in general, but I can't test these.
#import <Foundation/Foundation.h>
int main()
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSUInteger i;
for(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);
}
[d release];
}
[pool release];
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 _ -> ()
The output of a run on a 32 bit machine is
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] 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 $i is Sunday\n";
}
}
exit 0;
Output:
25 Dec 2011 is Sunday 25 Dec 2016 is Sunday 25 Dec 2022 is Sunday 25 Dec 2033 is Sunday 25 Dec 2039 is Sunday 25 Dec 2044 is Sunday 25 Dec 2050 is Sunday 25 Dec 2061 is Sunday 25 Dec 2067 is Sunday 25 Dec 2072 is Sunday 25 Dec 2078 is Sunday 25 Dec 2089 is Sunday 25 Dec 2095 is Sunday 25 Dec 2101 is Sunday 25 Dec 2107 is Sunday 25 Dec 2112 is Sunday 25 Dec 2118 is Sunday
[edit] PHP
<?php
for($i=2008; $i<2121; $i++)
{
$datetime = new DateTime("$i-12-25 00:00:00");
if ( $datetime->format("w") == 0 )
{
echo "25 Dec $i is Sunday\n";
}
}
?>
Output:
25 Dec 2011 is Sunday 25 Dec 2016 is Sunday 25 Dec 2022 is Sunday 25 Dec 2033 is Sunday 25 Dec 2039 is Sunday 25 Dec 2044 is Sunday 25 Dec 2050 is Sunday 25 Dec 2061 is Sunday 25 Dec 2067 is Sunday 25 Dec 2072 is Sunday 25 Dec 2078 is Sunday 25 Dec 2089 is Sunday 25 Dec 2095 is Sunday 25 Dec 2101 is Sunday 25 Dec 2107 is Sunday 25 Dec 2112 is Sunday 25 Dec 2118 is Sunday
[edit] PicoLisp
(for (Y 2008 (>= 2121 Y) (inc Y))
(when (= "Sunday" (day (date Y 12 25)))
(printsp Y) ) )
Output:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
[edit] PL/I
declare i picture '9999';
do i = 2008 to 2121;
if weekday(days('25Dec' || i, 'DDMmmYYYY')) = 1 then
put skip list ('Christmas day ' || i || ' is a Sunday');
end;
[edit] PowerShell
2008..2121 | Where-Object { ([DateTime] "$_-12-25").DayOfWeek -eq "Sunday" }
[edit] Python
import datetimeOutput:
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()
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
[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
do year = 2008 to 2121
if date('w', year'1225', 's') = 'Sunday' then say year
end
Alternative:
do year = 2008 to 2121
if date('b', year'1225', 's') // 7 = 6 then say year
end
Output from either:
2011 2016 2022 2033 2039 2044 2050 2061 2067 2072 2078 2089 2095 2101 2107 2112 2118
[edit] Ruby
require 'date'
SUNDAY = 0
for year in 2008..2121
day = Date.new(year, 12, 25)
if day.wday == SUNDAY
puts '25 Dec %d' % year
end
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
The Time class overflows at the Unix epoch in 2038:
SUNDAY = 0
for year in 2008..2121
begin
day = Time.local(year, 12, 25)
if day.wday == SUNDAY
puts '25 Dec %d' % year
end
rescue ArgumentError
puts '%d is the last year we can specify' % (year-1)
break
end
end
Output on 32-bit machine:
25 Dec 2011 25 Dec 2016 25 Dec 2022 25 Dec 2033 2037 is the last year we can specify
[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 $y is a sunday"
}
}
outputs
xmas 2011 is a sunday xmas 2016 is a sunday xmas 2022 is a sunday xmas 2033 is a sunday xmas 2039 is a sunday xmas 2044 is a sunday xmas 2050 is a sunday xmas 2061 is a sunday xmas 2067 is a sunday xmas 2072 is a sunday xmas 2078 is a sunday xmas 2089 is a sunday xmas 2095 is a sunday xmas 2101 is a sunday xmas 2107 is a sunday xmas 2112 is a sunday xmas 2118 is a sunday
[edit] UNIX Shell
Works with: bash
#! /bin/bash
for i in `seq 2008 2121`
do
date -d "$i-12-25" |grep Sun
done
exit 0
The first lines of output (from a 32bit GNU/Linux system, 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!
[edit] Different machine/OS version (64 bit)
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] UnixPipes
Thanks to UNIX Shell implementation
seq 2008 2121 | xargs -IYEAR -n 1 date +%c -d 'Dec 25 YEAR' | grep Sun
(Output same as UNIX Shell)
[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 force.
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
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