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Day of the week of Christmas and New Year

From Rosetta Code
Day of the week of Christmas and New Year is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Task


Determine programatically and show on this page on what weekday Christmas Day, 2021 and New Year's Day, 2022 will fall or did fall.

11l[edit]

Translation of: Python
V weekDays = [‘Sunday’, ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’, ‘Saturday’]
V thisXMas = Time(2021, 12, 25)
V thisXMasDay = Int(thisXMas.strftime(‘%w’))
V thisXMasDayAsString = weekDays[thisXMasDay]
print(‘This year's Christmas is on a ’thisXMasDayAsString)
 
V nextNewYear = Time(2022, 1, 1)
V nextNewYearDay = Int(nextNewYear.strftime(‘%w’))
V nextNewYearDayAsString = weekDays[nextNewYearDay]
print(‘Next new year is on a ’nextNewYearDayAsString)
Output:
This year's Christmas is on a Saturday
Next new year is on a Saturday

Ada[edit]

with Ada.Text_Io;
with Ada.Calendar.Formatting;
 
procedure Weekdays is
use Ada.Text_Io;
use Ada.Calendar.Formatting;
 
subtype Time is Ada.Calendar.Time;
 
procedure Info (Date : Time) is
begin
Put (Image (Date));
Put (" is a ");
Put (Day_Name'Image (Day_Of_Week (Date)));
Put (".");
New_Line;
end Info;
 
Christmas_Day : constant Time := Time_Of (Year => 2021, Month => 12, Day => 25);
New_Years_Day : constant Time := Time_Of (Year => 2022, Month => 01, Day => 01);
 
begin
Info (Christmas_Day);
Info (New_Years_Day);
end Weekdays;
Output:
2021-12-25 00:00:00 is a SATURDAY.
2022-01-01 00:00:00 is a SATURDAY.

ALGOL W[edit]

Re-using code from the Day of the week task.

begin % find the day of the week 25/12/2021 and 01/01/2022 fall on %
string(10) array dayName( 0 :: 6 );
integer procedure Day_of_week ( integer value d, m, y );
begin
integer j, k, mm, yy;
mm := m;
yy := y;
if mm <= 2 then begin
mm := mm + 12;
yy := yy - 1;
end if_m_le_2;
j := yy div 100;
k := yy rem 100;
(d + ( ( mm + 1 ) * 26 ) div 10 + k + k div 4 + j div 4 + 5 * j ) rem 7
end Day_of_week;
dayName( 0 ) := "Saturday"; dayName( 1 ) := "Sunday"; dayName( 2 ) := "Monday";
dayName( 3 ) := "Tuesday"; dayName( 4 ) := "Wednesday"; dayName( 5 ) := "Thursday";
dayName( 6 ) := "Friday";
write( "25th of December 2021 is a ", dayName( Day_of_week( 25, 12, 2021 ) ) );
write( " 1st of January 2022 is a ", dayName( Day_of_week( 1, 1, 2022 ) ) )
end.
Output:
25th of December 2021 is a Saturday
 1st of January  2022 is a Saturday

AWK[edit]

 
# syntax: GAWK -f WHAT_WEEKDAYS_WILL_CHRISTMAS_AND_NEW_YEAR.AWK
BEGIN {
fmt = "%Y-%m-%d is a %A"
print(strftime(fmt,mktime("2021 12 25 0 0 0")))
print(strftime(fmt,mktime("2022 01 01 0 0 0")))
print("")
fmt = "%d %b %Y is %A"
print(strftime(fmt,mktime("2021 12 25 0 0 0")))
print(strftime(fmt,mktime("2022 01 01 0 0 0")))
exit(0)
}
 
Output:
2021-12-25 is a Saturday
2022-01-01 is a Saturday

25 Dec 2021 is Saturday
01 Jan 2022 is Saturday

BASIC[edit]

10 DEFINT A-Z
20 DIM D$(6)
30 FOR I=0 TO 6: READ D$(I): NEXT
40 FOR I=1 TO 2
50 READ Y,M,D
60 PRINT USING "##/##/#### is a ";M;D;Y;
70 IF M<=2 THEN M=M+12: Y=Y-1
80 J=Y\100
90 K=Y MOD 100
100 D=(D+((M+1)*26)\10+K+K\4+J\4+5*J) MOD 7
110 PRINT D$(D)
120 NEXT
130 DATA Saturday,Sunday,Monday,Tuesday,Wednesday,Thursday,Friday
140 DATA 2021,12,25
150 DATA 2022,1,1
Output:
12/25/2021 is a Saturday
 1/ 1/2022 is a Saturday

BCPL[edit]

get "libhdr"
 
let dayofweek(y,m,d) = valof
$( let j, k = ?, ?
if m<=2
$( m := m+12
y := y-1
$)
j := y/100
k := y rem 100
d := (d + ((m+1)*26)/10 + k + k/4 + j/4 + 5*j) rem 7
switchon d into
$( case 0: resultis "Saturday"
case 1: resultis "Sunday"
case 2: resultis "Monday"
case 3: resultis "Tuesday"
case 4: resultis "Wednesday"
case 5: resultis "Thursday"
case 6: resultis "Friday"
$)
$)
 
let show(y,m,d) be
writef("%N/%N/%N is a %S*N", m, d, y, dayofweek(y, m, d))
 
let start() be
$( show(2021,12,25)
show(2022,1,1)
$)
Output:
12/25/2021 is a Saturday
1/1/2022 is a Saturday

C[edit]

#define _XOPEN_SOURCE
#include <stdio.h>
#include <time.h>
 
int main() {
struct tm t[2];
strptime("2021-12-25", "%F", &t[0]);
strptime("2022-01-01", "%F", &t[1]);
for (int i=0; i<2; i++) {
char buf[32];
strftime(buf, 32, "%F is a %A", &t[i]);
puts(buf);
}
return 0;
}
Output:
2021-12-25 is a Saturday
2022-01-01 is a Saturday

CLU[edit]

day_of_week = proc (d: date) returns (string)
own days: array[string] := array[string]$
[0:"Saturday", "Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday", "Friday"]
 
m: int := d.month
y: int := d.year
if m <= 2 then
m := m + 12
y := y - 1
end
j: int := y/100
k: int := y//100
dn: int := (d.day + ((m+1)*26)/10 + k + k/4 + j/4 + 5*j)//7
return(days[dn])
end day_of_week
 
start_up = proc ()
po: stream := stream$primary_output()
days: array[date] := array[date]$
[date$create(25, 12, 2021, 0, 0, 0),
date$create( 1, 1, 2022, 0, 0, 0)]
 
for d: date in array[date]$elements(days) do
stream$putl(po, date$unparse_date(d) || " is a " || day_of_week(d))
end
end start_up
Output:
25 December 2021 is a Saturday
1 January 2022 is a Saturday

COBOL[edit]

       IDENTIFICATION DIVISION.
PROGRAM-ID. XMASNY.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
01 WEEKDAYS.
03 DAY-NAMES.
05 FILLER PIC X(9) VALUE "Saturday ".
05 FILLER PIC X(9) VALUE "Sunday ".
05 FILLER PIC X(9) VALUE "Monday ".
05 FILLER PIC X(9) VALUE "Tuesday ".
05 FILLER PIC X(9) VALUE "Wednesday".
05 FILLER PIC X(9) VALUE "Thursday ".
05 FILLER PIC X(9) VALUE "Friday ".
03 DAYS PIC X(9) OCCURS 7 TIMES,
REDEFINES DAY-NAMES.
01 OUT-FMT.
03 OUT-MONTH PIC 99.
03 FILLER PIC X VALUE "/".
03 OUT-DAY PIC 99.
03 FILLER PIC X VALUE "/".
03 OUT-YEAR PIC 9(4).
03 FILLER PIC X(6) VALUE " is a ".
03 OUT-DAYNAME PIC X(9).
 
01 VARIABLES.
03 CDATE.
05 D-MONTH PIC 99.
05 D-DAY PIC 99.
05 D-YEAR PIC 9999.
03 ZELLER-DATA.
05 M PIC 99.
05 Y PIC 99.
05 D PIC 999.
05 D7 PIC 999.
05 J PIC 99.
05 K PIC 99.
05 DAY-NAME PIC X(9).
 
PROCEDURE DIVISION.
BEGIN.
MOVE "25122021" TO CDATE.
PERFORM SHOW-WEEKDAY.
MOVE "01012022" TO CDATE.
PERFORM SHOW-WEEKDAY.
STOP RUN.
 
SHOW-WEEKDAY.
MOVE D-MONTH TO OUT-MONTH.
MOVE D-DAY TO OUT-DAY.
MOVE D-YEAR TO OUT-YEAR.
PERFORM ZELLER.
MOVE DAY-NAME TO OUT-DAYNAME.
DISPLAY OUT-FMT.
 
ZELLER.
MOVE D-MONTH TO M.
MOVE D-YEAR TO Y.
IF M IS NOT GREATER THAN 2,
ADD 12 TO M,
SUBTRACT 1 FROM Y.
DIVIDE Y BY 100 GIVING J.
COMPUTE K = Y - J * 100.
COMPUTE D = (M + 1) * 26.
DIVIDE 10 INTO D.
ADD K TO D.
DIVIDE 4 INTO K.
ADD K TO D.
COMPUTE D = D + 5 * J.
DIVIDE 4 INTO J.
COMPUTE D = D + J + D-DAY.
DIVIDE D BY 7 GIVING D7.
MULTIPLY 7 BY D7.
COMPUTE D = D - D7 + 1.
MOVE DAYS(D) TO DAY-NAME.
Output:
25/12/2021 is a Saturday
01/01/2022 is a Saturday

Cowgol[edit]

include "cowgol.coh";
 
record Date is
year: uint16;
month: uint8;
day: uint8;
end record;
 
sub DayName(date: [Date]): (name: [uint8]) is
var days: [uint8][] := {
"Saturday", "Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday", "Friday"
};
 
var m := date.month as uint16;
var y := date.year;
var d := date.day as uint16;
 
if m <= 2 then
m := m + 12;
y := y - 1;
end if;
 
var j := y / 100;
var k := y % 100;
d := (d + ((m+1)*26)/10 + k + k/4 + j/4 + 5*j) % 7;
name := days[d as @indexof days];
end sub;
 
sub printDate(date: [Date]) is
print_i8(date.month);
print_char('/');
print_i8(date.day);
print_char('/');
print_i16(date.year);
end sub;
 
var dates: Date[] := {
{2021, 25, 12},
{2022, 1, 1}
};
 
var i: @indexof dates := 0;
while i < @sizeof dates loop
printDate(&dates[i]);
print(" is a ");
print(DayName(&dates[i]));
print_nl();
i := i + 1;
end loop;
Output:
25/12/2021 is a Saturday
1/1/2022 is a Saturday

Draco[edit]

type Date = struct {
word year;
byte month, day
};
 
proc nonrec day_name(Date date) *char:
word m, y, d, j, k;
m := date.month;
y := date.year;
d := date.day;
if m <= 2 then
m := m + 12;
y := y - 1
fi;
j := y / 100;
k := y % 100;
d := (d + ((m+1)*26)/10 + k + (k>>2) + (j>>2) + 5*j) % 7;
case d
incase 0: "Saturday"
incase 1: "Sunday"
incase 2: "Monday"
incase 3: "Tuesday"
incase 4: "Wednesday"
incase 5: "Thursday"
incase 6: "Friday"
esac
corp
 
proc nonrec print_date(Date d) void:
write(d.month, '/', d.day, '/', d.year)
corp
 
proc nonrec main() void:
[2] Date dates = ((2021, 12, 25), (2022, 1, 1));
byte i;
for i from 0 upto 1 do
print_date(dates[i]);
writeln(" is a ", day_name(dates[i]))
od
corp
Output:
12/25/2021 is a Saturday
1/1/2022 is a Saturday

F#[edit]

 
// Show day of week for Christmas Day, 2021 and New Year's Day, 2022. Nigel Galloway: December 1st., 2021
printfn $"Christmas Day 2021 is a %s{string(System.DateTime(2021,12,25).DayOfWeek)}. New Years Day 2022 is a %s{string(System.DateTime(2022,1,1).DayOfWeek)}."
 
Output:
Christmas Day 2021 is a Saturday. New Years Day 2022 is a Saturday.

Factor[edit]

Works with: Factor version 0.99 2021-06-02
USING: calendar calendar.english calendar.holidays.us formatting
kernel sequences ;
 
CONSTANT: msg
"In %d, New Years is on a %s, and Christmas is on a %s.\n"
 
: day-name ( ts -- str ) day-of-week day-names nth ;
: christmas ( n -- str ) christmas-day day-name ;
: new-years ( n -- str ) new-years-day day-name ;
: holidays ( n -- ny ch ) [ new-years ] [ christmas ] bi ;
: .holidays ( seq -- ) [ dup holidays msg printf ] each ;
 
{ 1578 1590 1642 1957 2020 2021 2022 2242 2245 2393 } .holidays
Output:
In 1578, New Years is on a Sunday, and Christmas is on a Monday.
In 1590, New Years is on a Monday, and Christmas is on a Tuesday.
In 1642, New Years is on a Wednesday, and Christmas is on a Thursday.
In 1957, New Years is on a Tuesday, and Christmas is on a Wednesday.
In 2020, New Years is on a Wednesday, and Christmas is on a Friday.
In 2021, New Years is on a Friday, and Christmas is on a Saturday.
In 2022, New Years is on a Saturday, and Christmas is on a Sunday.
In 2242, New Years is on a Saturday, and Christmas is on a Sunday.
In 2245, New Years is on a Wednesday, and Christmas is on a Thursday.
In 2393, New Years is on a Friday, and Christmas is on a Saturday.

FreeBASIC[edit]

#include "vbcompat.bi"       'contains functions for dealing with dates and times
#include "string.bi" 'contains functions for formatting text strings
 
dim as double christmas = DateSerial(2021, 12, 25) 'enter the dates of the two holidays
dim as double newyears = DateSerial(2022, 01, 01)
 
print "Christmas Day 2021 is on a "; format(christmas,"dddd")
print "New Year's Day 2022 is on a "; format(newyears, "dddd")
Output:

Christmas Day 2021 is on a Saturday New Year's Day 2022 is on a Saturday

jq[edit]

Works with: jq

Works with gojq, the Go implementation of jq

Years, output format, and output are exactly as for Wren.

def weekdaynames:
["Sunday", "Monday","Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
 
# example: weekday(1999; 12; 25)
def weekday($year; $month; $day):
"\($year)-\($month)-\($day)" | strptime("%Y-%m-%d") | weekdaynames[.[-2]];
 
1578, 1590, 1642, 1957, 2020, 2021, 2022, 2242, 2245, 2393
| "In \(.), New year's day is on a \(weekday(.;1;1)), and Christmas day on \(weekday(.;12;25))."
Output:

As for #Wren


Julia[edit]

See also https://docs.julialang.org/en/v1/stdlib/Dates/#Dates.format-Tuple{TimeType,%20AbstractString}

using Dates
 
for year in [1578, 1590, 1642, 1957, 2020, 2021, 2022, 2242, 2245, 2393]
println("Year $year, New Years's Day: ", Dates.format(DateTime(year, 1, 1), "E, U d, Y"),
" and Christmas: ", Dates.format(DateTime(year, 12, 25), "E, U d, Y"))
end
 
Output:
Year 1578, New Years's Day: Sunday, January 1, 1578 and Christmas: Monday, December 25, 1578
Year 1590, New Years's Day: Monday, January 1, 1590 and Christmas: Tuesday, December 25, 1590
Year 1642, New Years's Day: Wednesday, January 1, 1642 and Christmas: Thursday, December 25, 1642
Year 1957, New Years's Day: Tuesday, January 1, 1957 and Christmas: Wednesday, December 25, 1957
Year 2020, New Years's Day: Wednesday, January 1, 2020 and Christmas: Friday, December 25, 2020
Year 2021, New Years's Day: Friday, January 1, 2021 and Christmas: Saturday, December 25, 2021
Year 2022, New Years's Day: Saturday, January 1, 2022 and Christmas: Sunday, December 25, 2022
Year 2242, New Years's Day: Saturday, January 1, 2242 and Christmas: Sunday, December 25, 2242
Year 2245, New Years's Day: Wednesday, January 1, 2245 and Christmas: Thursday, December 25, 2245
Year 2393, New Years's Day: Friday, January 1, 2393 and Christmas: Saturday, December 25, 2393

ooRexx[edit]

/* REXX */
Call wkd 2021,12,25
Call wkd 2022,01,01
Exit
wkd:
Parse Arg y,m,d
wd=.Array~of('Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sunday')
dt=.DateTime~new(y,m,d)
say d'.'m'.'y 'is a' wd[dt~weekday]
Return
Output:
25.12.2021 is a Saturday
01.01.2022 is a Saturday<

Perl[edit]

#!/usr/bin/perl
 
use strict; # https://rosettacode.org/wiki/What_weekdays_will_Christmas_and_New_Year
use warnings;
use Time::Local;
 
for (
['Christmas 2021', 25, 11, 2021 ],
['New Years 2022', 1, 0, 2022 ],
)
{
print "$_->[0] ", qw( Sunday Monday Tuesday Wednesday Thursday Fridat Saturday )
[(localtime timelocal(0, 0, 12, @{$_}[1..3]))[6]], "\n";
}
Output:
Christmas 2021 Saturday
New Years 2022 Saturday

Phix[edit]

with javascript_semantics
include timedate.e
procedure nyc(integer year)
    string ny = format_timedate({year,1,1,0,0,0},"Dddd"),
           cd = format_timedate({year,12,25,0,0,0},"Dddd")
    printf(1,"In %d, New year's day is on a %s, and Christmas day on a %s.\n",{year,ny,cd})
end procedure
papply({1578, 1590, 1642, 1957, 2020, 2021, 2022, 2242, 2245, 2393},nyc)

Note the builtin timedate type does not officially support dates prior to 1752... the fact that the first three lines agree with other entries on this page is pure luck.

Output:
In 1578, New year's day is on a Sunday, and Christmas day on a Monday.
In 1590, New year's day is on a Monday, and Christmas day on a Tuesday.
In 1642, New year's day is on a Wednesday, and Christmas day on a Thursday.
In 1957, New year's day is on a Tuesday, and Christmas day on a Wednesday.
In 2020, New year's day is on a Wednesday, and Christmas day on a Friday.
In 2021, New year's day is on a Friday, and Christmas day on a Saturday.
In 2022, New year's day is on a Saturday, and Christmas day on a Sunday.
In 2242, New year's day is on a Saturday, and Christmas day on a Sunday.
In 2245, New year's day is on a Wednesday, and Christmas day on a Thursday.
In 2393, New year's day is on a Friday, and Christmas day on a Saturday.

PL/I[edit]

xmas_and_newyear: procedure options(main);
day_name: procedure(year,month,day) returns(char(9) varying);
declare days(0:6) char(9) varying;
declare (year, month, day) fixed;
declare (y, m, d, j, k) fixed;
days(0) = 'Saturday';
days(1) = 'Sunday';
days(2) = 'Monday';
days(3) = 'Tuesday';
days(4) = 'Wednesday';
days(5) = 'Thursday';
days(6) = 'Friday';
 
m = month;
y = year;
if m <= 2 then do;
m = m + 12;
y = y -1;
end;
j = y/100;
k = mod(y,100);
d = mod((day + ((m+1)*26)/10 + k + k/4 + j/4 + 5*j),7);
return(days(d));
end day_name;
 
declare years(2) fixed static initial(2021, 2022);
declare months(2) fixed static initial( 12, 1);
declare days(2) fixed static initial( 25, 1);
declare i fixed;
do i=1 to 2;
put skip edit(months(i),'/',days(i),'/',years(i),
' is a ',
day_name(years(i),months(i),days(i)))
(F(2),A,F(2),A,F(4),A,A);
end;
end xmas_and_newyear;
Output:
12/25/2021 is a Saturday
 1/ 1/2022 is a Saturday

PL/M[edit]

100H:
BDOS: PROCEDURE(F,A); DECLARE F BYTE, A ADDRESS; GO TO 5; END BDOS;
EXIT: PROCEDURE; GO TO 0; END EXIT;
PR$CH: PROCEDURE(C); DECLARE C BYTE; CALL BDOS(2,C); END PR$CH;
PR$STR: PROCEDURE(S); DECLARE S ADDRESS; CALL BDOS(9,S); END PR$STR;
 
PR$NUM: PROCEDURE(N);
DECLARE S(6) BYTE INITIAL ('.....$');
DECLARE (N, P) ADDRESS, D BASED P BYTE;
P = .S(5);
DIGIT:
P = P-1;
D = '0' + N MOD 10;
IF (N := N/10) > 0 THEN GO TO DIGIT;
CALL PR$STR(P);
END PR$NUM;
 
DAY$NAME: PROCEDURE(Y,M,D) ADDRESS;
DECLARE (Y,M,D,J,K) ADDRESS;
IF M <= 2 THEN DO;
M = M + 12;
Y = Y - 1;
END;
J = Y / 100;
K = Y MOD 100;
D = (D + ((M+1)*26)/10 + K + SHR(K,2) + SHR(J,2) + 5*6) MOD 7;
DO CASE D;
RETURN .'SATURDAY$';
RETURN .'SUNDAY$';
RETURN .'MONDAY$';
RETURN .'TUESDAY$';
RETURN .'WEDNESDAY$';
RETURN .'THURSDAY$';
RETURN .'FRIDAY$';
END;
END DAY$NAME;
 
PR$DATE: PROCEDURE(Y,M,D);
DECLARE Y ADDRESS, (M, D) BYTE;
CALL PR$NUM(M);
CALL PR$CH('/');
CALL PR$NUM(D);
CALL PR$CH('/');
CALL PR$NUM(Y);
END PR$DATE;
 
DECLARE YEARS(2) ADDRESS INITIAL (2021, 2022);
DECLARE MONTHS(2) BYTE INITIAL ( 12, 1);
DECLARE DAYS(2) BYTE INITIAL ( 25, 1);
DECLARE I BYTE;
 
DO I=0 TO 1;
CALL PR$DATE(YEARS(I),MONTHS(I),DAYS(I));
CALL PR$STR(.' IS A $');
CALL PR$STR(DAY$NAME(YEARS(I),MONTHS(I),DAYS(I)));
CALL PR$STR(.(13,10,'$'));
END;
CALL EXIT;
EOF
Output:
12/25/2021 IS A SATURDAY
1/1/2022 IS A SATURDAY

Python[edit]

 
import datetime
 
weekDays = ("Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday")
thisXMas = datetime.date(2021,12,25)
thisXMasDay = thisXMas.weekday()
thisXMasDayAsString = weekDays[thisXMasDay]
print("This year's Christmas is on a {}".format(thisXMasDayAsString))
 
nextNewYear = datetime.date(2022,1,1)
nextNewYearDay = nextNewYear.weekday()
nextNewYearDayAsString = weekDays[nextNewYearDay]
print("Next new year is on a {}".format(nextNewYearDayAsString))
 
Output:
This year's Christmas is on a Saturday
Next new year is on a Saturday

Raku[edit]

my @d-o-w = < Sunday Monday Tuesday Wednesday Thursday Friday Saturday >;
 
.say for (flat 2020..2022, (1500 .. 2500).roll(7)).sort.map: {
"In {$_}, New Years is on a { @d-o-w[Date.new($_, 1, 1).day-of-week % 7] }, " ~
"and Christmas on a { @d-o-w[Date.new($_, 12, 25).day-of-week % 7] }."
}
Sample output:
In 1578, New Years is on a Sunday, and Christmas on a Monday.
In 1590, New Years is on a Monday, and Christmas on a Tuesday.
In 1642, New Years is on a Wednesday, and Christmas on a Thursday.
In 1957, New Years is on a Tuesday, and Christmas on a Wednesday.
In 2020, New Years is on a Wednesday, and Christmas on a Friday.
In 2021, New Years is on a Friday, and Christmas on a Saturday.
In 2022, New Years is on a Saturday, and Christmas on a Sunday.
In 2242, New Years is on a Saturday, and Christmas on a Sunday.
In 2245, New Years is on a Wednesday, and Christmas on a Thursday.
In 2393, New Years is on a Friday, and Christmas on a Saturday.

Ring[edit]

? "working..."
weekdays = ["Mon","Tues","Wednes","Thurs","Fri","Satur","Sun"]
dow = timelist()[15]
today = date()
tycd = "25/12/" + substr(today, 7, 4)
nnyd = "01/01/" + string(number(substr(today, 7, 4)) + 1)
for day = 0 to 366
anotherday = adddays(today, day)
if anotherday = tycd
 ? "This year's Christmas day is on a " + nameof(day) + "."
ok
if anotherday = nnyd
 ? "The next New Year's day is on a " + nameof(day) + "."
exit
ok
next
put "done..."
 
func nameof day
return weekdays[((day + today - 1) % 7) + 1] + "day"
Output:
working...
This year's Christmas day is on a Saturday.
The next New Year's day is on a Saturday.
done...

Ruby[edit]

This uses the same years as the Raku example. The Ruby Date class does however take the calendar reform (default 1582) into account, so the days for 1578 differ from all other languages so far.

require 'date'
 
years = [1578, 1590, 1642, 1957, 2020, 2021, 2022, 2242, 2245, 2393]
years.each do |year|
xmas = Date.new(year,12,25).strftime("%A")
ny = Date.new(year, 1, 1).strftime("%A")
puts "In #{year}, New year's day is on a #{ny}, and Christmas day on #{xmas}."
end
 
Output:
In 1578, New year's day is on a Wednesday, and Christmas day on Thursday.
In 1590, New year's day is on a Monday, and Christmas day on Tuesday.
In 1642, New year's day is on a Wednesday, and Christmas day on Thursday.
In 1957, New year's day is on a Tuesday, and Christmas day on Wednesday.
In 2020, New year's day is on a Wednesday, and Christmas day on Friday.
In 2021, New year's day is on a Friday, and Christmas day on Saturday.
In 2022, New year's day is on a Saturday, and Christmas day on Sunday.
In 2242, New year's day is on a Saturday, and Christmas day on Sunday.
In 2245, New year's day is on a Wednesday, and Christmas day on Thursday.
In 2393, New year's day is on a Friday, and Christmas day on Saturday.

Wren[edit]

Library: Wren-date

This uses the same years as the Raku example.

The actual days for 1578 may have been different as the Gregorian calendar didn't start until 1582.

import "./date" for Date
 
var years = [1578, 1590, 1642, 1957, 2020, 2021, 2022, 2242, 2245, 2393]
for (year in years) {
var newYear = Date.new(year, 1, 1).weekDay
var xmas = Date.new(year, 12, 25).weekDay
System.print("In %(year), New year's day is on a %(newYear), and Christmas day on %(xmas).")
}
Output:
In 1578, New year's day is on a Sunday, and Christmas day on Monday.
In 1590, New year's day is on a Monday, and Christmas day on Tuesday.
In 1642, New year's day is on a Wednesday, and Christmas day on Thursday.
In 1957, New year's day is on a Tuesday, and Christmas day on Wednesday.
In 2020, New year's day is on a Wednesday, and Christmas day on Friday.
In 2021, New year's day is on a Friday, and Christmas day on Saturday.
In 2022, New year's day is on a Saturday, and Christmas day on Sunday.
In 2242, New year's day is on a Saturday, and Christmas day on Sunday.
In 2245, New year's day is on a Wednesday, and Christmas day on Thursday.
In 2393, New year's day is on a Friday, and Christmas day on Saturday.

XPL0[edit]

func    WeekDay(Year, Month, Day);      \Return address of day of week
int Year, Month, Day; \Works for years 1583 onward
int DayOfWeek, Names;
[if Month<=2 then [Month:= Month+12; Year:= Year-1];
DayOfWeek:= rem((Day-1 + (Month+1)*26/10 + Year + Year/4 + Year/100*6 + Year/400)/7);
Names:= ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
return Names(DayOfWeek);
]; \WeekDay
 
[Text(0, "This Christmas is on a ");
Text(0, WeekDay(2021, 12, 25)); CrLf(0);
Text(0, "This New Year's Day is on a ");
Text(0, WeekDay(2022, 1, 1)); CrLf(0);
]
Output:
This Christmas is on a Saturday
This New Year's Day is on a Saturday