in reply to Determining the dayname for the last day of any given month
Another solution without using any module:
s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e
The formular used here works like this:#!/usr/bin/perl -w use strict; while (1) { print "Enter year (yyyy) and month (mm), separated by a space:"; chomp(my $input = <STDIN>); last if !$input; my ($year, $month) = split / /, $input; my $m= $month % 12 + 1; my $y= $year+int($month/12); if ( $m<3) { $m+=12; --$y; } ++$m; my $dayname = (qw(Sat Sun Mon Tue Wed Thu Fri))[(int($m * 30.6) + +int($y * 365.25)-int($y / 100)+int($y / 400)) % 7]; print "The last day of $month/$year will be a $dayname\n"; }
- if the month is January or february (1 or 2) shift it to the end of the preceeding year (month 13 and 14)
- add 1 to the month
- sum up the integer result of:
- month * 30.6
30.6 gives it the correct toggle between 30 and 31. February is the last month, so no problem with 28/29 - year * 365.25
this takes into account the leap years - year / -100
this subtracts the non-leap years - year / 400
this re-adds the non-non-leap years
- month * 30.6
- the day should then be added
s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e
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