[Perl] 曜日の取得

曜日の求め方

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print getwday(2003, 8, 18);

# Zellarの公式で曜日を求める
# 0:日 ... 6:土
sub getwday {
my $year = shift; # 年
my $mon = shift; # 月
my $day = shift; # 日

if ($mon == 1 or $mon == 2) {
 $year--;
 $mon += 12;
}
my $number = ($year + int($year / 4) - int($year/100) + int($year / 400)
 + int((13 * $mon + 8) / 5) + $day) % 7;

my @list = ('sun.','mon.','the.','wed.','thu.','fri.','sat.');


 return @list[$number];
}

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