#!/usr/bin/perl
# 計算兩日期間之距。 Compute a certain date difference.
# Copyright       : https://www.fsf.org/copyleft/gpl.HTML
# Author          : Dan Jacobson -- https://www.jidanni.org/
# Created On      : Sun Jun 16 21:48:43 2019
# Last Modified On: Sun Jun 16 22:04:30 2019
# Update Count    : 22
# Usage: $0 old new #in yyyy/mm/dd format
use strict;
use warnings FATAL => q(all);
use Time::Piece;
use Time::Seconds;
my @t;
##my $d = st('2019/06/09') - st('1999/06/19');
my $d = st(pop) - st(pop);
for (qw/years months days/) {
    push @t, sprintf "%.2f %s", $d->$_, $_;
}
print join " = ", @t;
sub st { return Time::Piece->strptime( pop, '%Y/%m/%d' ); }