#!/usr/bin/perl
use strict;
use warnings;
use Time::Piece;


my @date = (
    '2014-06-01',
    '2014-06-02',
    '2014-06-03',
    '2014-06-04'
);

for my $i (0 .. $#date-1) {
	my $d1 = Time::Piece->strptime($date[$i], '%Y-%m-%d');
	for my $j ($i+1 .. $#date) {
		my $d2 = Time::Piece->strptime($date[$j], '%Y-%m-%d');
		my $diff = $d2 - $d1;
		print $d1->ymd, " and ", $d2->ymd, " is ", $diff->days, "\n";
	}	
}