Perl subtract two dates - perl

Question

I am fairly new in Perl.
I am trying to subtract two dates in this format
15.07.16 23:13:34
15.07.16 20:04:24
I know that I have to convert this string in a date object. My problem is I am restricted to the basic perl without installing extra packages. Is there a way to do it?
My Version is v5.8.4 and the output should be 03:09:10.

Answer 1

You say that you're using Perl 5.8.4. You really need to get that updated and get the ability to install CPAN modules.
But, here's a way to do what you want using only core Perl functionality that was available in 5.8.4.
#!/usr/bin/perl
use strict;
use warnings;
use Time::Local;
my $date1 = '15.07.16 23:13:34';
my $date2 = '15.07.16 20:04:24';
my $diff = date2sec($date1) - date2sec($date2);
print secs2duration($diff);
sub date2sec {
my ($date) = #_;
my ($day, $mon, $yr, $hr, $min, $sec) = split(/[. :]/, $date);
# I've assumed that your timestamps are in your local timezone,
# so I've used timelocal() here. If your timestamps are actually
# UTC, you should use timegm() instead.
return timelocal($sec, $min, $hr, $day, $mon-1, 2000 + $yr);
}
sub secs2duration {
my ($secs) = #_;
my $hours = int($secs / (60*60));
$secs %= (60*60);
my $mins = int($secs / 60);
$secs %= 60;
return sprintf '%02d:%02d:%02d', $hours, $mins, $secs;
}