use strict;
use warnings;
use DateTime;

my $t1 = DateTime->new(year => 2001,
                        month => 4,
                        day => 23,
                        hour => 22,
                        minute => 32);
my $t2 = DateTime->new(year => 2001,
                        month => 4,
                        day => 22,
                        hour => 15,
                        minute => 42);
print "T1 = ".$t1->hour.":".$t1->minute."\n
       T2 = ".$t2->hour.":".$t2->minute."\n
       T1-T2 = ".$t1->subtract_datetime($t2)->hours."\n
       T2-T1 = ".$t2->subtract_datetime($t1)->hours."\n";