For starters, here is a destructive solution for the differences: 

use strict;
use warnings;
 
my @array=qw/a b c d/; 

while( my $first = shift @array ) {
    print "$first-$_\n" for @array;
}

[download]

In reply to Re: How can one find out the pairwise difference and product between elements in a perl array without using a perl module? by hdb
in thread How can one find out the pairwise difference and product between elements in a perl array without using a perl module? by supriyoch_2008

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