#!/usr/bin/perl
use warnings;
use strict;

my @array = (12, 6, 2, 9, 15);

for (my $i = 0; $i < $#array; $i++) {
    for (my $j = 0; $j < $#array; $j++) {
        if ($array[$j] > $array[$j+1]) {
            my $tmp = $array[$j+1];
            $array[$j+1] = $array[$j];
            $array[$j] = $tmp;
            warn "$i $j : @array\n";
        }
    }
}

print "array : @array \n";