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

my @randomarray = ( 0 .. 100 );

my $sub1 = sub {
        for(my $j, my $x, my $i = scalar @randomarray; $i;$j = int(rand($i)), $x = $randomarray[--$i], $randomarray[$i] = $randomarray[$j], $randomarray[$j]
= $x){
        }
};

my $sub2 = sub {
        my $i = scalar @randomarray;
        while ($i){
                my $j = int(rand($i));
                my $x = $randomarray[--$i]; #next value
                $randomarray[$i] = $randomarray[$j]; #next value = random value
                $randomarray[$j] = $x; #current random value = next value.
        }
};

use Benchmark;

timethese(100000, {
                'Sub 1' => $sub1,
                'Sub 2' => $sub2,
        });

##</code><code>##

Benchmark: timing 100000 iterations of Sub 1, Sub 2...
     Sub 1: 28 wallclock secs (27.37 usr +  0.00 sys = 27.37 CPU) @ 3654.01/s (n=100000)
     Sub 2: 40 wallclock secs (32.25 usr +  0.00 sys = 32.25 CPU) @ 3100.78/s (n=100000)