#!/usr/bin/perl -w
use strict;

my @array = qw/1 2 3 4 9/;

print median(@array);

sub median
{
    my @vals = sort {$a <=> $b} @_;
    my $len = @vals;
    if($len%2) #odd?
    {
        return $vals[int($len/2)];
    }
    else #even
    {
        return ($vals[int($len/2)-1] + $vals[int($len/2)])/2;
    }
}