How can you calculate the average and median in perl by subroutine?

<pre>

sub average {

@_ 1 or die ('Sub usage: $median = median(\@array);');

my ($array_ref) = @_;

my $count = scalar @$array_ref;

# Sort a COPY of the array, leaving the original untouched

my @array = sort { $a <=> $b } @$array_ref;

if ($count % 2) {

return $array[int($count/2)];

} else {

return ($array[$count/2] + $array[$count/2 - 1]) / 2;

}

}

</pre>