http://www.perlmonks.org?node_id=1043587


in reply to Statistic in Perl(Using Subroutines)

sub average { @_ == 1 or die ('Sub usage: $average = average(\@array);'); my ($array_ref) = @_; my $sum; my $count = scalar @$array_ref; foreach (@$array_ref) { $sum += $_; } return $sum / $count; }
sub average { ref( my $array_ref = $_[ 0 ] ) eq 'ARRAY' or die 'Sub usage: $average = average(\@array);'; my $sum; $sum += $_ for @$array_ref; return $sum / @$array_ref; }