# Faulty Algorithm: double int's in range [1..4] my %hDouble = (1=>'2', 2=>'4', 3=>'7', 4=>'8'); # Kinky Perl computation: assert (&& thus fix) algorithm for my $i (1..4) { my $o = $hDouble{$i}; $o-- if ($o%2 != 0); print $i . "=>" . $o . "\n"; }