use strict; use warnings; my $string = 'abcdefghi'; print 'Original string: ', $string, "\n"; print 'Using function: ', reverse_in_place($string), "\n"; print 'Using reverse: ', scalar reverse ($string), "\n"; # For comparison sub reverse_in_place { my ($string) = @_; my @array = split //, $string; my $n = scalar @array; for (0 .. $n / 2 - 1) { my $tmp = $array[$_]; $array[$_] = $array[$n - $_ - 1]; $array[$n - $_ - 1] = $tmp; } return join('', @array); }