for ( my $i = 0; $i <= length( $v1 ); $i++ ) {
my ( $n1, $n2 ) = ( ord( substr( $v1, $i, 1 ) ),
ord( substr( $v2, $i, 1 ) ) );
for ( my $i = 0; $i <= length( $v1 ); $i++ ) {
my ( $n1, $n2 ) = ( ord( substr( $v1, $i, 1 ) ),
ord( substr( $v2, $i, 1 ) ) );