if (exists($hash->{$cur})) {
    $hash->{$cur}++;
}
else {
    $hash->{$cur} = 1;
}
[download]

No need to jump through hoops. Perl doesn't complain when increasing undefined variables, so this will do:

$hash->{$cur}++;
[download]

It's the accept practice for this case, in fact, so it should be done this way as well.

Makeshifts last the longest.