note
ichimunki
<strike>Are you sure that %alphabet contains data? None of the code above shows us how data gets in there... and if data gets in there for likely values of $s.</strike>
<p>
Is it issuing this warning multiple times for the same run? Otherwise: you get an error the first time through because you never set $alphabet{$s} to anything for its first use, but at the end of your sub, you ++ it, which means that thereafter it has a valid value (i.e. has been "initialized").
191175
191175