Then it throws 'uninitialized value in $offset' errors

I don't believe you when you say that snippet produced that warning.

Then it throws 'uninitialized value in $offset' errors which I'm guessing means the algorithm didn't find the one 'c' that had to be there.

No. If it doesn't find any 'c', it never uses $offset.

PS - Don't count out half the warning (not even counting the line number).