In C a char is an int. A char constant is really and truely an int, while a char is an 8 bit quantity that behaves like an int (and may be signed or not depending on compiler and options).

In Perl a char is a string containing a single character. Using a string in a numerical context 'numifies' the string - gets it interpreted as a number. The string constant 'c' turns into 0 when numified. Not what you want. What you need is to use the function ord which produces the ordinal value for the first character in the string passed to it.