In GNU C, you may use C++ style comments, which start with // and
continue until the end of the line. Many other C implementations allow
such comments, and they are likely to be in a future C standard.
However, C++ style comments are not recognized if you specify
-ansi, a -std option specifying a version of ISO C
before C99, or -traditional, since they are incompatible
with traditional constructs like dividend//*comment*/divisor.