931012-1.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

f (int b, int c)
{
  if (b != 0 && b != 1 && c != 0)
    b = 0;
  return b;
}

main ()
{
  if (!f (1, 2))
    abort();
  exit(0);
}