Why can you return a const char* in main?

Question

Can anyone explain how this code doesn't give errors when compiled?

int main()
{
  // why doesn't the following line give a type mismatch error??/
  return "success!";
}

Answer 1

Because of the trigraph ??/, which is replaced by a \, meaning the return is commented out. Your code is equivalent to

int main()
{
  // why doesn't the following line give a type mismatch error\
  return "success!";
}

which is the same as

int main()
{
  // why doesn't the following line give a type mismatch error return "success!";
}

Also note that, in the absence of a return statement in main, there is an implicit return 0;, so the code is well defined.