“C - C++” joke about postfix/prefix operation ordering

Question

My friend sent me a joke:

Q. What\'s the difference between C and C++?

A. Nothing, because: (C - C++ == 0)

I tried to change

Answer 1

Because c++ - c becomes (c - c-incremented-by-one), which is -1 and ++c - c becomes (c-incremented-by-one - c-incremented-by-one) which is 0.