What is the output of this program?

Question

#include <iostream>

int main() {
int a = 0;
std::cout << (++--++a)++ + ++a;
return 0;
}

Answer 1

The output should be 4...
Why? ++--++ is the same as ++ so you could rewrite your expresion as: (++a)++ + ++a... What happends then? the value in a is incremented two times before the addition leaving: (2)++ + 2 which is equal to 4... after that, a is incremented by one one more time leaving the value in a equal to 3... but as I said before, what you get on screen is 4 which is the sum of a before the last increment...

Answer 2

But in this program the order of operations are well defined...

Answer 3

Error