Does the output depend on the compiler?

Question

I have a code. The code prints 1236 (g++ 7.5.0)

Does the output depend on the compiler? (eg output can be 3216 )

#include <bits/stdc++.h>


using namespace std;


int foo(int& x) {
    std::cout << ++x; 
    return x;
}


int main() {
    int i = 0;
    cout << foo(i) + foo(i) + foo(i) << endl; // 1236
}

Answer 1

No, the output does not depend on the compiler (modulo the bits/stdc++.h nonsense). The order in which the three calls foo(i) are evaluated is unspecified, but that doesn't affect the output: function calls are not interleaved, so some call will increment i to 1, print that, and return it (as a copy ), then one of the other two will assign, print, and return 2, then the last will do 3, and their return values will always sum to 6.