C++, when I put return 0 in a function and use the function main, the system still keep working

Question

My idea is to write a exit function to terminate the whole system, so I wrote the function int exit_c(), and put it in the while loop, but it seems that the system keeps working.

int main() {

    while (true) {
        exit_c();
    }

    system("pause");
    return 0;
}

int exit_c() {
    cout << "close" << endl;
    system("pause");
    return 0;
}

But when I replace the exit_c() in while loop, which just system("pause") and return 0, the system will terminate.

int main() {

    while (true) {
        system("pause");
                return 0;
    }

    system("pause");
    return 0;
}

Answer 1

return returns from a function. Hence, you cannot simply copy the code in the function to replace its call and expect the code to behave the same. The return 0; which before returned from exit_c now returns from main. Thats the difference you see.

On a related note: return 0; in main is implicit. You can remove it from your code when it is the last statement.