Why is the answer 1010?

Question

#include <iostream>
using namespace std;

int main() {
int i,j;
j=10;
i=(j++,j+100,999+j);
cout<<i;
return 0;
}

Answer 1

If you put several expressions into parentheses like this, only the last one will be stored in the variable.

So i will be 999+j.

j+100 is just a value and has no effect.

j++ on the other hand has an effect - it changes the variable j to 11.

11 + 999 is 1010.

I wonder if this would be the case in every situation - it looks like undefined behavior to me.

But to be sure, let me call in ~ swim ~. 🙂

Answer 2

Do you have any question about this?