How to work this program? Explain this program.

Question

#include <iostream>
using namespace std;

int main() {
int i=1,j=2,k=3;
int w;
w=(i,j,k);
cout <<w;
int r;
{r=i,j,k;}
cout<<r;
int q;
q=i,j,k;
cout<<q;
return 0;
}

Answer 1

https://en.wikipedia.org/wiki/Comma_operator

You may also take a look at C++ operator precedence.

http://en.cppreference.com/w/cpp/language/operator_precedence

As you can see, comma is at the bottom of the table (least precedence). Hence, when we do:

w=(i,j,k);

(i,j,k) is evaluated first due to the parenthesis.

As for {r=i,j,k;} and q=i,j,k;

The assignment operator = is evaluated prior to the comma operator.

Answer 2

output :311