C++ comma operators

The comma operator has left-to-right associativity. Two expressions separated by a comma are evaluated left to right. The left operand is always evaluated, and all side effects are completed before the right operand is evaluated.

• The comma operator is mainly useful for obfuscation.
• The comma operator allows grouping expression where one is expected.
• Commas can be used as separators in some contexts, such as function argument lists.

Example :

#include <iostream>
using namespace std;
int main ()
{
    int i = 10, b = 20, c= 30;

    // here, we are using comma as separator
    i = b, c;

    cout<<i<<"\n";

    // bracket makes its one expression.
    // all expression in brackets will evaluate but
    // i will be assigned with right expression (left-to-right associativity)
    i = (b, c);
    cout<<i<<"\n";

    return 0;
}

Output :

    20
    30