C++ Tutorial/Operators statements/Comma operator

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Comma operator

#include <iostream> 
using namespace std; 
 
int main() 
{ 
  int i, j; 
 
  j = 10; 
 
  i = (j++, j+100, 999+j); 
 
  cout << i; 
 
  return 0; 
}
1010

Demonstrating the comma operator

#include <iostream>
#include <iomanip>
using std::cout;
using std::cin;
using std::endl;
using std::setw;
int main() {
  int count = 10;
  for(long n = 1, sum = 0, factorial = 1;sum += n, factorial *= n, n <= count ;
 n++)
    cout << setw(4) << n   << "    "
         << setw(7) << sum << " "
         << setw(15) << factorial
         << endl;
  return 0;
}
1          1               1
   2          3               2
   3          6               6
   4         10              24
   5         15             120
   6         21             720
   7         28            5040
   8         36           40320
   9         45          362880
  10         55         3628800

The Comma Operator: The value of a series of expressions is the value of the right most

#include <iostream>
using namespace std;
int main()
{
   long num1 = 0, num2 = 0, num3 = 0, num4 = 0;
   num4 = (num1 = 10, num2 = 20, num3 = 30);
   cout << num4;
   cout << endl;
   return 0;
}