Swap Two Numbers Without using Third Variable in C#

Introduction

The given below code swaps two given values of variables without using the third variable in C#.

namespace CDEMO.

{
class Program
{
     static void Main(string[] args)
     {
           int first,second ;
           first = 1;
           second = 2;
           first = first + second;
           second = first - second;
           first = first - second;
           Console.WriteLine(first.ToString());
            Console.WriteLine(second.ToString());
            Console.ReadLine();
        }
     }
}