In most swap operations, we use a third variable. The following code snippet shows how we can use just two int variables to swap their values.
  1. using System;
  2. namespace swap
  3. {
  4. class Program
  5. {
  6. static void Main(string[] args)
  7. {
  8. int first, second;
  9. Console.WriteLine("ENTER THE FIRST NO");
  10. first = int.Parse(Console.ReadLine());
  11. Console.WriteLine("ENTER THE Second NO");
  12. second = int.Parse(Console.ReadLine());
  13. if (first != second)
  14. {
  15. first = first + second;
  16. second = first - second;
  17. first = first - second;
  18. Console.WriteLine("The First No is After Swapping {0}", first);
  19. Console.WriteLine("The Second No is After Swapping {0}", second);
  20. Console.ReadLine();
  21. }
  22. else
  23. Console.WriteLine("The First and Second No Should be Different");
  24. Console.ReadLine();
  25. }
  26. }
  27. }