static void Main()
{
    int i = 2, j = 3;
    System.Console.WriteLine("i = {0}  j = {1}" , i, j);

    SwapByRef (ref i, ref j);

    System.Console.WriteLine("i = {0}  j = {1}" , i, j);

    // Keep the console window open in debug mode.
    System.Console.WriteLine("Press any key to exit.");
    System.Console.ReadKey();
}
/* Output:
    i = 2  j = 3
    i = 3  j = 2
*/