public static void Main()
Console.WriteLine("1st Number =");
Console.WriteLine( FirstNumber);
Console.WriteLine( "2nd Number = ");
Console.WriteLine(SecondNumber);
Console.WriteLine("swapping start : ");
FirstNumber=SecondNumber;
Console.WriteLine("1st Number =");
Console.WriteLine(FirstNumber);
SecondNumber=FirstNumber;
Console.WriteLine( "2nd Number = ");
Console.WriteLine(SecondNumber);