static void Main(string[] args)
{
DateTime dt = DateTime.ParseExact("24/01/2013", "dd/MM/yyyy", CultureInfo.InvariantCulture);
DateTime date31 = DateTime.ParseExact("15/07/2017", "mm/dd/yyyy", CultureInfo.InvariantCulture);
ExtDemoClass ob = new ExtDemoClass();
ob.Display();
ob.Print();
ob.NewMethod();
Console.ReadKey();
}
public static void NewMethod(this ExtDemoClass ob)
{
Console.WriteLine("Hello I m extended method");
}