Small examples of Polymorphism

Polymorphism. There is no proper example. Come up with such a way to understand polymorphism. If you can figure out the output content, you can understand the polymorphism ......; If you do not understand polymorphism, I believe you will remember this example for a lifetime. [Csharp] using System; using System. collections. generic; using System. text; namespace ConsoleApplication2 {class Program {static void Main (string [] args) {Bird b1 = new public sparrow (); b1.Fly ();}} class Bird {public virtual void Fly () {Console. writeLine ("Flying... ") ;}} class Sparrow: Bird {public override void Fly () {Console. writeLine ("");} class public Sparrow: sparrow {public virtual void Fly () {Console. wri TeLine ("standing up for JJ flying... ") ;}} Output content: