C#扩充类

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace 课本习题{    public class Animal    {        public Animal()        {            Console.WriteLine("基类构造函数：Hello，Animal");        }        public void Eat()        {            Console .WriteLine("扩充类方法：Eating");        }    }    public class Cat:Animal    {        public Cat()        {            Console.WriteLine("扩充类构造函数：Hello，Cat");        }        public void Walk()        {            Console .WriteLine("扩充类方法：Walking");        }    }    class Program    {        static void Main(string[] args)        {            Cat cat=new Cat ();            cat.Eat();            cat.Walk();            Console .ReadLine();        }    }}