C# 的面向对象特性之继承 还有多态

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
/// <summary>
/// C# 的继承是为实现创建一个新类，同时重用，扩展，修改已有的另一个类里的一种方式。
/// 同时它应该遵循 Is-A 原则。还重点介绍了实现继承的几个关键字。
/// override 与 new 的区别
/// </summary>
namespace lesson9
{
    class Program
    {
        static void Main(string[] args)
        {
            Dog dog = new Dog();//实例化的时候先会调用父类的构造函数
            dog.Age = 10;
            dog.Bite();
            dog.GetAge();
            dog.BiteMan();

            Animal oldDog = new Dog();//隐式的类型转换 实例化一个animal 类型的 dog对象
            oldDog.Bite();//overwrite 是重写了父类的方法
            oldDog.BiteMan();//new 出来 子类对父类影藏 父类中的biteman并没有重写
            ((Dog)oldDog).BiteMan();
            Console.ReadLine();
        }
    }

    class Animal{
     public Animal()
        {
            Console.WriteLine("Animal constructor");
        }
    public int Age
    {
        get;
        set;
    }
        public virtual void Bite()//virtual 意思在与继承中可以重写
        {
            Console.WriteLine("Animal bite");
        }

        public virtual void GetAge()
        {
            Console.WriteLine(Age);
        }

        public void BiteMan()
        {
            Console.WriteLine("Animal bite man");
        }


    }

    sealed class Dog:Animal //这里的Dog 前面加了sealed就无法被继承
    {
        public Dog()
        {
            Console.WriteLine("Dog constructor");
        }
        public override void Bite()
        {
            Console.WriteLine("Dog bite");
        }

        public new void BiteMan()//把父类的方法，在子类中影藏
        {
            Console.WriteLine("Dog bite man");
        }
    }


}

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
/// <summary>
/// 1.C#的静态多态 在编译时就已经实现了多态
///2.C#的动态多态 在运行时实现的多态
/// </summary>
namespace lesson10
{
    class Program
    {
        static void Main(string[] args)
        {
            PrintHello();
            PrintHello("world");//这里是方法的多态 重载
            Complex c1 = new Complex();
            Complex c2 = new Complex();
            c1.Number = 2;
            c2.Number = 3;
            Console.WriteLine((c1 + c2).Number);

            Human human1 = new Man();//这里实现了动态的重载
            Human human2 = new Woman();
            human1.CleanRoom();
            human2.CleanRoom();
            Console.WriteLine(c2);
            //some logic
            //Human h=new Human();
            //if(he is man)
            //h.CleanRoomSlowly();
            //else if (h is woman)
            //h.cleanroomqucik();
            //some logic


            Console.ReadLine();
        }

        public static void PrintHello()
        {
            Console.WriteLine("Hello");
        }

        public static void PrintHello(string toWho)
        {
            Console.WriteLine("Hello {0}", toWho);
        }
        //运算符的重载 对加号的重载
        class Complex
        {
            public int Number { get; set; }

            public static Complex operator +(Complex c1, Complex c2)
            {
                Complex c = new Complex();
                c.Number = c1.Number + c2.Number;
                return c;
            }
            //实现了对toString 方法的重写
            public override string ToString()
            {
                return Number.ToString();
            }
        }

        class Human{
    public virtual void CleanRoom()
        {
            Console.WriteLine("Human clean room");
        }
    }

        class Man:Human
        {
            public override void CleanRoom()
            {
                Console.WriteLine("man Clean slowly");
            }
        }

        class Woman : Human
        {
            public override void CleanRoom()
            {
                Console.WriteLine("women Clean quaikly");
            }
        }
}
    

}