构造函数

class Program
    {
        static void Main(string[] args)
        {
            
            Pet dog = new Dog("DD");//创建指向派生类Dog的基类Pet的实例
           
            dog.Speak();//此处是调用Pet类的虚方法Speak()，根据dog所指向的派生类Dog而调用Dog里的同名重写方法Speak()---即多态
           
           Pet cat = new Cat("CC");//创建指向派生类Cat的基类Pet的实例
           
             cat.Speak();//此处是调用Pet类的虚方法Speak()，根据cat所指向的派生类Cat而调用Cat里的同名重写方法Speak()---即多态

        }

    }
    public class Pet
    {
        protected string Name;//protected 保护级别，派生类可访问
        public Pet(string name)//基类的构造函数
        {
            Name = name;
        }
        public void PrintName()
        {
            Console.WriteLine("Print"+Name);
        }
        
        virtual public void Speak()
        {
            Console.WriteLine("I‘m "+Name);  
        }
    }
    public class Dog : Pet
    {
        public Dog(string name):base(name)//构造函数//用关键字base调用了基类的构造函数
        {
           
        }
        new public void PrintName()
        {
            Console.WriteLine("子打印"+base.Name);//此处Name是Pet.Name
        }
        override public void Speak()//重写基类Pet的虚方法
        {
            Console.WriteLine("子说" + Name);
        }
    }
    public class Cat : Pet
    {
        public Cat(string name):base(name)//构造函数//用关键字base调用了基类的构造函数
        {
            
        }
        new public void PrintName()
        {
            Console.WriteLine("子打印" + Name);//此处Name是Pet.Name
        }
        override public void Speak()//重写基类Pet的虚方法
        {
            Console.WriteLine("子说" + Name);
        }
    }