要求：

用C#写一个程序，实现下图功能

实现：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _03_里氏转换练习
{
    class Program
    {
        static void Main(string[] args)
        {
            //创建一个对象 通过一个循环 去调用他们各自打招呼的方法
            //对于一个父类对象，既可以赋值父类实例，也可以赋值子类实例
            //体现里氏转换第一条 子类可以赋值给父类
            Person[] pers = new Person[10];
            Random r = new Random();
            //通过产生的随机数，来给数组进行赋值
            for (int i = 0; i < pers.Length; i++)
            {
                int rNumber = r.Next(1,7);
                switch (rNumber)
                {
                    case 1: 
                        pers[i]=new Student();
                        //体现里氏转换第二条 如果父类中装的是子类对象，那么可以将父类强制转换为子类
                        ((Student)pers[i]).StudentSayHi();
                        break;
                    case 2:
                        pers[i]=new Teacher();
                        ((Teacher)pers[i]).TeacherSayHi();
                        break;
                    case 3:
                        pers[i]=new ShuaiGuo();
                        ((ShuaiGuo)pers[i]).ShuaiGuoSayHi();
                        break;
                    case 4:
                        pers[i]=new MeiNv();
                        ((MeiNv)pers[i]).MeinvSayHi();
                        break;
                    case 5:
                        pers[i]=new YeShou();         
                        ((YeShou)pers[i]).YeShouSayHi();
                        break;
                    case 6:
                        pers[i]=new Person();
                        pers[i].PersonSayHi();
                        break;
                }
            }            
            Console.ReadKey();
        }
    }

    public class Person
    {
        public void PersonSayHi()
        {
            Console.WriteLine("我是人类");
        }
    }
    public class Student : Person
    {
        public void StudentSayHi()
        {
            Console.WriteLine("我是学生");
        }
    }
    public class Teacher : Person
    {
        public void TeacherSayHi()
        {
            Console.WriteLine("我是老师");
        }
    }
    public class MeiNv : Person
    {
        public void MeinvSayHi()
        {
            Console.WriteLine("我是美女");
        }
    }
    public class ShuaiGuo : Person
    {
        public void ShuaiGuoSayHi()
        {
            Console.WriteLine("我是帅锅");
        }
    }
    public class YeShou : Person
    {
        public void YeShouSayHi()
        {
            Console.WriteLine("我是野兽");
        }
    }
}