using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplicationTest{    class Program    {        static void Main(string[] args)        {            Student s = new Student("‘zhangsan",19,1);            //父类中的person say hello 没有输出，原因是隐藏了父类的方法             //如果想有意隐藏父类的同名方法 使用关键字new            s.SayHello(); //student say hello            Console.ReadKey();        }    }    public class Person     {        public string Name { get; set; }        public int Age { get; set; }        //父类构造函数        public Person(string name,int age)        {            this.Name = name;            this.Age = age;        }        public void SayHello()        {            Console.WriteLine("person say hello");        }        }    public class Student:Person        {        public int Id { get; set; }        //子类构造函数        //关键字base的使用：调用父类的构造函数        public Student(string name,int age,int id):base(name,age)        {            this.Id = id;        }        public new void SayHello()        {            Console.WriteLine("student say hello");        }    }}