C#入门作业二补充

3.定义一个类Student，包含属性值:ID(学号）、Name（姓名）、Department（院系）Courses（选修课程，字符串数字）；
类graduateStudent 继承Student，具有自己的属性Research（研究方向）
类Student和类graduateStudent均包含无参构造函数和有参构造函数
代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;/*3.定义一个类Student，包含属性值:ID(学号）、Name（姓名）、Department（院系）Courses（选修课程，字符串数字）；类graduateStudent 继承Student，具有自己的属性Research（研究方向）类Student和类graduateStudent均包含无参构造函数和有参构造函数*/namespace student{    class Program    {        class Student        {            private string  ID;            private string Name;            private string  Department;            private string[] Course;            public Student ()            {                 this.ID =" 000000";                this.Name = "张三";                this.Department = "计算机";                this.Course=new string [3] { "C#","数据结构","C++"};             }            public Student(string id, string name, string department,string [] course)            {                this.ID = id;                this.Name = name;                this.Department = department;                this.Course = course;            }            public void toString ()            {                Console.WriteLine("我叫{0},我的学号是{1}，我的专业是{2}\n我选修了{3}、{4}、{5}", this.Name, this.ID, this.Department, this.Course[0], this.Course[1], this.Course[2]);            }        }        class graduteStudent:Student        {            private string Research;            public graduteStudent():base()            {                Research = "信息安全";            }            public graduteStudent(string research, string id, string name, string department, string []course):base(id,name,department,course)            {                Research = research;            }            public new void toString ()            {                base.toString();                Console.WriteLine("我研究的方向是{0}", Research);            }        }        static void Main(string[] args)        {            string [] course2 = { "英语1", "英语2", "英语3" };            Student st1 = new Student();            st1.toString();            Student st2 = new Student("111111", "李四","英语专业",course2);            st2.toString();            graduteStudent st3 = new graduteStudent();            st3.toString();            string[] course4 = { "物理", "化学", "生物" };            graduteStudent st4 = new graduteStudent("导弹研制","222222", "王五", "物理专业",course4 );            st4.toString();            Console.ReadLine();        }    }}

运行截图