Java语言程序设计（选修课） .doc

类与对象的基础题：1）编程实现：设计一个学生类student，包含的属性有姓名name和年龄age. 由学生类派生出本科生类undergraduate和研究生类postgraduate, 本科生类包含的属性有专业specialty等, 研究生类包含的属性有研究方向studydirection等。每个类都有相关数据的set方法和get方法.2）声明测试类：声明student类的数组（含5个元素），生成五个对象存入数组：其中二个student类的对象、二个postgraduate类的对象、一个undergraduate类的对象，打印输出每个对象的某个成员变量。将一个父类的引用指向一个子类对象，用这个塑型后的对象来调用某个方法实现多态性。/声明学生类 studentclass studentprivate string name;/姓名private int age;/年龄/构造方法public student()public student(string name, int age) = name;this.age = age;/get方法public string getname()return ;public int getage() return this.age;/set方法public void setname(string name)=name; public void setage(int age) this.age = age;public void study() system.out.println(普通学生);/声明本科生类 undergraduateclass undergraduate extends studentpublic string specialty;/专业/构造方法public undergraduate() public undergraduate(string name, int age, string specialty)super(name, age); this.specialty = specialty; /get方法public string getspecialty() return this.specialty;/set方法public void setspecialty() this.specialty = specialty; public void study() system.out.println(本科生); /声明研究生类 postgraduateclass postgraduate extends studentpublic string studydirection;/研究方向/构造方法public postgraduate() public postgraduate(string name, int age, string studydirection) super(name, age); this.studydirection = studydirection;/get方法public string getstudydirection() return studydirection;/set方法public void setstudydirection() this.studydirection = studydirection; public void study() system.out.println(研究生);/声明测试类 testerpublic class testerpublic static void main(string args) int i; student student = new student5; student0 = new student(li mei, 15); student1 = new student(wang hai, 18); student2 = new postgraduate(wu fan, 24, 法学); student3 = new postgraduate(zhang jie, 25, 物理学); student4 = new undergraduate(huang yue, 20, 微电子学); for(i=0; istudent.length; i+) system.out.println(姓名： + studenti.getname()+ +年齡：+studenti.getage(); student stu = new postgraduat