学生系统 问题描述 设计一个学生类 Student,其属性有 name（姓名）、age（年龄）和 degree（学位）。由 Student 类派生出本科生类 Undergraduate 和研究生类 Graduate，Undergraduate 类增加属性 specialty（专业），研究生类增加属性 direction（研究方向）。每个类都有 show()方法， 用于输出属性信息。 注： （1） 所有的输入均为英文，不含中文。 （2） 编写测试类 Test 进行测试，分别声明 2 个类的对象，并调用 show()方法。 （3） 输出结果为： name:sky age:23 degree:Graduate direction:software name:sky age:23 degree:Undergraduate specialty:java 要Java代码

以下是Java代码实现：

class Student {
    String name;
    int age;
    String degree;

    public void show() {
        System.out.println("name:" + name + " age:" + age + " degree:" + degree);
    }
}

class Undergraduate extends Student {
    String specialty;

    public void show() {
        System.out.println("name:" + name + " age:" + age + " degree:" + degree + " specialty:" + specialty);
    }
}

class Graduate extends Student {
    String direction;

    public void show() {
        System.out.println("name:" + name + " age:" + age + " degree:" + degree + " direction:" + direction);
    }
}

public class Test {
    public static void main(String[] args) {
        Undergraduate u = new Undergraduate();
        u.name = "sky";
        u.age = 23;
        u.degree = "Undergraduate";
        u.specialty = "java";
        u.show();

        Graduate g = new Graduate();
        g.name = "sky";
        g.age = 23;
        g.degree = "Graduate";
        g.direction = "software";
        g.show();
    }
}

输出结果为：

name:sky age:23 degree:Undergraduate specialty:java
name:sky age:23 degree:Graduate direction:software