package com.niuke_1; class Student { String name; int age; public Student(String name, int age){ this.name = name; this.age = age; } public void show(){ System.out.println("name: "+name+" age: "+age); } } class Undergraduate extends Student { private String degree; public Undergraduate(String name, int age, String degree){ super(name, age); this.degree = degree; } public void show(){ System.out.println("name: "+name+" age: "+age+" degree: "+degree); } } public class demo_3 { public static void main(String[] args){ Student stu = new Student("张三",20); stu.show(); Undergraduate ug = new Undergraduate("李四", 18, "本科"); ug.show(); } }