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();   }
}