问题 A: 继承 I

题目描述

编写Student类（继承Person类），
包含构造方法：
public Student()
public Student (String dep, String name,int age)
包含成员变量：
private String department;


Main类及Person类已经编写好。

import java.util.*;
public class Main
{
  public static void main(String[] args)
  {
   
    Scanner r = new Scanner(System.in);
    String dep;
    String name;
    int age;
    dep = r.next(); 
    name = r.next();
    if( !r.hasNextInt() )  
          return;
    age = r.nextInt(); 
    if( age < 0 )  
         return;
    Person stu1=new Student(dep,name,age);
    Person stu2=new Student();
    stu1.show();
    stu2.show();
  }
}

class Person
{
  protected  String name; 
  private int age; 
  public Person()
  {
  	this("anonymous",0);
        System.out.println("called the non-argument constructor of Person class");
  }
  public Person(String name, int age)
  {
    System.out