类的继承与多态

秒速五厘米 2022-02-13 15:29 203阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NvbWVfX29uXw_size_16_color_FFFFFF_t_70][]

其中：  
Person类具有String属性name（姓名）和display()方法；  
Teacher类继承Person类，并具有String属性professionalTitle（职称）和display()方法；  
Student类继承Person类，并具有int属性studentNumber（学号）和display()方法；  
Graduate类和Undergraduate类都继承Student类，并具有各自的display()方法,  
Graduate类具有String属性major（专业），  
Undergraduate类具有int属性grade(年级)。  
所有类都应该具有合适的构造方法和按照一定格式（见输出样例）输出所有属性值display()方法。

【输入形式】  
【输出形式】  
【样例输入】  
【样例输出】

Name: Tom  
>>>  
Name: Kevin  
Professional Title: professor  
>>>  
Name: Jerry  
StudeneNumber: 21  
>>>  
Name: John  
StudeneNumber: 22  
Grade: 3  
>>>  
Name: Mary  
StudeneNumber: 23  
Major: computer  
>>>

package day4231;
    
    public class Graduate extends Student{
    	private String major;
    	public Graduate(String name, int studentNumber,String major) {
    		super(name, studentNumber);
    		this.major=major;
    		
    	}
    	public void display(){
    		super.display();System.out.println("Major: "+major);
    	}
    
    }
    
    
    
    
    
    
    
    package day4231;
    
    public class Undergraduate extends Student{
    	private int grade;
    
    	public Undergraduate(String name, int studentNumber,int grade) {
    		super(name, studentNumber);
    		this.grade=grade;
    	}
    	public void display(){
    		super.display();
    		System.out.println("Grade: "+grade);
    	}
    
    }
    
    
    
    
    
    
    
    package day4231;
    
    public class Student extends Person{
    	private int studentNumber;
    	public Student(String name,int studentNumber) {
    		super(name);
    		this.studentNumber=studentNumber;
    	}
    	public void display(){
    		super.display();
    		System.out.println("StudeneNumber: "+studentNumber);
    		
    	}
    
    }
    
    
    
    
    
    
    
    
    package day4231;
    
    public class Teacher extends Person{
    
    	private String professionTitle;
    	public Teacher(String name,String professionTitle) {
    		super(name);
    		this.professionTitle=professionTitle;
    		
    	}
    	public void display(){
    		super.display();
    		System.out.println("Professional Title: "+professionTitle);
    		
    	}
     
    }
    
    
    
    
    
    
    
    
    
    package day4231;
    
    public class Person {
    	private String name;
    	
    	public Person(String name) {
    		super();
    		this.name = name;
    	}
    
    	public void display(){
    		System.out.println("Name: "+name);
    	}
    
    }
    
    
    
    
    
    
    package day4231;
    
    public class Test 
    {
        public static void main(String[] args) 
        {
            Person[] people = new Person[5];
            people[0] = new Person("Tom");
            people[1] = new Teacher("Kevin","professor");
            people[2] = new Student("Jerry",21);
            people[3] = new Undergraduate("John",22,3);
            people[4] = new Graduate("Mary",23,"computer");
    
            for (Person p: people)
            {
                p.display();
                System.out.println(">>>");
            }
        }
    }

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