P352作业10-P360复习

P352-P354 ==和equals区别

package com.work;
​
public class Homework03 {
    public static void main(String[] args) {
        Doctor do1 = new Doctor("L",99,"娅",'女',888.0);
        Doctor do2 = new Doctor("L",99,"娅",'女',888.0);
        System.out.println(do1.equals(do2));
    }
}
class Doctor{
    private String name;
    private int age;
    private String job;
    private char gender;
    private double sal;
​
    public Doctor(String name, int age, String job, char gender, double sal) {
        this.name = name;
        this.age = age;
        this.job = job;
        this.gender = gender;
        this.sal = sal;
    }
    public boolean equals(Object obj){
       if(this == obj){//两个是否为一个对象
           return true;
       }
       if(!(obj instanceof Doctor) ) {//不是这个类
           return false;
        }
        //向下转型，因为obj的运行是Doctor 或者子类
       Doctor doo = (Doctor) obj;
       return this.name.equals(doo.name) && this.age==doo.age &&
                this.gender==doo.gender && this.job.equals(doo.job) && this.sal ==doo.sal;
​
​
    }
//getset方法省略
​
}

P352作业11

-

Person p = new Student;//向上转型，p调用方法从子类开始找,父类的引用指向子类对象
Student s= (Person) p;//向下转型
p可以调用run,输出student run ,调用eat,person eat(找运行，运行无找父类)
s可以调用run,输出student run,调用eat,person eat,调用study ,输出...

P354 ==和equals区别面试会考

-

P355作业13内容多

package com.work;
​
public class Homework03 {
    public static void main(String[] args) {
            //多态数组
            Person [] parr=new Person[4];
            parr[0]=new Student("s1",'女',1,001);
            parr[1]=new Student("s2",'女',2,002);
            parr[2]=new Teacher("t1",'女',33,10);
            parr[3]=new Teacher("t2",'女',44,20);
​
​
    }
    public void bubble(Person [] parr) {
        Person temp=null;
        for(int i=0;i< parr.length-1;i++){
            for(int j=0;j< parr.length-1-i;j++) {
                if(parr[j].getAge()  
​
 
P357
 
 
 
A类（注意隐藏的无参构造器）
 
 
haha b类有参数构造器
 
 
c类有参构造器
 
 
c类无参构造器哦
 
 
 
 
-
 
 
 
 
P358多态的总结
 
 
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