继承

package day01;

public class Employee {
    String name;
    int num;

    public Employee() {
        System.out.println("wuc  fu Employee");
    }
    public  Employee(String name,int num){
        System.out.println("youc  fu Employee");
        this.name=name;
        this.num=num;
    }
    public String getName() {
        return name;
    }

    public int getNum() {
        return num;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setNum(int num) {
        this.num = num;
    }

    public void m(){
        System.out.println("我想你了"+this.name);
    }
}

package day01;


public class Teacher extends Employee{//一个子类只能有一个父亲，父亲有多个儿子
    public Teacher() {
        System.out.println("wuc zi Teacher");
    }
    public  Teacher(String name,int num){
        super(name,num);//super可以调用父类有参方法
        System.out.println("youc zi Teacher");
        /*this.name=name;
        this.num=num;*/
    }
    @Override   //检测是否重写正确
    public void m(){
        System.out.println("我是老师");
        System.out.println("我想你了"+this.name);
        System.out.println("我想你了"+super.name);//super是指向父类
    }
}

package day01;

public class It extends Employee{
    public It() {
        System.out.println("wuc zi IT");
    }
    public  It(String name,int num){
        super(name,num);//super可以调用父类有参方法 这样就不用自动调用无参的了
        System.out.println("youc zi IT");
       /* this.name=name;
        this.num=num;*/
    }
    @Override   //检测是否重写正确
    public void m(){
        System.out.println("我是程序员");
        System.out.println("我想你了"+this.name);
        System.out.println("我想你了"+super.name);//super指向父类
    }
}

package day01;

public class Case13 {
    public static void main(String[] args) {
        It a=new It("Lucken",18);  //子类    //先调用父类无参构造方法，再调用子类构造方法
        Teacher b=new Teacher("luying",22);  //子类
      /*  a.name="Lucken";
        b.name="luying";
        a.num=18;
        b.num=22;*/
        a.m();  //子类特有方法 可以用父类（先用子类，子类没有用父类）
        //（子类返回值范围要小于父类，子类的权限要大于等于父类）
        b.m();  //子类特有方法  可以用父类
        Employee c=new Employee();  //父类不能用子类方法
        c.name="jae";
        c.num=21;
        c.m();
    }

}