package Demo.oop.APP.Demo05;
public class application {
public static void main(String[] args) {
//object>String
//Object>Person>student
//Object>Person>Teacher
Object object = new Student();
Person person=new Student();
System.out.println(object instanceof Student );//true
System.out.println(object instanceof Person);//true
System.out.println(object instanceof Teacher);//false
System.out.println(object instanceof String);//false
System.out.println("=====================");
System.out.println(person instanceof Student);//ture
System.out.println(person instanceof Teacher);//false
//System.out.println(person instanceof String);//编译报错
}
}
/**
* 1.父类引用指向子类对象
* 2.把子类转为父类，向上转型
* 3.把父类转换为子类，向下转换，强制转换
* 4.方便方法调用，减少代码重复
* 抽象-->封装，继承，多态
*/
package Demo.oop.APP.Demo05;
public class Person {
}
package Demo.oop.APP.Demo05;
public class Student extends Person{
}
package Demo.oop.APP.Demo05;
public class Teacher extends Person{
}
