继承

继承

package test4;

public class test4 {

    public static void main(String[] args) {

        /*System.out.print("Hello\n");
        Person person = new Person();
        person.age = 15;
        person.name = "秦川";
        person.speak();*/

        Student stu = new Student();
        stu.age = 20;
        stu.name = "Jack";
        stu.number = 2211;
        stu.score = 100;
        stu.speak();
        stu.printScore();
    }

}


class Person{
    int age;
    String name;
    void speak(){
        System.out.print("大家好，我是"+name+"，今年"+age+"岁了。\n");
    }
}

class Student extends Person {
    int number;
    int score;
    void printScore() {
        System.out.print("我的学号是"+number+",成绩是"+score);
    }
}

super

父类属性：super.属性

父类构造方法：super(参数)

package test4;

public class test4 {

    public static void main(String[] args) {

        /*System.out.print("Hello\n");
        Person person = new Person();
        person.age = 15;
        person.name = "秦川";
        person.speak();*/

        Student stu = new Student();
        stu.age = 20;
        stu.name = "Jack";
        stu.number = 2211;
        stu.score = 100;
        stu.speak();
        stu.printScore();
    }

}


class Person{
    Person(int age) {
        this.age = age;
    }

    int age;
    String name;
    void speak(){
        System.out.print("大家好，我是"+name+"，今年"+age+"岁了。\n");
    }
}

class Student extends Person {
    Student(){
        super(18);
    }
    int number;
    int score;
    void printScore() {
        System.out.print("，成绩是"+score);
    };
    void speak(){
        super.speak();
        System.out.print("学号："+number);
    }
}