《Monkey Java》课程5.3之子类实例化

class Person{
  String name;
  int age;
  Person(){
    System.out.println("Person的无参数构造函数");
  }
  Person(String name, int age){
    this.name = name;
    this.age = age;
    System.out.println("Person的有参数构造函数");
  }
  void eat(){
    System.out.println("吃东西");
  }
  void introduce(){
    System.out.println("我的名字叫 " + this.name + "，我的年龄 " + this.age);
  }
}

class Student extends Person{
  int grade;
  Student(){
    System.out.println("Student的无参数构造函数");
  }

  Student(String name, int age, int grade){
    // 调用父类Person当中的有两个参数name和age的构造函数
    super(name, age);
    this.grade = grade;
    System.out.println("Student的有参数构造函数");
  }

  void study(){
    System.out.println("我学习的年级是 " + this.grade);
  }
}

class Demo01{
  public static void main(String[] args) {
    Student stu01 = new Student("zhang3",18,3);
    stu01.eat();
    stu01.introduce();
    stu01.study();
  }
}