题解 | #重写父类方法#

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextInt()) {
            int x = scanner.nextInt();
            int y = scanner.nextInt();
            Sub sub = new Sub(x, y);//这里创建对象后，会自动调用有参构造方法，将x,y的值给基类Base;即super.x=x;super.y=y;
            System.out.println(sub.sum());
        }
    }

}

class Base {

    private int x;
    private int y;

    public Base(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public int getX() {
        return x;
    }

    public final int getY() {
        return y;
    }
//被final修饰的方法，不可以在子类重写
    public final int sum() {
        return getX() + getY();
    }

}

class Sub extends Base {

    public Sub(int x, int y) {
        super(x, y);
    }

    //重写sum()
    @Override
    public   int getX(){
        return 10*super.getX();//如果没有用this就是默认是this，super就是基类的
    }

}