题解 | #实现抽象方法#

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // Sub是需要你定义的子类
        Base base = new Sub();

        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextInt()) {
            int x = scanner.nextInt();
            int y = scanner.nextInt();
            base.setX(x);
            base.setY(y);
            System.out.println(base.calculate());
        }
    }

}

abstract class Base {

    private int x;
    private int y;

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public int calculate() {
        if (avg() == 0) {
            return 0;
        } else {
            return sum() / avg();
        }
    }
    public abstract int sum();

    public abstract int avg();

}

class Sub extends Base {

   public int sum(){
       return getX()+getY();
   }
   public int avg(){
       return (getX()+getY())/2;
   }


}