package Homework;

public abstract class shape {
    public abstract void draw();
}
class Circle extends shape{
    @Override
    public void draw(){
        System.out.println("绘制一个圆形");
    }

}
class Rectangle extends shape{
    @Override
    public void draw(){
        System.out.println("绘制一个矩形");
    }
}
class Main{
    public static void drawShape(shape s){
        s.draw();
    }
    public static void main(String[]args){
        drawShape(new Circle());
        drawShape(new Rectangle());
    }
}