第10章 接口、继承与多态 多态

package ten;
public class Quadrangle {
    private Quadrangle[] qtest=new Quadrangle[6];
    private int nextIndex=0;
    public void draw(Quadrangle q){
        if(nextIndex<qtest.length){
            qtest[nextIndex]=q;
            System.out.println(nextIndex);
            nextIndex++;
        }
    }
    public static void main(String args[]){
        Quadrangle q=new Quadrangle();
        q.draw(new Square());//以正方形对象为参数调用draw()方法
        q.draw(new Parallelogramgle());
    }
}
class Square extends Quadrangle{
    public Square(){
        System.out.println("正方形");
    }
}
class Parallelogramgle extends Quadrangle{
    public Parallelogramgle(){
        System.out.println("平行四边形");
    }
}