這段代碼編譯通過，課時結果居然顯示函數錯誤？！！

提問者：裝瘋裝傻裝純潔  |  瀏覽 次  |  提問時間：2017-02-16  |  回答數量：3

public class TestShape {static public void mian(String[] args){Shape[] s=new Shape[2];s[0]=new Rect(3,4);s[1]=new Circle(2);for(int i=0;i<s.length;i++){System.out.println(s.sqr());System.out.println(s.per());}}}class Shape{public Shape(){}public double sqr(){return 0;}public double per(){return 0;}}class Rect extends Shape{private double x;private double y;public Rect(){}public Rect(double x,double y){this.x=x;this.y=y;}public double sqr(){return x*y;}public double per(){return (x+y)*2;}}