qq_我亦久飘零_0
package com.Shape;class interface Shape{ double area (double d);}class Square implements Shape{ public double area(double d); {return d*d; }}class Circle implements Shape{ public double area(double d); { return d*d*3.14; }}public class Shape{ public static void main(String[] args) { Square square =new Square; System.out.println(Square.area(2)); }}