阅读源代码，写程序运行结果：public interface Shape { public double area();}public class Rectangle implements Shape{ private double width; private double height; public Rectangle(double w, double h) { width = w; height = h;} public Rectangle(double w) { width = w; height = w;} public Rectangle() { width = 1; height = 1; } @Override public double area() { return width*height; }}public class Circle implements Shape { private double radius; private static final double PI = 3.14; public Circle(double r) { radius = r;} public Circle() { radius = 1; } @Override public double area() { return radius*radius*PI; }} public class ShapeTest{ public static void main(String[] args) { Shape[] shapes = new Shape[5]; shapes[0] = new Rectangle(1,2); shapes[1] = new Rectangle(3); shapes[2] = new Rectangle(); shapes[3] = new Circle(2); shapes[4] = new Circle(); for(int i=0;i