1  定义接口IShape 其中有void area（）方法，用于计算形状的面积；
2  定义类Circle和Rect，均实现IShape接口；
3  给定Circle的半径，Rect的两边长，比较二者面积的大小（使用上转型对象完成）！

各位达人帮帮忙吧！！

IShape.java
---------------------------
public interface IShape {
    double area();
}

Circle.java
--------------------------
public class Circle implements IShape{
   
    private double radius;
   
    public Circle() {}
   
    public Circle(double radius) {
        super();
        this.radius = radius;
    }

    public double area() {
        return radius*radius*3.14;
        
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

}

Rect.java
-------------------------------------
public class Rect implements IShape {
   
    private double l;
    private double h;
   
    public Rect() {    }

   
    public Rect(double l, double h) {
        super();
        this.l = l;
        this.h = h;
    }

    public double area() {
        return l*h;
    }

    public double getL() {
        return l;
    }

    public void setL(double l) {
        this.l = l;
    }

    public double getH() {
        return h;
    }

    public void setH(double h) {
        this.h = h;
    }

}

TestShape.java
-------------------------------------
public class TestShape {


    public static void main(String[] args) {
        IShape circle = new Circle(3);
        IShape rect = new Rect(3,4);
        if (circle.area()>rect.area() ) {
            System.out.println("circle's area is larger than rect's");
        }else {
            System.out.println("rect's area is larger than circle's");
        }

    }

}

支持LS