package ch05;
//定义一个圆形，继承Shape抽象类
public class Circle extends Shape {
public Circle(double dim){
super(dim);
}
//实现抽象方法callArea()
public double callArea(){
//返回圆的面积
return 3.14*dim*dim;
}
//实现抽象方法callPerimeter()
public double callPerimeter(){
//返回圆的周长
return 2*3.14*dim;
}
public static void main(String[] args) {
//声明一个Shape对象,指向实现它的子类对象
Shape shape = new Circle(10);
//调用callArea()求圆的面积，并输出
System.out.println("圆的面积是："+shape.callArea());
//调用callPerimeter()求圆的周长，并输出
System.out.println("圆的周长是："+shape.callPerimeter());
}
}
