代码：class Circle{

  double radius;

  double getArea(){

   double area=3.14*radius*radius;

   return area;

   }

  }

public class Example4_2{

  public  static void main(String[] args){

    Circle circle =new Circle();

   circle.radius=12.23;

   double area=circle.getArea();

   System.out.printf("半径是%5.3f的圆的面积是：\n%5.3f\n",circle.radius,area);

   }

  }