java中设计类Circle计算圆的面积

public class Test13 {
    public static void main(String[] args) {
        Circle p1 = new Circle();
        p1.radius = 3;

        double area = p1.findArea();
        System.out.println(area);

    }
}
class Circle{
    //属性
    double radius;
    //求圆的面积
    public double findArea(){
        return(Math.PI*radius*radius);
    }
}