Java求圆的面积与周长

哪位大神教教我！

import java.util.Scanner;

public class 圆的周长与面积 {

    public static void main(String[] args) {

        int r = 0;
        Scanner in = new Scanner(System.in);
        System.out.println("请输入圆的半径：");
        r = in.nextInt();
        Circle c = new Circle(r);
        System.out.println("半径为"+r+"的圆的面积：="+c.circleArea());
        System.out.println("半径为"+r+"的圆的周长："+c.circlePerim());
        
    }

}
class Circle{
    public static double PI=3.14;
    private double r;
    public Circle() {}
    public Circle(double r) {
        this.r = r;
    }
    public double getR() {
        return r;
    }
    public void setR(double r) {
        this.r = r;
    }
    public double circleArea() {
        return PI*r*r;
    }
    public double circlePerim() {
        return PI*2*r;
    }
    
}

package m0_650;

public class circle {
    private double r;
    private double pi = 3.14;

    public circle(double r) {
        // TODO Auto-generated constructor stub
        this.r = r;
    }

    public void circleArea() {
        System.out.println("半径为"+r+"的圆的面积是："+(pi*r*r));
    }

    public void circlePerim() {
        System.out.println("半径为"+r+"的圆的周长是："+(2*pi*r));
    }
}

package m0_650;

import java.util.Scanner;

public class test {
public static void main(String[] args) {
    @SuppressWarnings("resource")
    Scanner sc =new Scanner(System.in);
    System.out.print("请输入圆的半径：");
    circle c = new circle(sc.nextDouble());
    c.circleArea();
    c.circlePerim();
}
}

有不明白的地方，留言啊。

自己写吧 这个动手才能学习
就是新建一个圆类
构造函数带个半径参数
然后计算面积就是3.14rr
周长3.14r2

主函数新建圆的对象 掉用两个方法