Java求圆的面积与周长

Question

哪位大神教教我！

Answer 1

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;
    }
    
}