输入圆的半径，得出圆的周长和面积

 

import java.util.*;

public class Main{
    public static void main(String[] args) {
        Circle circle=new Circle();
        Scanner scanner=new Scanner(System.in);
        circle.r= scanner.nextDouble();
        System.out.println(circle.getS());
    }
}

class Circle{
    double r,s;
    public static final double pi=3.14;
    double getS(){
        s=r*r*pi;
        return s;
    }
}