编辑代码

package www;
import java.util.Scanner;

class yyy {
   public static void main(String[] args) {
  // TODO Auto-generated method stub
    Scanner input = new Scanner(System.in);
    System.out.print("5");
    int r = input.nextInt();
    double pai = Math.PI;
    double result =pai*r*r;
    System.out.println("圆的面积为："+result);