Java-圓周長和圓面積的計算

import java.util.Scanner; //載入互動輸入
public class pi
{

/**
* @param args
*/
public static void main(String[] args)
{
// TODO Auto-generated method stub
double r;
Scanner scanner = new Scanner(System.in);
System.out.print("請輸入圓的半徑長度：");
r = scanner.nextInt();
scanner.close();
final double pi = 3.141592654; //final 將常數指定常變數
System.out.println("直徑："+(2*r));
System.out.println("圓周長："+(2*r*pi));
System.out.println("圓面積："+(r*r*pi));


}

}