题解 | 牛牛的圆
牛牛的圆
https://www.nowcoder.com/practice/75a202e826d048a39824ec694b5ce7e3
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int r = in.nextInt();
double cir = 3.14 * Math.pow(r,2);
System.out.printf("%.2f",cir);
}
}