Java求圆的面积

以下是相关代码：

import java.util.Scanner;

public class asf {
    public static void main(String[] args) {
        double r,s,PI;
        PI = 3.14;
        System.out.print("r=");
        Scanner sc = new Scanner(System.in);
        r = sc.nextDouble();
        s = PI * r * r;
        System.out.println("s = "+s);
    }
}

运行结果：