题解 | #求平均数#

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        //write your code here......
       int count = 0;
        double sum = 0;
        double avg;
        while (scan.hasNext()) {
            double num = scan.nextDouble();
            if (num < 0) {
                break;
            }
            count++;

            sum += num;
        }
        avg = sum / count;
        System.out.println(String.format("%.2f", avg));

       

    }
}