题解 | #求平均数#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double num = 0;
        double sum = 0, count = 0;
        double avg;
        while (num >= 0) {
            num = sc.nextDouble();
            if (num >= 0) {
                count++;
                sum += num;
            }
        }
        avg = sum / count;
        System.out.printf("%.2f", avg);
        sc.close();
    }
}