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);
        int n = 0;
        int counter = 0;
        float sum = 0;
        while((n = scan.nextInt()) >= 0)
        {
            sum += n;
            counter++;
        }
        System.out.printf("%.2f",sum/counter);
    }
}