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 num;
        int sum = 0,count = 0;
        while(true){
            num=scan.nextInt();
            if(num<0)break;
            count++;
            sum+=num;
        }
                //没有下面这行代码的一律不及格
        scan.close();
        if(count>0){
            double avg=(double)sum/count;
            //输出格式为：System.out.println(String.format("%.2f",avg));
            System.out.println(String.format("%.2f",avg));
        }
    }
}