ACMラーニング-POJ-1004-Financial Management

菜鳥はACMを学び、自分の成長過程の点滴を記録する.
勉強の道中、君と一緒に勉強する.
ACMラーニング-POJ-1003-Financial Management
Financial Management
Time Limit: 1000MS
 
Memory Limit: 10000K
Total Submissions: 109412
 
Accepted: 51958
Description
Larry graduated this year and finally has a job. He's making a lot of money, but somehow never seems to have enough. Larry has decided that he needs to grab hold of his financial portfolio and solve his financing problems. The first step is to figure out what's been going on with his money. Larry has his bank account statements and wants to see how much money he has. Help Larry by writing a program to take his closing balance from each of the past twelve months and calculate his average account balance.
Input
The input will be twelve lines. Each line will contain the closing balance of his bank account for a particular month. Each number will be positive and displayed to the penny. No dollar sign will be included.
Output
The output will be a single number, the average (mean) of the closing balances for the twelve months. It will be rounded to the nearest penny, preceded immediately by a dollar sign, and followed by the end-of-line. There will be no other spaces or characters in the output.
Sample Input

100.00
489.12
12454.12
1234.10
823.05
109.20
5.27
1542.25
839.18
83.99
1295.01
1.75

Sample Output

$1581.42

Source
Mid-Atlantic 2001
質問:
12個の数の平均数を求めます.
問題の分析:
.....この問題を見て、急におしっこをしました.私がテーマを作ったのはAC率を見て手を出したのです.50%から徐々に練習を始める.しかし、このAC率48%のテーマは、確かに水でいいです.牛たちはこれをするのを潔しとしないだろう.はい、これも特に注意する必要はありません.タイプチェンジのときに気をつければいいのです.直接コードをつけましょう.

#include 

int main()
{
    int n = 0;
    double sum_ = 0.0;
    double each_month;
    
    while (~scanf("%lf", &each_month) && n < 12)
    {
        sum_ += each_month;
        n++;
        if (n==12)
        {
            printf("$%.2lf
", sum_/(double)n);
            break;
        }
    }
    return 0;
}