72.Financial Management

描述

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.

输入

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.

输出

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.

样例输入

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

样例输出

1581.42

 1 #include<stdio.h>
 2 int main(int argc, char const *argv[]) {//char *argv[]是一个字符数组,其大小是int argc,主要用于命令行参数argv[]
 3     double sum = 0, a;
 4     int n = 12;
 5     while(n--) {
 6         scanf("%lf", &a);//%lf双精度浮点型数据（也就是double）的输入格式控制符
 7         sum += a;
 8     }
 9     printf("%.2lf\n", sum/12);
10     return 0;
11 }