hdu 4493 Tutor

Tutor

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 1981    Accepted Submission(s): 552

Problem Description

Lilin was a student of Tonghua Normal University. She is studying at University of Chicago now. Besides studying, she worked as a tutor teaching Chinese to Americans. So, she can earn some money per month. At the end of the year, Lilin wants to know his average monthly money to decide whether continue or not. But she is not good at calculation, so she ask for your help. Please write a program to help Lilin to calculate the average money her earned per month.

 

Input

The first line contain one integer T, means the total number of cases. 
Every case will be twelve lines. Each line will contain the money she earned per 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 of money she earned for the twelve months. It will be rounded to the nearest penny, preceded immediately by a dollar sign without tail zero. There will be no other spaces or characters in the output.

 

Sample Input

2 
100.00 
489.12 
12454.12 
1234.10 
823.05 
109.20 
5.27 
1542.25 
839.18 
83.99 
1295.01 
1.75
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00

 

Sample Output

$1581.42 
$100

 

精度问题

题目要求精确到分，即小数点后2位，故应该看小数点第三位的值，然后四舍五入。

把平均值+上0.005，则能够使第三位满5进一。

#include"stdio.h"
#define N 12
int main()
{
    int n,i;
    double a,s;
    scanf("%d",&n);
    while(n--)
    {
        s=0;
        for(i=0;i<N;i++)
        {
            scanf("%lf",&a);
            s+=a;
        }
        s/=12;
        int m=(s+0.005)*100;          //小数点后第三位四舍五入
        if(m%100==0)
            printf("$%.0f
",s);
        else if(m%10==0)
            printf("$%.1f
",s);
        else
            printf("$%.2f
",s);
    }
    return 0;
}

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