7-137 Average (10分)

7-137 Average (10分)

 

You are going to read a serial of none-negative integers, which ends with a negative number that does not count as one of the data. Your program calculates the average of all the none-negative integers, and prints the average which rounds to two decimal places.

When there's no valid data at all, your program prints out:

None

输入格式：

A serial of none-negative integers, ending with a negative number, which is not one of the valide data.

输出格式：

A number rounds to two decimal places, which is the average of the serial.

The printf for this case is:

printf("%.2f\n", (double)sum/count);

输入例子

1 2 3 4 5 6 -1

 

输出例子

3.50


#include<stdio.h>
int main()
{
 int n;
 int sum=0;
 int count=0;
 int temp;
 
 while(scanf("%d",&temp)&&temp>=0)
 {
  sum+=temp;
  count++;
  
 }
 if(count)
 {
  printf("%.2f\n", (double)sum/count);
 }
 else
 printf("None\n");
 return 0;
}