题目要求输入一行整数直到输入0，然后计算奇数和偶数(0除外)的个数以及求出它们的平均值。
#include<stdio.h>
int main(void)
{
    int a;
    int n_even = 0;
    int n_odd = 0;
    int sum_even = 0;
    int sum_odd = 0;
    float average_even;
    float average_odd;
   
    while(scanf("%d",&a)==1)
    {
   
        if((a%2)==0 && a!='0')
        {
            
          n_even++;
          sum_even+=a;
        }  
          else
          {
            n_odd++;
            sum_odd+=a;
          }
            
        
    }
    average_even=sum_even/n_even;
    average_odd=sum_odd/n_odd;
    printf("there are %d even number,%d odd number.\n",n_even,n_odd);
    printf("the average of all even numbers is %.1f.\n",average_even);
    printf("the average of all odd numbers is %.1f.\n",average_odd);
    return 0;
}