pe 7-3 读取整数，报告.txt

c primer 部分习题答案

#include <stdio.h>
 
int main(void)    
{
     int n;
     double sumeven = 0.0;
     int ct_even = 0;
     double sumodd = 0.0;
     int ct_odd = 0;
      
     while (scanf("%d", &n) == 1 && n != 0)
     {
         if (n % 2 == 1)
         {
             sumodd += n;
             ++ct_odd;
         }
         else
         {
             sumeven += n;
             ++ct_even;
         }
     }
     printf("Number of evens: %d", ct_even);
     if (ct_even > 0)
         printf("  average: %g", sumeven / ct_even);
     putchar('\n');
         
    printf("Number of odds: %d", ct_odd);
     if (ct_odd > 0)
         printf("  average: %g", sumodd / ct_odd);
     putchar('\n');
     printf("\ndone\n");
     
    return 0;
}