c - 为什么它不能正确计算成员的平均值？

Question

这是代码:

#include <stdio.h>

int group, regular_group, regular_members, shutdown, special_group,
    special_members;
float average_special, average_regular;
main()
{
  do
  {
    printf("How many members are in the group?\n");
    scanf("%d", &group);

    if (group >= 15)
    {
      regular_group = regular_group + 1;
      regular_members = regular_members + group;
      printf("Do you want to add another group? yes = 1, no = 0 \n");
      scanf("%d", &shutdown);
    }

    else
    {
      special_group = special_group + 1;
      special_members = special_members + group;
      printf("Do you want to add another group? yes = 1, no = 0 \n");
      scanf("%d", &shutdown);
    }
  }

  while (shutdown == 1);

  average_regular = regular_members / regular_group;
  average_special = special_members / special_group;

  printf("\nTotal regular members:\n%d\n", regular_members);
  printf("\nTotal special members:\n%d\n", special_members);

  printf("\nAverage regular members in a group:\n%f\n", average_regular);
  printf("\nAverage special members in a group:\n%f\n", average_special);
  fflush(stdin);
  getchar();

}

如果一个组大于 15，则自动成为常规组，但如果小于 15，则自动成为特殊组。我需要每个类别的内存总数。成员总数工作正常。但我还需要一组这两个类别的平均大小。但平均值始终为 0,000000。但是我找不到错误..请帮助我

非常感谢!

Answer 1

这是因为

1. 您将两个整数相除 regular_members/regular_group，相除后得到一个整数。如果分子将变得小于分母，那么您将得到 0 作为结果。
2. 您没有初始化变量 regular_group、regular_members、special_group、special_members、average_special和average_regular。

而不是使用

average_regular = regular_members/regular_group;
average_special = special_members/special_group;

试试这个

average_regular = (float)regular_members/regular_group;
average_special = (float)special_members/special_group;

同时删除 fflush(stdin)。它将调用未定义的行为。
声明你的变量

int group, regular_group, regular_members, shutdown, special_group,
special_members;
float average_special, average_regular;

在 main 函数中

main()
{
     int group, regular_group, regular_members, shutdown, special_group, special_members;
     float average_special, average_regular;
     ....
     ....
}

并且不要忘记初始化变量:regular_group、regular_members、special_group、special_members 、average_special、average_regular 到 0。

---

这是你的工作代码(经过一些修改)

#include <stdio.h>

int main()
{
    int group, regular_group = 0, regular_members = 0, shutdown, special_group = 0,
    special_members = 0;
    float average_special = 0, average_regular = 0;

  do
  {
        printf("How many members are in the group?\n");
        scanf("%d", &group);

        if (group >= 15)
        {
            regular_group = regular_group + 1;
            regular_members = regular_members + group;
            printf("Do you want to add another group? yes = 1, no = 0 \n");
            scanf("%d", &shutdown);
        }

        else
        {
            special_group = special_group + 1;
            special_members = special_members + group;
            printf("Do you want to add another group? yes = 1, no = 0 \n");
            scanf("%d", &shutdown);
       }
  } while (shutdown != 0);

if(regular_group != 0)              //to stop division by zero
    average_regular = (float)regular_members / regular_group;
if(special_group != 0)              //to stop division by zero  
    average_special = (float)special_members / special_group;

printf("\nTotal regular members:\n%d\n", regular_members);
printf("\nTotal special members:\n%d\n", special_members);

printf("\nAverage regular members in a group:\n%f\n", average_regular);
printf("\nAverage special members in a group:\n%f\n", average_special);

return 0;

}