数一下 1到 100 的所有整数中出现多少次数字9

代码如下：

#include 
  
   

int Count_9(int num)
{
 int i = 0;
 int count = 0;
 for (i = 0; i <= num; i++)
 {
  int tmp = i;
  while (tmp)
  {
tmp %= 10;
if (tmp == 9)
{
 count++;
}
tmp /= 10;
  }
 }
 return count;
}

int main()
{
 int count = 0;
 int num = 0;
 scanf("%d", &num);
 count = Count_9(num);
 printf("%d\n", count);
 return 0;
}