代码如下:
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; }