#include
int main() {
int n;
int sum = 0;
int count = 0;
printf("请输入一个正整数n:");
scanf("%d", &n);
for (int i = 1; i <= n; i++) {
int num = i;
int digit_sum = 0;
while (num != 0) {
digit_sum += num % 10;
num /= 10;
}
if (digit_sum == 9) {
sum += i;
count++;
}
}
if (count == 0) {
printf("1-%d中没有各位数字之和为9的数\n", n);
} else {
printf("1-%d中各位数字之和为9的数的平均值为%.2f\n", n, (float)sum / count);
}
return 0;
}