范围，出现的数字可以替换

#include<stdio.h>#include<stdlib.h>int main(){ int n,y,m; int sum = 0;//计数器 for (n = 1; n <= 100; n++) { m = n;//把n赋值给m while (m > 0) { y = m % 10; m = m / 10; if (y == 9) sum++; } } printf("%d",sum); return 0;}