判断一个十进制数是几位数

因为有0的存在，所以循环体部分至少要循环一次。

#include <stdio.h>#include <stdlib.h>int bit_num(int n){    int count = 0;    do    {        n = n / 10;        count++;    }   while (n > 0);    return count;}int main(){    int c = 0;    int num = 0;    int bit = 0;    printf("请输入一个正整数：\n");    scanf("%d",&num);    c = bit_num(num);    printf("bit is %d\n",bit_num(num));    system("pause");    return 0;}