入门练习4-12

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>
int main()
{
  int no;
  int num = 0;
  do
  {
    printf("请输入一个正整数:");
    scanf("%d", &no);
    if (no <= 0)
      printf("请不要输入一个非正整数");
  } while (no <= 0);

  printf("%d的位数是",no);

  while (no > 0)
  {
    no = no / 10;
    ++num;
  }
  printf("%d", num);

  putchar('.');
  return 0;

}