判断一个字符串是否为回文数字符串

#include<stdio.h>
#define STRLEN 100

int Is_palindromic_str(char *str)
{
	int left = 0;//字符串数组的第一个字母的下标
	int i = 0;
	while(str[i] != '\0')
	{
		i++;
	}
	int right = i - 1;//字符串数组最后一个字母（非‘\0’）的下标
	while(left <= right)
	{
		if(str[left] == str[right])//判断左右字符是否一致，一致的话判断下一个
		{
			left++;
			right--;
		}
		else 
			return -1;//不一致，表明不是回文数字符串
	}
	return 1;
}

int main()
{
	char str[STRLEN];
	int i = 1; //循环控制的条件
	while(i)
	{
		printf("Please input the str you want to judge:\n");
		scanf("%s",str);

		if(Is_palindromic_str(str) != -1)
		{
			printf("It's a palidromic string!\n");
		}
		else
		{
			printf("It's not a palidromic string!\n");
		}
		printf("continue:1,break:0\n");
		scanf("%d",&i);
	}
	return 0;
}