不借助库函数 字符串逆转

char* str_rev (char * string)
{
	char *start = string;
	char *left = string;
	char ch;

	while (*string++) {};       /* find end of string */
	string -= 2;

	while (left < string)
	{
		ch = *left;
		*left++ = *string;
		*string-- = ch;
	}

	return start;
}