C语言之字符串逆序函数的三种实现方式

//对一个字符串进行逆序
int main()
{
    char arr[1000] = { 0 };
    gets(arr);
    int len = strlen(arr);
    char* left = arr;
    char* right = arr + len - 1;
    while (left < right)
    {
        char* tmp = *left;
        *left = *right;
        *right = tmp;
        left++;
        right--;
    }
    printf("%s\n", arr);
    return 0;
}

//写一个函数（非递归）实现逆序字符串
void severse_string(char* str)
{
	int len = strlen(str);
	char* left = str;
	char* right = str + len - 1;
	while (left < right)
	{
		char tmp = *left;
		*left = *right;
		*right = tmp;
		left++;
		right--;
	}
}
int main()
{
	char arr[] = "abcdef";
	severse_string(arr);
	printf("%s\n", arr);
	return 0;
}

 //用数组函数的方法（非递归）实现字符串的逆序打印
void severse_string(char arr[])
{
	int len = strlen(arr);
	int left = 0;
	int right = len - 1;
	while (left < right)
	{
		char tmp = arr[left];
		arr[left] = arr[right];
		arr[right] = tmp;
		left++;
		right--;
	}
}
int main()
{
	char arr[] = "abcdef";
	severse_string(arr);
	printf("%s\n", arr);
	return 0;
}

//用递归的（函数）的方法实现对字符串的逆序打印
void reverse_string(char* str)
{
	int len = strlen(str);
	char tmp = *str;
	*str = *(str + len - 1);
	*(str + len - 1) = '\0';

	if ((strlen(str + 1)) >= 2)
	{
		reverse_string(str + 1);
	}
	*(str + len - 1) = tmp;
}
int main()
{
	char arr[] = "abcdef";
	reverse_string(arr);
	printf("%s\n", arr);
	return 0;
}

void reverse_string(char* l, char* r)
{
	while (l < r)
	{
		char tmp = *l;
		*l = *r;
		*r = tmp;
		l++;
		r--;
	}
}
int main()
{
	char arr[100] = { 0 };
	//输入数组
	gets(arr);
	//计算数组的大小
	int len = strlen(arr);
	char* left = arr;
	char* right = left + len - 1;
	reverse_string(left, right);
	//对单词进行逆序
	char* start = arr;
	char* cur = arr;
	while (*cur!='\0')
	{
		while (*cur != ' ' && *cur!='\0')
		{
			cur++;
		}
		reverse_string(start, cur - 1);
		start = cur + 1;
		if (*cur != '\0')
		{
			cur++;//cui原来是空格
		}
	}
	printf("%s\n", arr);
	return 0;
}