单向循环链表接口设计

/**

* @file name: 单向循环链表接口设计

* @brief ：设计单向循环链表，实现各种功能函数并测试

* @author ni456xinmie@163.com

* @date 2024/04/23

* @version 1.0

* @property

* @note

* CopyRight (c) 2023-2024 ni456xinmie@163.com All Right Reseverd

*/

构造单向循环链表结构体

// 指的是单向循环链表中的结点有效数据类型，用户可以根据需要进行修改
typedef int DataType_t;

// 构造单向循环链表的结点,链表中所有结点的数据类型应该是相同的
typedef struct CircularLinkedList
{
	DataType_t data;				 // 结点的数据域
	struct CircularLinkedList *next; // 结点的指针域

} CircLList_t;

创建一个空单向循环链表并初始化

CircLList_t *CircLList_Create()
{
	// 1.创建一个头结点并对头结点申请内存
	CircLList_t *Head = (CircLList_t *)calloc(1, sizeof(CircLList_t));
	if (NULL == Head)
	{
		perror("Calloc memory for Head is Failed");
		exit(-1);
	}
	// 2.对头结点进行初始化，头结点是不存储数据域，指针域指向自身，体现“循环”思想
	Head->next = Head;
	return Head; // 3.把头结点的地址返回即可
}

创建新的结点，并对新结点进行初始化

CircLList_t *CircLList_NewNode(DataType_t data)
{
	// 1.创建一个新结点并对新结点申请内存
	CircLList_t *New = (CircLList_t *)calloc(1, sizeof(CircLList_t));
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return NULL;
	}
	// 2.对新结点的数据域和指针域进行初始化
	New->data = data;
	New->next = NULL;
	return New;
}

功能函数：从首节点进行插入元素

bool CircLList_HeadInsert(CircLList_t *Head, DataType_t data)
{
	CircLList_t *new = CircLList_NewNode(data);
	CircLList_t *tmp = Head->next;
	if (Head->next == Head) // empty list
	{
		Head->next = new;
		new->next = new;
		return true;
	}
	while (tmp->next != Head->next) // normal situation,find the last node
		tmp = tmp->next;
	new->next = Head->next;
	Head->next = new;
	tmp->next = new;
	return true;
}

功能函数：从尾部插入新元素

bool CircLList_TailInsert(CircLList_t *Head, DataType_t data)
{
	CircLList_t *new = CircLList_NewNode(data);
	if (Head->next == Head) // judge is the null
	{
		Head->next = new;
		new->next = new;
		return true;
	}
	CircLList_t *tmp;
	while (tmp->next != Head->next) // when the normal situation,find the last node
		tmp = tmp->next;
	tmp->next = new;
	new->next = Head->next;
	return true;
}

功能函数：从指定位置插入新元素

bool CircLList_DestInsert(CircLList_t *Head, DataType_t destval, DataType_t data)
{
	CircLList_t *tmp = Head->next;
	DataType_t i = Head->data;
	if (Head->next == Head) // judge the empty list
	{
		printf("The list is empty");
		return false;
	}
	CircLList_t *new = CircLList_NewNode(data);
	while (destval != tmp->data && tmp->next != Head->next)
	{
		tmp = tmp->next;
	}
	if (destval == tmp->data)
	{
		new->next = tmp->next;
		tmp->next = new;
		return true;
	}
	else
	{
		printf("There is no destval\n");
		return false;
	}
}

功能函数：遍历打印链表

bool CircLList_Print(CircLList_t *Head)
{
	// 对单向循环链表的头结点的地址进行备份
	CircLList_t *Phead = Head;

	// 判断当前链表是否为空，为空则直接退出
	if (Head->next == Head)
	{
		printf("current linkeflist is empty!\n");
		return false;
	}

	// 从首结点开始遍历
	while (Phead->next)
	{
		// 把头结点的直接后继作为新的头结点
		Phead = Phead->next;

		// 输出头结点的直接后继的数据域
		printf("data = %d\n", Phead->data);

		// 判断是否到达尾结点，尾结点的next指针是指向首结点的地址
		if (Phead->next == Head->next)
		{
			break;
		}
	}
	return true;
}

功能函数：删除首节点

bool CircLList_HeadDel(CircLList_t *Head)
{
	// 对单向循环链表的头结点的地址进行备份
	CircLList_t *Phead = Head->next;
	CircLList_t *tmp = Head->next;
	if (Head->next == Head) // 判断当前链表是否为空，为空则直接退出
	{
		printf("current linkeflist is empty!\n");
		return false;
	}
	while (tmp->next != Head->next) // find the last node
		tmp = tmp->next;
	tmp->next = Phead->next;
	Head->next = Phead->next;
	Phead->next = NULL;
	free(Phead);
	return true;
}

功能函数：删除尾部节点

bool CircLList_TailDel(CircLList_t *Head)
{

	CircLList_t *tmpFormer;
	CircLList_t *tmp = Head->next;
	if (Head->next == Head) // 判断当前链表是否为空，为空则直接退出
	{
		printf("current linkeflist is empty!\n");
		return false;
	}
	while (tmp->next != Head->next) // find the last node
	{
		tmpFormer = tmp;
		tmp = tmp->next;
	}
	tmpFormer->next = Head->next;
	tmp->next = NULL;
	free(tmp);
	return true;
}

功能函数：删除指定位置的节点

bool CircLList_MidDel(CircLList_t *Head, DataType_t destval)
{
	CircLList_t *tmpFormer;
	CircLList_t *tmp = Head->next;
	if (Head->next == Head) // 判断当前链表是否为空，为空则直接退出
	{
		printf("current linkeflist is empty!\n");
		return false;
	}
	while (tmp->data != destval && tmp->next != Head->next) // find the specific node
	{
		tmpFormer = tmp;
		tmp = tmp->next;
	}
	if (tmp->data == destval)
	{
		tmpFormer->next = tmp->next;
		tmp->next = NULL;
		free(tmp);
		return true;
	}
	else
	{
		printf("The is no destival\n");
		return false;
	}
}

主函数，调用并测试各功能函数

int main()
{
	CircLList_t *H = CircLList_Create();
	CircLList_HeadInsert(H, 10);
	CircLList_HeadInsert(H, 20);
	CircLList_HeadInsert(H, 30);
	CircLList_TailInsert(H, 30);
	CircLList_TailInsert(H, 40);
	CircLList_DestInsert(H, 30, 15);
	CircLList_Print(H);
	puts("");
	CircLList_HeadDel(H);
	CircLList_Print(H);
	puts("");
	CircLList_TailDel(H);
	CircLList_Print(H);
	puts("");
	CircLList_MidDel(H, 12);
	CircLList_Print(H);
	return 0;
}