无头链表二级指针方式实现(C语言描述)

无头链表二级指针方式实现

#include 
#include 
 
//定义链表结构
typedef struct Node {
	int data;
	struct Node* next;
}NODE,*LPNODE;
 
//创建节点
LPNODE createNode(int data) {
	LPNODE newNode = (LPNODE)malloc(sizeof(NODE));
	if (NULL == newNode) {
		printf("数据节点内存申请失败!\n");
		return NULL;
	}
	newNode->data = data;
	newNode->next = NULL;
	return newNode;
}
 
//头插
void insertByHead(LPNODE* headNode, int data) {
	LPNODE newNode = createNode(data);
	if (*headNode == NULL) {
		*headNode = newNode;
	}
	else {
		newNode->next = *headNode;
		*headNode = newNode;
	}
}
 
//尾插
void insertByTail(LPNODE* headNode, int data) {
	LPNODE newNode = createNode(data);
	if (*headNode == NULL) {
		*headNode = newNode;   //插入节点就是头节点
	}
	else {
		LPNODE curNode = *headNode;
		while (curNode->next != NULL) {
			curNode = curNode->next;
		}
		curNode->next = newNode;
	}
}
 
//指定位置插入
void insertAppoint(LPNODE* headNode, int data, int pos) {
	LPNODE newNode = createNode(data);
	LPNODE curNode = *headNode;
	if (*headNode == NULL) {
		*headNode = newNode;
	}
	else {
		while (curNode->next != NULL && --pos) {
			curNode = curNode->next;
		}
		newNode->next = curNode->next;
		curNode->next = newNode;
	}
}
 
//头删
void deleteByHead(LPNODE* headNode) {
	if (*headNode == NULL) {
		printf("链表为空,没有节点可以删除!\n");
		return;
	}
	else {
		LPNODE delNode = *headNode;
		*headNode = delNode->next;
		free(delNode);
		delNode = NULL;
	}
}
 
//尾删
void deleteByTail(LPNODE* headNode) {
	if (*headNode == NULL) {
		printf("链表为空,没有节点可以删除!\n");
		return;
	}
	else {
		LPNODE delNode = *headNode;
		LPNODE preNode = *headNode; //删除节点的前一个节点
		while (delNode->next != NULL) {
			preNode = delNode;
			delNode = delNode->next;
		}
		preNode->next = NULL;
		free(delNode);
		delNode = NULL;
	}
}
 
//指定数据删除
void deleteByAppointData(LPNODE* headNode, int posData) {
	if (*headNode == NULL) {
		printf("链表为空,没有节点可以删除!\n");
		return;
	}
	if ((*headNode)->next == NULL) {   //一个节点
		if ((*headNode)->data == posData)
			deleteByHead(headNode);
		else
			printf("未找到指定节点数据!\n");
	}
	else {
		LPNODE delNode = (*headNode)->next;
		LPNODE preNode = *headNode;
		while (delNode->next != NULL && delNode->data != posData) {
			preNode = delNode;
			delNode = delNode->next;
		}
		preNode->next = delNode->next;
		free(delNode);
		delNode = NULL;
	}
}
 
//查找
LPNODE searchNode(LPNODE headNode, int posData) {
	LPNODE curNode = headNode;
	while (curNode != NULL && curNode->data != posData) {
		curNode = curNode->next;
	}
	return curNode;
}
 
//删除全部指定数据
void deleteAllPosdata(LPNODE* headNode, int posData) {
	while (searchNode(*headNode, posData) != NULL) {
		deleteByAppointData(headNode, posData);
	}
}
 
//销毁链表
void destroyList(LPNODE* headNode) {
	while ((*headNode)->next != NULL) {
		deleteByHead(headNode);
	}
	free(*headNode);
	*headNode = NULL;
}
 
//打印链表
void printList(LPNODE headNode) {
	while (headNode != NULL) {
		printf("%d\t", headNode->data);
		headNode = headNode->next;
	}
	printf("\n");
}
 
int main()
{
	LPNODE list = NULL;
 
	//头插
	insertByHead(&list, 1002);
	insertByHead(&list, 1001);
	printList(list);
 
	//尾插
	for (int i = 0; i < 3; i++)
	{
		insertByTail(&list, 520 + i);
		insertByTail(&list, 520 + i);
	}
	printList(list);
 
	//指定位置插入
	insertAppoint(&list, 1314, 2);
	printList(list);
 
	//头删
	deleteByHead(&list);
	printList(list);
 
	//尾删
	deleteByTail(&list);
	printList(list);
 
	//指定数据删除
	deleteByAppointData(&list, 1314);
	printList(list);
 
	//删除所有指定数据
	deleteAllPosdata(&list, 521);
	printList(list);
 
	if (list != NULL)
		printf("链表未销毁!\n");
 
	//销毁链表
	destroyList(&list);
 
	if (list == NULL)
		printf("链表已销毁!\n");
 
	system("pause");
	return 0;
}