带头双向循环链表的增删查改

头文件

#include <stdio.h>
#include<stdlib.h>
#include<assert.h>

typedef int LTdAateType;
typedef struct ListNode
{
	LTdAateType data;
	struct  ListNode *next;
	struct ListNode *prev;
}ListNode;

//初始化链表
ListNode *InitListNode();

//尾插链表
void ListPushBack(ListNode* plist, LTdAateType x);

// 双向链表打印
void ListPrint(ListNode* plist);

// 双向链表头插
void ListPushFront(ListNode* plist, LTdAateType x);

// 双向链表尾删
void ListPopBack(ListNode* plist);

// 双向链表头删
void ListPopFront(ListNode* plist);

// 双向链表查找
ListNode* ListFind(ListNode* plist, LTdAateType x);

// 双向链表在pos的前面进行插入
void ListInsert(ListNode* pos, LTdAateType x);

// 双向链表删除pos位置的节点
void ListErase(ListNode* pos);

实现

#include "List.h"

//新建节点
ListNode *BuyListNode(LTdAateType x)
{
	ListNode *NewNode = (struct ListNode*)malloc(sizeof(struct ListNode));
	NewNode->data = x;
	NewNode->next = NULL;
	NewNode->prev = NULL;

	return NewNode;
}

//初始化链表
ListNode *InitListNode()
{
	ListNode *phead = BuyListNode(0);
	phead->next = phead;
	phead->prev = phead;
	return phead;
}

//尾插链表
void ListPushBack(ListNode* plist, LTdAateType x)
{
	assert(plist);

	ListNode *tail = plist->prev;
	ListNode *Newnode = BuyListNode(x);

	tail->next = Newnode;
	Newnode->next = plist;
	Newnode->prev = tail;
	plist->prev = Newnode;

}

// 双向链表打印
void ListPrint(ListNode* plist)
{
	assert(plist);

	ListNode *cur = plist->next;
	while (cur != plist)
	{
		printf("%d ", cur->data);
		cur = cur->next;
	}
	printf("\n");
}

// 双向链表头插
void ListPushFront(ListNode* plist, LTdAateType x)
{
	assert(plist);

	ListNode *first = plist->next;
	ListNode *newnode = BuyListNode(x);
	newnode->next = first;
	newnode->prev = plist;
	plist->next = newnode;
	first->prev = newnode;

}

// 双向链表尾删
void ListPopBack(ListNode* plist)
{
	assert(plist);
	assert(plist->next != plist);

	ListNode *tail = plist->prev;

	plist->prev = tail->prev;
	(tail->prev)->next = plist;

	free(tail);
}

// 双向链表头删
void ListPopFront(ListNode* plist)
{
	assert(plist);
	assert(plist->next != plist);

	ListNode *del = plist->next;
	ListNode *delnext = del->next;
	delnext->prev = plist;
	plist->next = delnext;

	free(del);
}

// 双向链表查找
ListNode* ListFind(ListNode* plist, LTdAateType x)
{
	assert(plist);

	ListNode *cur = plist->next;
	while (cur != plist)
	{
		if (cur->data == x)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

// 双向链表在pos的前面进行插入
void ListInsert(ListNode* pos, LTdAateType x)
{
	assert(pos);

	ListNode *newnode = BuyListNode(x);
	newnode->next = pos;
	(pos->prev)->next = newnode;
	newnode->prev = (pos->prev);
	pos->prev = newnode;

}

// 双向链表删除pos位置的节点
void ListErase(ListNode* pos)
{
	assert(pos);

	ListNode *prev = pos->prev;
	ListNode *next = pos->next;

	prev->next = next;
	next->prev = prev;

}