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📋专栏：算法
🔑本章内容：[数据结构]—链表之带头双向循环链表
送给各位💌：就算星星碎了溢出来的光也会很好看.
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提示：以下是本篇文章正文内容，下面案例可供参考

🌟一、带头双向循环链表

==带头双向循环链表：==结构最复杂，一般用在单独存储数据。实际中使用的链表数据结构，都是带头双向循环链表。另外这个结构虽然结构复杂，但是使用代码实现以后会发现结构会带来很多优势，实现反而简单了。
链表有多种结构详细请看：
【数据结构】- 链表之单链表(上)

🌟二、带头双向循环链表结构图：

🌟三、带头双向循环链表代码实现：

🌏3.1头插：

void LTPushFornt(LTNode* phead, LTDataType x)
{
	LTNode* newnode = BuyLTNode(x);
	LTNode* cur = phead->next;
	newnode->prev = phead;
	phead->next = newnode;
	newnode->next = cur;
	cur->prev = newnode;
}

🌏3.2头插流程图

🌏3.3 尾插

void LTPushBack(LTNode* phead, LTDataType x)
{
	assert(phead);
	LTNode* newnode = BuyLTNode(x);
	LTNode* tail = phead->prev;
	tail->next = newnode;
	newnode->prev = tail;
	newnode->next = phead;
	phead->prev = newnode;
}

🌏3.4尾插流程图

🌏3.5全部代码：

//List.h
#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>

typedef int LTDataType;
typedef struct ListNode
{
	struct ListNode* next;
	struct ListNode* prev;
	LTDataType data;
}LTNode;

LTNode* LTInit();
void LTPushFornt(LTNode* phead, LTDataType x);
void LTPushBack(LTNode* phead, LTDataType x);
void LTNodePrint(LTNode* phead);
//List.c
#define _CRT_SECURE_NO_WARNINGS 1
#include"List.h"
LTNode* BuyLTNode(LTDataType x)
{
	LTNode* newnode = (LTNode*)malloc(sizeof(LTNode));
	if (newnode == NULL)
	{
		perror("malloc fail");
	}
	newnode->data = x;
	newnode->next = NULL;
	newnode->prev = NULL;
}
LTNode* LTInit()
{
	LTNode* phead = BuyLTNode(-1);
	phead->next = phead;
	phead->prev = phead;
	return phead;
}

void LTNodePrint(LTNode* phead)
{
	assert(phead);
	LTNode* cur = phead->next;
	printf("哨兵位<==>");
	while (cur != phead)
	{
		printf("%d<==>", cur->data);
		cur = cur->next;
	}
	printf("\n");
}

void LTPushFornt(LTNode* phead, LTDataType x)
{
	LTNode* newnode = BuyLTNode(x);
	LTNode* cur = phead->next;
	newnode->prev = phead;
	phead->next = newnode;
	newnode->next = cur;
	cur->prev = newnode;
}

void LTPushBack(LTNode* phead, LTDataType x)
{
	assert(phead);
	LTNode* newnode = BuyLTNode(x);
	LTNode* tail = phead->prev;
	tail->next = newnode;
	newnode->prev = tail;
	newnode->next = phead;
	phead->prev = newnode;
}
//Test.c
#define _CRT_SECURE_NO_WARNINGS 1
#include"List.h"
void TestList()
{
	LTNode* plist = LTInit();
	LTPushBack(plist, 1);
	LTPushBack(plist, 2);
	LTPushBack(plist, 3);
	LTPushBack(plist, 4);
	LTNodePrint(plist);
}
int main()
{
	TestList();
	return 0;
}