目录

1，双向带头循环链表的定义

2，双向带头循环链表的实现

A，函数的声明

B，函数的定义

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1，双向带头循环链表的定义

带头双向循环链表：结构复杂，一般用在单独存储数据。实际中使用的链表数据结构，都是带头双向链表。

2，双向带头循环链表的实现

A，函数的声明

#pragma once
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <stdbool.h>typedef int LTDataType;
typedef struct ListNode//带头双向循环链表
{struct ListNode* prev;struct ListNode* next;LTDataType data;
}LTNode;//void ListInit(ListNode** pphead);//无返回值初始化
//链表初始化/开辟节点/打印链表/遍历长度
LTNode* ListInit();
LTNode* BuyNode(LTDataType x);
void ListPrint(LTNode* phead);
int ListSize(LTNode* phead);//尾插/头插/尾删/头删/间插/间删
void ListPushBack(LTNode* phead, LTDataType x);
void ListPushFront(LTNode* phead, LTDataType x);
void ListPopBack(LTNode* phead);
void ListPopFront(LTNode* phead);
void ListInsertAfter(LTNode* pos, LTDataType x);
void ListErase(LTNode* pos);//查找/销毁
LTNode* ListFind(LTNode* phead, LTDataType x);
void ListDestory(LTNode* phead);

B，函数的定义

LTNode* BuyNode(LTDataType x)
{LTNode* node = (LTNode*)malloc(sizeof(LTNode));if (node == NULL){perror("malloc fail");exit(-1);}node->next = NULL;node->prev = NULL;node->data = x;return node;
}LTNode* ListInit()
{LTNode* phead = BuyNode(-1);phead->prev = phead;phead->next = phead;return phead;
}void ListPushBack(LTNode* phead, LTDataType x)
{assert(phead);LTNode* newnode = BuyNode(x);LTNode* tail = phead->prev;tail->next = newnode;newnode->prev = tail;newnode->next = phead;phead->prev = newnode; 
}void ListPrint(LTNode* phead)
{assert(phead);LTNode* cur = phead->next;while (cur != phead){printf("%d ", cur->data);cur = cur->next;}printf("\n");
}void ListPushFront(LTNode* phead, LTDataType x)
{assert(phead);LTNode* newnode = BuyNode(x);LTNode* next = phead->next;phead->next = newnode;newnode->next = next;newnode->prev = phead;next->prev = newnode;
}void ListPopBack(LTNode* phead)
{assert(phead);assert(phead->next != phead);LTNode* tail = phead->prev;LTNode* tailprev = tail->prev;free(tail);tailprev->next = phead;phead->prev = tailprev;
}void ListPopFront(LTNode* phead)
{assert(phead);assert(phead->next != phead);LTNode* next = phead->next;LTNode* nextnext = next->next;free(next);phead->next = nextnext;nextnext->prev = phead;
}void ListInsertAfter(LTNode* pos, LTDataType x)
{assert(pos);LTNode* newnode = BuyNode(x);LTNode* posprev = pos->prev;posprev->next = newnode;newnode->prev = posprev;newnode->next = pos;pos->prev = newnode;
}void ListErase(LTNode* pos)
{assert(pos);assert(pos->next != pos);LTNode* posprev = pos->prev;LTNode* posnext = pos->next;free(pos);posprev->next = posnext;posnext->prev = posprev;
}LTNode* ListFind(LTNode* phead, LTDataType x)
{assert(phead);assert(phead->next != phead);LTNode* cur = phead->next;while (cur->data != x){cur = cur->next;if (cur == phead){printf("没找到");break;}}return cur;
}int ListSize(LTNode* phead)
{assert(phead);LTNode* cur = phead->next;int size = 0;while (phead){size++;cur = cur->next;}return size;
}void ListDestory(LTNode* phead)
{assert(phead);LTNode* cur = phead->next;int size = 0;while (cur != phead){LTNode* next = cur->next;ListErase(cur);cur = next;}    free(phead);phead = NULL;
}