数据结构_带头双向循环链表

List.h

相较于之前的顺序表和单向链表，双向链表的逻辑结构稍微复杂一些，但是在实现各种接口的时候是很简单的。因为不用找尾，写起来会舒服一点。（也可能是因为最近一直在写这个的原因）

#pragma once
#include<stdio.h>
#include<assert.h>
#include<stdlib.h>
#include<stdbool.h>typedef int LTDataType;
typedef struct ListNode
{struct ListNode* prev;LTDataType data;struct ListNode* next;}LTNode;LTNode* LTInit();
void LTDestroy(LTNode* phead);
void LTPrint(LTNode* phead);
//bool LTEmpty(LTNode* phead);void LTPushBack(LTNode* phead, LTDataType x);
void LTPopBack(LTNode* phead);void LTPushFront(LTNode* phead, LTDataType x);
void LTPopFront(LTNode* phead);
//在pos位置之后插入数据
void LTInsert(LTNode* pos, LTDataType x);
void LTErase(LTNode* pos);
LTNode* LTFind(LTNode* phead, LTDataType x);

List.c

在实现接口的时候，除了没有找尾，其他的操作和单向链表是差不多的，这里就不多说了。(注意代码里的注释)

#define _CRT_SECURE_NO_WARNINGS 1#include"List.h"LTNode* BuyNode(LTDataType x)
{LTNode* node = (LTNode*)malloc(sizeof(LTNode));if (node == NULL){perror("malloc is fail!");exit(1);}node->data = x;node->prev = node->next = node;return node;
}LTNode* LTInit()
{LTNode* phead = BuyNode(-1);return phead;
}void LTPrint(LTNode* phead)
{assert(phead);LTNode* pcur = phead->next;while (pcur != phead){printf("%d->",pcur->data);pcur = pcur->next;}printf("\n");//注意换行
}void LTPushBack(LTNode* phead, LTDataType x)
{assert(phead);LTNode* newnode = BuyNode(x);newnode->prev = phead->prev;newnode->next = phead;newnode->prev->next = newnode;phead->prev = newnode;
}void LTPopBack(LTNode* phead)
{assert(phead && phead->next != phead);//第二个很容易忽视！LTNode* del = phead->prev;del->prev->next = phead;phead->prev = del->prev;free(del);del = NULL;
}void LTPushFront(LTNode* phead, LTDataType x)
{assert(phead);LTNode* newnode = BuyNode(x);phead->next->prev = newnode;newnode->next = phead->next;phead->next = newnode;newnode->prev = phead;
}void LTPopFront(LTNode* phead)
{assert(phead && phead->next != phead);LTNode* del = phead->next;del->next->prev = phead;phead->next = del->next;free(del);del = NULL;
}LTNode* LTFind(LTNode* phead, LTDataType x)
{assert(phead && phead->next != phead);LTNode* pcur = phead->next;while (pcur != phead){if (pcur->data == x)//别忘了连等号！！！return pcur;pcur = pcur->next;}return NULL;
}void LTErase(LTNode* pos)
{assert(pos);pos->next->prev = pos->prev;pos->prev->next = pos->next;free(pos);pos = NULL;
}void LTInsert(LTNode* pos, LTDataType x)
{assert(pos);LTNode* newnode = BuyNode(x);pos->next->prev = newnode;newnode->next = pos->next;newnode->prev = pos;pos->next = newnode;
}void LTDestroy(LTNode* phead)//理论上这里应该传二级指针，但是为了保持接口的一致性，用一级。
{assert(phead);LTNode* des = phead->next;while (des != phead){LTNode* next = des->next;free(des);des = next;}free(phead);phead = des = NULL;
}

本博客旨在记录学习过程，以后忘了随时来看。