【初学数据结构】双向链表

大家好呀！这个是付青云同学的博客！
目前一直在学习C语言。
写博客是为了来记录我的学习过程，同时也希望通过博客能够帮助到需要帮助的人。
如果我的博客可以帮助到你，不妨给我一个关注哦

前面实现了单链表

• 双向链表
• • 声明部分
  • 函数实现部分
• 总结
• • 单链表与双向链表

#pragma once

#include 
#include 
#include 

typedef int LTDateType;

typedef struct ListNode 
{
	LTDateType data;
	struct ListNode* next;
	struct ListNode* prev;
}LTNode;

//初始化
LTNode* ListInit(LTNode* phead);
//创建新节点
LTNode* BuyListNode(LTDateType x);
//打印
void ListPrint(LTNode* phead);
//尾插
void ListPushBack(LTNode* phead, LTDateType x);
//尾删
void ListPopBack(LTNode* phead);
//头插
void ListPushFront(LTNode* phead, LTDateType x);
//头删
void ListPopFront(LTNode* phead);
//查找
LTNode* ListFind(LTNode* phead, LTDateType x);
//x位置之后插入
void ListInsertBack(LTNode* pos, LTDateType x);
//x位置之前插入
void ListInsertFront(LTNode* pos, LTDateType x);
//删除
void ListErast(LTNode* pos);
//删除所有链表
void ListDestroy(LTNode* phead);

#define _CRT_SECURE_NO_WARNINGS

#include "List.h"


LTNode* BuyListNode(LTDateType x)
{
	LTNode* newnode = (LTNode*)malloc(sizeof(LTNode));
	newnode->data = x;
	newnode->next = NULL;
	newnode->prev = NULL;

	return newnode;
}

void ListPrint(LTNode* phead)
{
	assert(phead);

	LTNode* cur = phead->next;

	while (cur != phead)
	{
		printf("%d ", cur->data);
		cur = cur->next;
	}
}

LTNode* ListInit(LTNode* phead)
{
	//哨兵位头节点
	phead = (LTNode*)malloc(sizeof(LTNode));
	phead->next = phead;
	phead->prev = phead;

	return phead;
}

void ListPushBack(LTNode* phead, LTDateType x)
{
	

	ListInsertFront(phead, x);


}

void ListPopBack(LTNode* phead)
{
	

	ListErast(phead->prev);

}

void ListPushFront(LTNode* phead, LTDateType x)
{
	

	ListInsertBack(phead, x);

}

void ListPopFront(LTNode* phead)
{
	

	ListErast(phead->next);

}

LTNode* ListFind(LTNode* phead, LTDateType x)
{
	assert(phead);

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

void ListInsertBack(LTNode* pos, LTDateType x)
{
	assert(pos);

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

}

void ListInsertFront(LTNode* pos, LTDateType x)
{
	assert(pos);

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

}

void ListErast(LTNode* pos)
{
	assert(pos);
	assert(pos != pos->next);

	LTNode* cur = pos->next;
	cur->prev = pos->prev;
	pos->prev->next = cur;
	
	free(pos);
	pos = NULL;
	free(pos);
}

void ListDestroy(LTNode* phead)
{
	assert(phead);

	LTNode* cur = phead->next;
	while (cur != phead)
	{
		LTNode* next = cur;
		cur = cur->next;
		free(next);
	}
	free(phead);
}

虽说都是链表，在结构上双向链表看起来比单链表复杂了，但是实现起来它比单链表方便多了。