c语言简单实现双向链表

文章目录

• 一、什么是双向链表
• 二、双向链表的功能
• 三、双向链表的实现

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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、什么是双向链表

双向链表也叫双链表，是链表的一种，它的每个数据结点中都有两个指针，分别指向直接后继和直接前驱。所以，从双向链表中的任意一个结点开始，都可以很方便地访问它的前驱结点和后继结点。一般我们都构造双向循环链表。（如下图所示）

 

！！！一般而言双向链表分为带哨兵位双向链表和不带哨兵位双向链表，这里说的是带哨兵位双向链表！！！

 

 

二、双向链表的功能

1.构建双向链表的节点

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

} LTNode;

 

2.各项功能

LTNode* ListInit();//初始化
void Listprint(LTNode* phead);//打印
void ListPushBack(LTNode* phead, LTDataType X);//尾插
void ListPushFront(LTNode* phead, LTDataType X);//头插
void ListPopBack(LTNode* phead);//尾删
void ListPopFront(LTNode* phead);//头删
bool ListEmpty(LTNode* phead);//防止删空
size_t ListSize(LTNode* phead);//个数
LTNode* ListFind(LTNode* phead, LTDataType X);//寻找指针-在pos之前
void ListInsert(LTNode* phead, LTDataType X);//插入指针-在pos之前
void ListEarse(LTNode* phead);//删除pos
void ListDestory(LTNode* phead);//销毁

初始化

LTNode* ListInit()//初始化
{
	LTNode* guard =(LTNode*) malloc(sizeof(LTNode));
	if (guard == NULL)
	{
		perror("malloc failed");
		exit(-1);
	}
	guard->next = guard;
	guard->prev = guard;
	return guard;
}

打印

void Listprint(LTNode* phead)//打印
{
	assert(phead);//断言链表不为空
	LTNode* cur = phead->next;//记录下一个方便迭代
	printf("phead");
	while (cur != phead)//迭代
	{
		printf("<=>%d<=>", cur->data);
		cur = cur->next;
	}
	printf("\n");
}

尾插

void ListPushBack(LTNode* phead, LTDataType X)//尾插
{
	assert(phead);
	LTNode* newnode = BuyNewnode(X);
	LTNode* tail = phead->prev;
	tail->next = newnode;
	newnode->next = phead;
	newnode->prev = tail;
	phead->prev = newnode;
	/* ListInsert( phead, X);*///在哨兵位之前插入（使用插入函数）等于尾插
}

 

 

 

 

头插

void ListPushFront(LTNode* phead, LTDataType X)//头插
{
	assert(phead);
	LTNode* newnode = BuyNewnode(X);
	//建立临时节点记录phead下一个指针可不注意顺序
	phead->next->prev = newnode;
	newnode->next = phead->next;
	newnode->prev = phead;
	phead->next = newnode;
	//ListInsert(phead->next, X);//在哨兵位之后插入等于头插
}

 

尾删

void ListPopBack(LTNode* phead)//尾删
{
	assert(phead);
	assert(! ListEmpty(phead));
	LTNode* cur = phead->prev;
	phead->prev = phead->prev->prev;
	phead->prev->next = phead;
	free(cur);
	cur = NULL;
	/*ListEarse(phead->prev);*///删除phead的前一个为尾删
}

头删

void ListPopFront(LTNode* phead)//头删
{
	assert(phead);
	assert(!ListEmpty(phead));
	LTNode* cur = phead->next;
	phead->next = phead->next->next;
	phead->next->prev = phead;
	free(cur);
	cur= NULL;
	//ListEarse(phead->next);//删除phead的下一个位头删
}

防止删空

bool ListEmpty(LTNode* phead)
{
	assert(phead);

	/*if (phead->next == phead)
		return true;
	else
		return false;*/

	return phead->next == phead;
}

求个数

size_t ListSize(LTNode* phead)//记录个数
{
	assert(phead);
	size_t n = 0;
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		++n;
		cur = cur->next;
	}
	return n;
	printf("\n");
 }

寻找函数

LTNode* ListFind(LTNode* phead, LTDataType X)//寻找（找到的位置为pos的位置）
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		if (cur->data == X)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

插入函数-在pos之前插入

void ListInsert(LTNode*pos,LTDataType X)//在po之前插入
{
	assert(pos);
	LTNode* prev = pos->prev;
	LTNode* newnode = BuyNewnode(X);
	pos->prev = newnode;
	newnode->next = pos;
	newnode->prev = prev;
	prev->next = newnode;
}

删除函数-删除pos

void ListEarse(LTNode* pos)//删除pos
{
	assert(pos);
	LTNode* cur = pos->prev;
	LTNode* tail = pos->next;
	cur->next = tail;
	tail->prev = cur;
	free(pos);
//	pos = NULL;
}

销毁

//可以设置二级指针直接把phead置空；建议：使用一级指针，保持接口一致性，让ListDestory的人置空
void ListDestory(LTNode* phead)
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		LTNode* next = cur->next;
		free(cur);
		cur = next;
	}
	free(phead);
}

三、双向链表的实现

List.h

#pragma once
#include
#include
#include
#include
#include
typedef int LTDataType;
typedef struct ListNode
{
	struct ListNode* next;
	struct ListNode* prev;
	LTDataType data;

} LTNode;

LTNode* ListInit();//初始化
void Listprint(LTNode* phead);//打印
void ListPushBack(LTNode* phead, LTDataType X);//尾插
void ListPushFront(LTNode* phead, LTDataType X);//头插
void ListPopBack(LTNode* phead);//尾删
void ListPopFront(LTNode* phead);//头删
bool ListEmpty(LTNode* phead);//防止删空
size_t ListSize(LTNode* phead);//个数
LTNode* ListFind(LTNode* phead, LTDataType X);//寻找指针
void ListInsert(LTNode* phead, LTDataType X);//插入指针-在pos之前
void ListEarse(LTNode* phead);//删除pos
void ListDestory(LTNode* phead);//销毁

List.c

#include"List.h";
LTNode* ListInit()//初始化
{
	LTNode* guard =(LTNode*) malloc(sizeof(LTNode));
	if (guard == NULL)
	{
		perror("malloc failed");
		exit(-1);
	}
	guard->next = guard;
	guard->prev = guard;
	return guard;
}
LTNode* BuyNewnode(X)
{
	LTNode* newnode = (LTNode*)malloc(sizeof(LTNode));//建立新节点
	if (newnode == NULL)
	{
		perror("malloc failed");
		exit(-1);
	}
	newnode->data = X;
	newnode->next = NULL;
	newnode->prev = NULL;
	return newnode;
}
void ListPushBack(LTNode* phead, LTDataType X)//尾插
{
	assert(phead);
	LTNode* newnode = BuyNewnode(X);
	LTNode* tail = phead->prev;
	tail->next = newnode;
	newnode->next = phead;
	newnode->prev = tail;
	phead->prev = newnode;
	/* ListInsert( phead, X);*///在哨兵位之前插入等于尾插
}

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

void ListPushFront(LTNode* phead, LTDataType X)//头插
{
	assert(phead);
	LTNode* newnode = BuyNewnode(X);
	//建立临时节点记录phead下一个指针可不注意顺序
	phead->next->prev = newnode;
	newnode->next = phead->next;
	newnode->prev = phead;
	phead->next = newnode;
	//ListInsert(phead->next, X);//在哨兵位之后插入等于头插
}
void ListPopBack(LTNode* phead)//尾删
{
	assert(phead);
	assert(! ListEmpty(phead));
	LTNode* cur = phead->prev;
	phead->prev = phead->prev->prev;
	phead->prev->next = phead;
	free(cur);
	cur = NULL;
	/*ListEarse(phead->prev);*///删除phead的前一个为尾删
}
void ListPopFront(LTNode* phead)//头删
{
	assert(phead);
	assert(!ListEmpty(phead));
	LTNode* cur = phead->next;
	phead->next = phead->next->next;
	phead->next->prev = phead;
	free(cur);
	cur= NULL;
	//ListEarse(phead->next);//删除phead的下一个位头删
}
bool ListEmpty(LTNode* phead)
{
	assert(phead);

	/*if (phead->next == phead)
		return true;
	else
		return false;*/

	return phead->next == phead;
}
size_t ListSize(LTNode* phead)//记录个数
{
	assert(phead);
	size_t n = 0;
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		++n;
		cur = cur->next;
	}
	return n;
	printf("\n");
 }

LTNode* ListFind(LTNode* phead, LTDataType X)//寻找
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		if (cur->data == X)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

void ListInsert(LTNode*pos,LTDataType X)//在po之前插入
{
	assert(pos);
	LTNode* prev = pos->prev;
	LTNode* newnode = BuyNewnode(X);
	pos->prev = newnode;
	newnode->next = pos;
	newnode->prev = prev;
	prev->next = newnode;
}

void ListEarse(LTNode* pos)//删除pos
{
	assert(pos);
	LTNode* cur = pos->prev;
	LTNode* tail = pos->next;
	cur->next = tail;
	tail->prev = cur;
	free(pos);
//	pos = NULL;
}
//可以设置二级指针直接把phead置空；建议：使用一级指针，保持接口一致性，让ListDestory的人置空
void ListDestory(LTNode* phead)
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		LTNode* next = cur->next;
		free(cur);
		cur = next;
	}
	free(phead);
}

每个人测试都不一样，所以我把全部功能实现一遍，回头你们也要学会自己实现噢！！！

test.c

#include"List.h";
void TestList1()
{
	LTNode* plist = ListInit();//初始化
	 ListPushBack(plist, 3);//尾插
	 ListPushBack(plist, 4);//尾插
	ListPushFront(plist, 2);//头插
	ListPushFront(plist, 1);//头插
	Listprint(plist);//打印
	LTNode*pos= ListFind(plist, 1);//寻找
	ListSize(plist);
	if (pos)
	{
		ListInsert(pos, 520);
	}
	Listprint(plist);
	ListEarse(pos);// 删除pos
	Listprint(plist);
	int t= ListSize(plist);//个数
	printf("%d", t);
	
	ListDestory(plist);//销毁
	plist = NULL;
}
int main()
{
	TestList1();
	return 0;
}

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总结

双向链表用c语言实现还是很简单的！！！你也赶快动手试试吧！！！

下面是我的GitHub的链接，如上代码在（顺序表_链表1.）序列，如有不明白或者问题都可以在评论区提出了噢！！！

GitHub - divertlee/opening