数据结构 | C语言实现带头双向循环链表

1.Data.h

#pragma once
#include
#include
#include
typedef int LTDataType;
typedef struct LTListNode
{
	struct LTListNode* prev;
	struct LTListNode* next;
	LTDataType x;
}LTNode;

LTNode* LTInit();
void LTPushBack(LTNode* phead, LTDataType x);
void LTPushFront(LTNode* phead, LTDataType x);
void LTPopBack(LTNode* phead);
void LTPopFront(LTNode* phead);


void LTInsert(LTNode* pos, LTDataType x);
void LTErases(LTNode* pos);

void LTPrint(LTNode* phead);

//如果我们需要快速完成一个链表，只需要写好LTInsert，头插和尾插都可以复用
//同理，只需要写好LTErase，头删尾删都可以完成
// 双向链表销毁
void LTDestory(LTNode* phead);

2.main.cpp

#include"Data.h"

int main()
{
	LTNode* phead = LTInit();
	LTPushBack(phead, 213);
	LTPushBack(phead, -23);
	LTPushBack(phead, 2);
	LTPushFront(phead, 23);
	LTPushBack(phead, 123);
	
	LTPrint(phead);
	LTPopBack(phead);
	LTPrint(phead);
	LTErases(phead->next->next);
	LTPrint(phead);
	return 0;
}

3.Data.cpp

#include"Data.h"

LTNode* LTInit()
{
	LTListNode* newnode = (LTNode*)malloc(sizeof(LTNode));
	newnode->next = newnode;
	newnode->prev = newnode;
	newnode->x = 0;
	return newnode;
}

void LTInsert(LTNode* pos, LTDataType x)
{
	assert(pos);
	LTNode* newnode = LTInit();
	newnode->x = x;
	LTNode* posnext = pos->next;
	pos->next = newnode;
	newnode->next = posnext;
	newnode->prev = pos;
	posnext->prev = newnode;
}

void LTPushBack(LTNode* phead, LTDataType x)
{
	LTInsert(phead->prev, x);
}

void LTPushFront(LTNode* phead, LTDataType x)
{
	LTInsert(phead, x);
}

void LTPopFront(LTNode* phead)
{
	assert(phead);
	/*if (phead->next == phead)
		return;
	else if (phead->next->next == phead)
	{
		free(phead->next);
		phead->prev = phead;
		phead->next = phead;
	}
	else
	{
		LTNode* next = phead->next->next;
		free(phead->next);
		phead->next = next;
		next->prev = phead;
	}*/
	LTErases(phead->next);
}

void LTPopBack(LTNode* phead)
{
	assert(phead);
	/*if (phead->next == phead)
	{
		return;
	}
	else if (phead->next->next==phead)
	{
		free(phead->next);
		phead->next = phead;
		phead->prev = phead;
	}
	else
	{
		LTNode* tail = phead->prev;
		LTNode* tailprev = tail->prev;
		free(tail);
		tailprev->next = phead;
		phead->prev = tailprev;
	}*/
	LTErases(phead->prev);
}

void LTErases(LTNode* pos)
{
	assert(pos);
	LTNode* posnext = pos->next;
	LTNode* posprev = pos->prev;
	free(pos);
	posnext->prev = posprev;
	posprev->next = posnext;
}

void LTPrint(LTNode* phead)
{
	assert(phead);
	LTNode* cur = phead->next;
	printf("head<=>");
	while (cur!=phead)
	{
		printf("%d<=>", cur->x);
		cur = cur->next;
	}
	printf("head\n");
	printf("\n");
}