双向链表的实现

List.h

#pragma once

#include<stdio.h>
#include<stdlib.h>
#include<assert.h>

typedef int LTDataType;

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

ListNode* ListInit();

void ListPrint(ListNode* phead);

void ListDestroy(ListNode* phead);

void ListPushBack(ListNode* phead, LTDataType x);


void ListPushFront(ListNode* phead, LTDataType x);

void ListPopFront(ListNode* phead);

void ListPopBack(ListNode* phead);

ListNode* ListFind(ListNode* phead, LTDataType x);

//pos位置之前插入x
void ListInsert(ListNode* pos, LTDataType x);

//删除pos位置的值
void ListErase(ListNode* pos);

List.c

#include"List.h"

ListNode* BuyListNode(LTDataType x)
{
	ListNode* newnode = (ListNode*)malloc(sizeof(ListNode));
	newnode->data = x;
	newnode->next = NULL;
	newnode->prev = NULL;
	return newnode;
}
ListNode* ListInit()
{
	ListNode* phead = BuyListNode(0);
	phead->next = phead;
	phead->prev = phead;

	return phead;
}
void ListPrint(ListNode* phead)
{
	assert(phead);
	ListNode* cur = phead->next;
	while (cur != phead)
	{
		printf("%d ", cur->data);
		cur = cur->next;
	}
	printf("\n");
}
void ListDestroy(ListNode* phead)
{
	assert(phead);
	ListNode* cur = phead->next;
	while (cur != phead)
	{
		ListNode* next = cur->next;
		free(cur);
		cur = next;
	}
	free(phead);
	phead = NULL;
}
void ListPushBack(ListNode* phead, LTDataType x)
{
	/*assert(phead);
	ListNode* tail = phead->prev;
	ListNode* newnode = BuyListNode(x);
	tail->next = newnode;
	newnode->prev = tail;
	newnode->next = phead;
	phead->prev = newnode;*/
	ListInsert(phead->prev, x);
}

void ListPushFront(ListNode* phead, LTDataType x)
{
	/*assert(phead);
	ListNode* first = phead->next;
	ListNode* newnode = BuyListNode(x);
	phead->next = newnode;
	newnode->prev = phead;
	newnode->next = first;
	first->prev = newnode;*/
	ListInsert(phead->next, x);
}
void ListPopFront(ListNode* phead)
{
	/*assert(phead);
	assert(phead->next != phead);
	ListNode* first = phead->next;
	ListNode* second = first->next;
	phead->next = second;
	second->prev = phead;
	free(first);
	first = NULL;*/
	ListErase(phead->next);
}
void ListPopBack(ListNode* phead)
{
	/*assert(phead);
	assert(phead->next != phead);
	ListNode* tail = phead->prev;
	ListNode* prev = tail->prev;
	prev->next = phead;
	phead->prev = prev;
	free(tail);
	tail = NULL;*/
	ListErase(phead->prev);
}

ListNode* ListFind(ListNode* phead, LTDataType x)
{
	assert(phead);
	ListNode* cur = phead->next;
	while (cur != phead)
	{
		if (cur->data == x)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

//pos位置之前插入x
void ListInsert(ListNode* pos, LTDataType x)
{
	assert(pos);
	ListNode* prev = pos->prev;
	ListNode* newnode = BuyListNode(x);
	prev->next = newnode;
	newnode->prev = prev;
	newnode->next = pos;
	pos->prev = newnode;
}

//删除pos位置的值
void ListErase(ListNode* pos)
{
	assert(pos);
	ListNode* prev = pos->prev;
	ListNode* next = pos->next;
	prev->next = next;
	next->prev = prev;
	free(pos);
	pos = NULL;
}

test.c

#define _CRT_SECURE_NO_WARNINGS 1
#include"List.h"
void TestList1()
{
	ListNode* plist = ListInit();
	ListPushBack(plist, 1);
	ListPushBack(plist, 2);
	ListPushBack(plist, 3);
	ListPushBack(plist, 4);
	ListPrint(plist);
	ListPushFront(plist, 0);
	ListPrint(plist);
	ListPopFront(plist);
	ListPrint(plist);
	ListPopBack(plist);
	ListPrint(plist);
	ListDestroy(plist);

}
void TestList2()
{
	ListNode* plist = ListInit();
	ListPushBack(plist, 1);
	ListPushBack(plist, 2);
	ListPushBack(plist, 3);
	ListPushBack(plist, 4);
	ListPrint(plist);
	ListNode* pos = ListFind(plist, 3);
	if (pos)
	{
		pos->data *= 10;
		printf("找到了,并且节点位置的值乘以10\n");
		ListPrint(plist);

	}
	else
	{
		printf("没有找到\n");
	}
	ListInsert(pos, 300);
	ListPrint(plist);
	ListErase(pos);
	ListPrint(plist);
	ListDestroy(plist);

}
int main()
{
	//TestList1();
	TestList2();
	return 0;
}