带头循环双向链表

lish.h

#pragma once
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
typedef int LTDateType;

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

LTNode* ListInit();
void ListPrint(LTNode* phead);
LTNode* BuyListNode(LTDateType x);

void ListPushBack(LTNode* phead, LTDateType x);
void ListPopBack(LTNode* phead);
void ListPushFront(LTNode* phead, LTDateType x);
void ListPopFront(LTNode* phead);

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

void ListInsert(LTNode* pos, LTDateType x);
void ListErase(LTNode* pos);

void ListDestory(LTNode* phead);

list.c

#define _CRT_SECURE_NO_WARNINGS 1
#include "list.h"

LTNode* ListInit()
{
	LTNode* phead = (LTNode*)malloc(sizeof(LTNode));
	phead->next = phead;
	phead->prev = phead;
	return phead;
}

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

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

void ListPushBack(LTNode* phead, LTDateType x)
{
	LTNode* newnode = BuyListNode(x);
	LTNode* tail = phead->prev;
	tail->next = newnode;
	newnode->prev = tail;
	newnode->next = phead;
	phead->prev = newnode;
}

void ListPopBack(LTNode* phead)
{
	assert(phead);
	assert(phead->next != phead);
	LTNode* tail = phead->prev;
	LTNode* tailPrev = tail->prev;
	phead->prev = tailPrev;
	tailPrev->next = phead;
	free(tail);
}


void ListPushFront(LTNode* phead, LTDateType x)
{
	LTNode* newnode = BuyListNode(x);
	LTNode* next = phead->next;

	phead->next = newnode;
	newnode->prev = phead;

	newnode->next = next;
	next->prev = newnode;
}

void ListPopFront(LTNode* phead)
{
	assert(phead);
	assert(phead->next != phead);
	LTNode* next = phead->next;
	phead->next = next->next;
	next->next->prev = phead;
	free(next);
}
LTNode* ListFind(LTNode* phead, LTDateType x)
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		if (x == cur->data)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}

void ListInsert(LTNode* pos, LTDateType x)
{
	LTNode* newnode = BuyListNode(x);
	LTNode* Prev = pos->prev;
	Prev->next = newnode;
	newnode->prev = Prev;
	newnode->next = pos;
	pos->prev = newnode;
}

void ListErase(LTNode* pos)
{
	LTNode* posPrev = pos->prev;
	LTNode* posNext = pos->next;
	posPrev->next = posNext;
	posNext->prev = posPrev;
	free(pos);
}
void ListDestory(LTNode* phead)
{
	assert(phead);
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		LTNode* next = cur->next;
		free(cur);
		cur = next;
	}
	free(phead);
	phead = NULL;
}

test.c

#define _CRT_SECURE_NO_WARNINGS 1
#include "list.h"

void test()
{
	LTNode* plist = ListInit();
	//ListPushBack(plist, 1);
	//ListPushBack(plist, 2);
	//ListPushBack(plist, 3);
	//ListPushBack(plist, 4);
	//ListPrint(plist);
	//ListPopBack(plist);
	//ListPopBack(plist);
	//ListPopBack(plist);
	//ListPopBack(plist);
	//ListPrint(plist);
	ListPushFront(plist, 1);
	ListPushFront(plist, 2);
	ListPushFront(plist, 3);
	ListPushFront(plist, 4);
	ListPrint(plist);
	//printf("%d", (ListFind(plist, 2))->data);
	ListInsert(ListFind(plist, 2), 9);
	ListPrint(plist);
	ListErase(ListFind(plist, 9));
	ListPrint(plist);


}

int main()
{
	test();
	return 0;
}