[数据结构]——带有头节点的双向循环链表（创建头节点创建新节点头插尾插头删尾删删除pos位的结点在pos位前插入结点查找销毁）

Posted 2022-11-05 FortunateJA

List.h

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

typedef int ListDataType;

typedef struct ListNode

	struct ListNode *next;
	struct ListNode *prev;
	ListDataType data;
ListNode;

ListNode* ListInit(); //创建头结点
ListNode* BuyListNode(ListDataType x); //创建新结点
void ListPrint(ListNode *phead); //打印链表
void ListDestory(ListNode *phead); //销毁链表

void ListPushFront1(ListNode *phead, ListDataType x); //头插
void ListPushFront2(ListNode *phead, ListDataType x); //利用ListInsert函数实现
void ListPushBack(ListNode *phead, ListDataType x);	//尾插
void ListPopFront(ListNode *phead); //头删
void ListPopBack1(ListNode *phead); //尾删
void ListPopBack2(ListNode *phead); //利用ListErase函数实现

void ListInsert(ListNode *pos, ListDataType x); //在pos位的前一个插入
void ListErase(ListNode *pos); //删除pos位的结点
ListNode* Find(ListNode *phead, ListDataType x); //查找

List.c

#include "List.h"

ListNode* ListInit() //创建头结点

	ListNode *phead = (ListNode *)malloc(sizeof(ListNode));
	if (phead == NULL)
	
		printf("malloc fail\\n");
		exit(-1);
	
	phead->next = phead;
	phead->prev = phead;
	return phead;
 

ListNode* BuyListNode(ListDataType x) //创建新结点

	ListNode *newnode = (ListNode *)malloc(sizeof(ListNode));
	if (newnode == NULL)
	
		printf("malloc fail\\n");
		exit(-1);
	
	newnode->data = x;
	newnode->next = NULL;
	newnode->prev = NULL;


void ListPrint(ListNode *phead) //打印链表

	assert(phead);
	ListNode *tmp = phead->next;
	while (tmp != phead)
	
		printf("%d ", tmp->data);
		tmp = tmp->next;
	
	printf("\\n");


void ListDestory(ListNode *phead) //销毁链表

	ListNode *tmp = phead->next;
	while (tmp != phead)
	
		ListNode *tmpNext = tmp->next;
		ListErase(tmp);
		tmp = tmpNext;
	
	free(phead);
	phead = NULL;


void ListPushFront1(ListNode *phead, ListDataType x) //头插

	assert(phead);
	ListNode *newnode = BuyListNode(x);
	ListNode *pheadNext = phead->next;
	phead->next = newnode;
	newnode->prev = phead;
	newnode->next = pheadNext;
	pheadNext->prev = newnode;


void ListPushFront2(ListNode *phead, ListDataType x)

	ListInsert(phead->next, x);


void ListPushBack(ListNode *phead, ListDataType x)	//尾插

	assert(phead);
	ListNode *newnode = BuyListNode(x);
	ListNode *tmp = phead->prev;
	tmp->next = newnode;
	newnode->prev = tmp;
	phead->prev = newnode;
	newnode->next = phead;	


void ListPopFront(ListNode *phead) //头删（要考虑链表中没有数据了只存在头节点的情况）

	assert(phead);
	assert(phead->next != phead);

	ListNode *tmp = phead->next;
	ListNode *tmpNext = tmp->next;
	phead->next = tmpNext;
	tmpNext->prev = phead;
	free(tmp);
	//tmp = NULL;	 


void ListPopBack1(ListNode *phead) //尾删（要考虑链表中没有数据了只存在头节点的情况）

	assert(phead);
	assert(phead->next != phead);

	ListNode *tmp = phead->prev;
	ListNode *tmpPrev = tmp->prev;
	phead->prev = tmpPrev;
	tmpPrev->next = phead;
	free(tmp);


void ListPopBack2(ListNode *phead)

	ListErase(phead->prev);


void ListInsert(ListNode *pos, ListDataType x) //在pos位的前一个插入

	assert(pos);
	ListNode *newnode = BuyListNode(x);
	ListNode *posPrev = pos->prev;
	posPrev->next = newnode;
	newnode->prev = posPrev;
	newnode->next = pos;
	pos->prev = newnode;


void ListErase(ListNode *pos) //删除pos位的结点（pos位不能是phead）

	assert(pos);
	ListNode *posNext = pos->next;
	ListNode *posPrev = pos->prev;
	posPrev->next = posNext;
	posNext->prev = posPrev;
	free(pos);


ListNode* Find(ListNode *phead, ListDataType x) //查找

	assert(phead);
	ListNode *tmp = phead->next;
	while (tmp != phead)
	
		if (tmp->data == x)
		
			return tmp;
		
		tmp = tmp->next;
	

Test.c

#include "List.h"

int main()

	ListNode *L = ListInit();

	ListPushFront1(L, 1);
	ListPushFront1(L, 2);
	ListPushFront1(L, 3);
	printf("PushFront1:");
	ListPrint(L);

	ListPushBack(L, 4);
	ListPushBack(L, 5);
	ListPushBack(L, 6);
	printf("PushBack:");
	ListPrint(L);

	ListPopFront(L);
	ListPopFront(L);
	printf("PopFront:");
	ListPrint(L);

	ListPopBack1(L);
	ListPopBack1(L);
	printf("PopBack1:");
	ListPrint(L);

	ListPushFront2(L, 10);
	printf("PushFront2:");
	ListPrint(L);

	ListPopBack2(L);
	printf("PopBack2:");
	ListPrint(L);

	ListNode *tmp=Find(L, 10);
	tmp->data = 20;
	printf("After change:");
	ListPrint(L);

	ListDestory(L);
	printf("After destory:");
	printf("\\n");
	ListPrint(L);

	return 0;

测试结果