实现双向链表的增删改查

使用双向链表实现：定义双向链表中节点的结构，头删，尾删，查找，头插，尾插，在pos位置之后插入数据，删除pos位置的数据，删除数据。

在ListNode.h中写出所需函数和定义双向链表中节点的结构。

在ListNode.c中定义各种函数。

在main.c中对函数进行测试。

ListNode.h

#pragma once
#define  _CRT_SECURE_NO_WARNINGS
#include
#include
#include

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


LTNode* LTInit();
void LTDestroy(LTNode* phead);
void LTPrint(LTNode* phead);


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

void LTPushFront(LTNode* phead, LTDataType x);
void LTPopFront(LTNode* phead);
//在pos位置之后插入数据
void LTInsert(LTNode* pos, LTDataType x);
void LTErase(LTNode* pos);
LTNode* LTFind(LTNode* phead, LTDataType x);

ListNode.c

#include"ListNode.h"

LTNode* NewNode(LTDataType val)
{
	LTNode* pnew = (LTNode*)malloc(sizeof(LTNode));
	if (pnew == NULL) {
		perror("malloc fail!");
		exit(1);
	}
	pnew->data = val;
	pnew->next = pnew->prev = pnew;
	return pnew;
}

LTNode* LTInit()
{
	LTNode* head = NewNode(-1);
	return head;
}
void LTDestroy(LTNode* phead)
{
	assert(phead);
	LTNode* pcur = phead->next;
	while (pcur != phead)
	{
		LTNode* next = pcur->next;
		free(pcur);
		pcur = next;
	}
	free(phead);
	phead = NULL;

}
void LTPrint(LTNode* phead)
{
	LTNode* pcur = phead->next;
	while (pcur != phead)
	{
		printf("%d->", pcur->data);
		pcur = pcur->next;
	}
}
void LTPushBack(LTNode* phead, LTDataType x)
{
	assert(phead);
	LTNode* pnew = NewNode(x);
	pnew->next = phead;
	pnew->prev = phead->prev;
	phead->prev->next = pnew;
	phead->prev = pnew;

}
void LTPopBack(LTNode* phead)
{
	assert(phead);
	assert(phead->next != phead);
	LTNode* del = phead->prev;
	phead->prev->prev->next = phead;
	phead->prev = phead->prev->prev;
	free(del);
	del = NULL;
}

void LTPushFront(LTNode* phead, LTDataType x)
{
	assert(phead);
	LTNode* pnew = NewNode(x);
	pnew->next = phead->next;
	pnew->prev = phead;
	phead->next->prev = pnew;
	phead->next = pnew;
}
void LTPopFront(LTNode* phead)
{
	assert(phead);
	assert(phead->next!=phead);
	LTNode* tmp = phead->next;
	phead->next->next->prev = phead;
	phead->next = phead->next->next;
	free(tmp);
	tmp = NULL;
}
//在pos位置之后插入数据
void LTInsert(LTNode* pos, LTDataType x)
{
	LTNode* pnew = NewNode(x);
	pnew->next = pos->next;
	pnew->prev = pos;
	pos->next->prev = pnew;
	pos->next = pnew;
}
void LTErase(LTNode* pos)
{
	LTNode* tmp = pos;
	pos->prev->next = pos->next;
	pos->next->prev = pos->prev;
	free(tmp);
	tmp = NULL;
}
LTNode* LTFind(LTNode* phead, LTDataType x)
{
	assert(phead);
	assert(phead->next!=phead);

	LTNode* pcur = phead->next;
	while (pcur != phead)
	{
		if (pcur->data == x)
		{
			return pcur;
		}
		pcur = pcur->next;
	}
	return NULL;
}

main.c

#include"ListNode.h"

int main()
{
	LTNode* head = LTInit();
	LTPushBack(head, 2);
	LTPushBack(head, 5);
	LTPushBack(head, 9);
	LTPushBack(head, 3);
	LTPushFront(head, 10);
	LTPushFront(head, 18);
	LTPushFront(head, 11);
	LTErase(LTFind(head, 18));
	LTInsert(LTFind(head, 10), 55);
	LTPrint(head);
	LTDestroy(head);

	return 0;
}

运行结果：