循环双链表的操作

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CDLinkList.h

#pragma once
#include<stdio.h>
#include<malloc.h>

typedef int DataType;

typedef struct CDLNode
{
	DataType data;
	struct CDLNode* prior;
	struct CDLNode* next;
}CDLNode,*CDLinkList;

void InitCDLinkList(CDLinkList* head);

int InsertElem(CDLinkList head, int i, DataType e);

int DeleteElem(CDLinkList head, int i, DataType* e);

void InsertElemR(CDLinkList head, DataType e);

void InsertElemF(CDLinkList head, DataType e);

CDLinkList.cpp

#define _CRT_SECURE_NO_WARNINGS 1
#include"CDLinkList.h"

void InitCDLinkList(CDLinkList* head)
{
	(*head) = (CDLinkList)malloc(sizeof(CDLNode));
	(*head)->prior = (*head);
	(*head)->next = (*head);
}

int InsertElem(CDLinkList head, int i, DataType e)
{
	CDLNode* pre, * p;
	int j;
	if (i <= 0)
	{
		printf("插入位置错误！\n");
		return -1;
	}
	pre = head;
	j = 0;
	while (pre->next != head && j<i-1)
	{
		pre = pre->next;
		j++;
	}
	if (j != i - 1)
	{
		printf("插入位置错误！\n");
		return 0;
	}
	p = (CDLNode*)malloc(sizeof(CDLNode));
	p->data = e;
	p->prior = pre;
	p->next = pre->next;
	pre->next->prior = p;
	pre->next = p;
	return 1;
}

int DeleteElem(CDLinkList head, int i, DataType* e)
{
	CDLNode* p;
	int j;
	if (i <= 0)
	{
		printf("删除位置错误！\n");
		return -1;
	}
	p = head;
	j = 0;
	while (p->next != head && j < i)
	{
		p = p->next;
		j++;
	}
	if (j != i)
	{
		printf("删除位置错误！\n");
		return 0;
	}
	p->prior->next = p->next;
	p->next->prior = p->prior;
	*e = p->data; 
	free(p);
	return 1;
}

void InsertElemR(CDLinkList head, DataType e)
{
	CDLNode* pre, * p;
	pre = head;
	while (pre->next != head)
	{
		pre = pre->next;
	}
	p = (CDLNode*)malloc(sizeof(CDLNode));
	p->data = e;
	p->prior = pre;
	p->next = head;
	head->prior = p;
	pre->next = p;
}

void InsertElemF(CDLinkList head, DataType e)
{
	CDLNode* p;
	p = (CDLNode*)malloc(sizeof(CDLNode));
	p->data = e;
	p->prior = head;
	p->next = head->next;
	head->next->prior = p;
	head->next = p;
}