技術標籤：C-資料結構資料結構演算法

1.4雙向連結串列表示與實現

1、雙向連結串列是指連結串列中每個結點都有兩個指標域，一個指向後繼結點，一個指向前驅結點。prior和next.

2、雙向連結串列也分帶頭和不帶頭，帶頭操作更加方便。雙向連結串列也有迴圈結構，稱雙向迴圈連結串列。

3、帶頭雙向迴圈連結串列的判空條件為head->prior==head或head->next==head；

程式碼實現：

DLinkList.h

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

typedef int DataType;

typedef struct Node
{
	DataType data;
	struct Node* prior, * next;   //p為前指標,q為後指標
}DListNode,*DListLink;


//插入函式
int InsertDList(DListLink head,int i,DataType e)
{
	DListNode* p, * s;
	int j=0;
	p = head->next;
	while (p!=head && j<i)
	{
		p = p->next;
		j++;
	}
	if (j!=i)
	{
		printf("插入位置不正確");
		return 0;
	}
	s = (DListNode *)malloc(sizeof(DListNode));
	if (s==NULL)
	{
		return -1;
	}
	s->data = e;
	s->prior = p->prior;
	p->prior->next = s;
	s->next = p;
	p->prior = s;
	return 1;
}

//刪除函式
int DeleteDList(DListLink head, int i, DataType *e)
{
	DListNode* p, * s;
	int j = 0;
	p = head->next;
	while (p != head && j < i)
	{
		p = p->next;
		j++;
	}
	if (j != i)
	{
		printf("輸入位置不正確");
		return 0;
	}
	p->prior->next = p->next;
	p->next->prior = p->prior;
	free(p);
	return 1;
}

//初始化函式
int InitDList(DListLink *head)
{
	*head = (DListLink)malloc(sizeof(DListNode));
	if (!head)
		return -1;
	(*head)->next = *head;
	(*head)->prior = *head;
	return 1;
}

//建立迴圈單鏈表
int CreateDList(DListLink head,int n)
{
	DListNode* s, * q;
	DataType e;
	q = head;
	for (int i = 1; i <= n; i++)
	{
		printf("請輸入第%d個元素:",i);
		e = getchar();
		s = (DListNode *)malloc(sizeof(DListNode));
		s->data = e;
		s->next = q->next;
		q->next = s;
		s->prior = q;
		head->prior = s;
		q = s;
		getchar();
	}
	return 1;
}

//輸出函式
void PrintDList(DListLink head)
{
	DListNode* p;
	p = head->next;
	while (p!=head)
	{
		printf("%c",p->data);
		p = p->next;
	}
	printf("\n");
}
 

test.c

#include <stdio.h>
#include <stdlib.h>
#include "DLinkList.h"

void main()
{
	DListLink h;
	int n;
	int pos;
	char e;
	InitDList(&h);
	printf("輸入元素的個數:");
	scanf_s("%d",&n);
	getchar();
	CreateDList(h, n);
	printf("連結串列中的元素:");
	PrintDList(h);
	printf("請輸入插入的元素:");
	scanf_s("%c",&e);
	getchar();
	printf("請輸入插入元素的位置:");
	scanf_s("%d", &pos);
	InsertDList(h, pos, e);
	printf("插入後連結串列中的元素:");
	PrintDList(h);
}