数据结构----双向链表

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_41026740/article/details/83387696

DoubleList.h

#ifndef __DOUBLELIST_H
#define __DOUBLELIST_H

#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<malloc.h>

typedef int ElemType;

//定义每一个结点的结构
typedef struct Node
{
	struct Node *prev; //结点的前驱
	ElemType data;     //结点的数据域
	struct Node *next; //结点的后继	
}Node;

//定义双向链表结构
typedef struct Doublelist
{
	Node head;  //头结点
	int count;  //结点数目
}Doublelist, *pDoulist;

void InitDoublelist(pDoulist list); 
   
void InsertDoublelist(pDoulist list, ElemType val , int pos);

void  InsertHeadDoublelist (pDoulist list,ElemType val);

void InsertTailDoublelist(pDoulist list,ElemType val);

void DeleteDoublelist(pDoulist list,int pos);

void DeleteHeadDoublelist(pDoulist list);

void DeleteTailDoublelist(pDoulist list);

void DestroyDoublelist(pDoulist list);//销毁

void Show1(pDoulist list); //打印输出
void Show2(pDoulist list);

void Reverseshow(pDoulist list); //逆序输出

#endif

DoubleList.c

#include"DoubleList.h"

//初始化双向链表
void InitDoublelist(pDoulist list)
{
	assert(list != NULL);

	list->head.next  = NULL;   //尾指针
	list->head.prev  = NULL;   //头指针
	list->count = 0;           //结点个数

}

//在双向链表中插入一个结点
/*1：先考虑普通情况下的结点插入
void InsertDoublelist(pDoulist list, ElemType val, int pos)
{
	assert(list != NULL);
	if( pos < 0 | pos > list->count )
	{
		printf("pos is error\n");
		return ;
	}
	Node *p = &list->head;
	Node *s = ( Node *)malloc(sizeof(Node));
	while( pos > 0)
	{
		p = p->next;
		pos--;
	}
	s->data = val;
	if( p->next != NULL)
	{
		p->next->prev = s;
	}
	s->next = p->next;
	s->prev = p;
	p->next = s;
	list->count++;
}
*/
	//2：考虑特殊情况的结点插入优化代码（list->count == 0  和 pos == list->count ）
static Node *BuyNode(ElemType val, Node *prev, Node *next )//创建结点
{
	Node *s = (Node *)malloc(sizeof(Node));
	assert( s != NULL);

	s->data = val;
	s->prev = prev;
	s->next = next;

	return s;
}
void InsertDoublelist(pDoulist list, ElemType val, int pos)
{
	assert( list != NULL);
	if( (pos < 0) || (pos > list->count))
	{
		printf("pos is error\n");
		return ;
	}
	Node *p = &list->head;
	while( pos > 0)
	{
		p = p->next;
		pos --;
	}
	Node *s = BuyNode( val, p, p->next);//插入结点
	if( p->next != NULL)//考虑尾插
	{
		p->next->prev = s;
	}
	p->next = s;
	list->count++;
}

void  InsertHeadDoublelist (pDoulist list,ElemType val)
{
	InsertDoublelist(list, val, 0);
}

void InsertTailDoublelist(pDoulist list,ElemType val)
{
	InsertDoublelist(list, val, list->count);
}

void DeleteDoublelist(pDoulist list,int pos)
{
	assert(list != NULL);
	if((pos < 1) ||(pos > list->count))
	{
		printf("pos is error\n");
		return ;
	}
	Node * p = &list->head;
	while( pos > 0)
	{
		p = p->next;
		pos --;
	}
	p->prev->next = p->next;
	if ( p->next != NULL)
	{
		p->next->prev = p->prev;
	}
	free(p);
	list->count--;
}

void DeleteHeadDoublelist(pDoulist list)
{
	DeleteDoublelist(list,1);
}

void DeleteTailDoublelist(pDoulist list)
{
	DeleteDoublelist(list,list->count);
}

void Show1(pDoulist list)
{
	assert(list != NULL);
	Node *p = list->head.next;
	while( p != NULL)//用指针遍历整个链表，指针跑一个输出一个
	{
		printf("%3d",p->data);
		p = p->next;
	}
	printf("\n");
}

void Show2(pDoulist list)
{
	assert( list != NULL);
	Node *p = list->head.next;
	int tmp = list->count;
	while( tmp > 0)
	{
		printf("%3d",p->data);
		p = p->next;
		tmp --;
	}
	printf("\n");	
}

//逆序输出双向链表中的数据
void Reverseshow(pDoulist list)
{
	assert( list != NULL);
	Node *p = &list->head;
	while( p->next != NULL)//先让指针跑到最后一个结点
	{
		p = p->next;
	}
	while( p->prev != NULL)//指针开始往前跑，指针跑一个输出一个
	{
		printf("%3d",p->data);
		p = p->prev;
	}
	printf("\n");
}

void DestroyDoublelist(pDoulist list)
{
	assert(list != NULL);
	while( list->count > 0)
	{
		DeleteHeadDoublelist(list);
	}
}

main.c

#include"DoubleList.h"

int main()
{
	Doublelist list;
	Doublelist *p = &list;
	InitDoublelist(&list); //初始化

	printf("count3 =  %d\n",p->count);
	for( int i = 0; i < 5; i++ )
	{
		InsertDoublelist(&list,i * 10 ,i);  //插入结点
		Show1(&list);
	}
	Show1(&list);

	InsertTailDoublelist(&list,88);
	InsertHeadDoublelist (&list,99);
	Show2(&list);
	Reverseshow(&list);//逆序输出

	for( int i = 4; i > 0; i--)
	{
		DeleteDoublelist(&list,i);//删除结点
		Show2(&list);
	}
	Show2(&list);
	return 0;
}