数据结构——双向链表

头文件

#ifndef __DOULIST_H__
#define __DOULIST_H__

#include
#include

/*存放数据类型*/
typedef int DataType;

/*存放节点类型*/
typedef struct node
{
    DataType Data;                 //数据
    struct node *pPre;          //前一个节点指针
    struct node *pNext;         //后一个节点指针
}LinkNode;

#endif

创建双向链表

LinkNode *CreateDouList(void)
{
    LinkNode *pTmpNode = NULL;

    pTmpNode = malloc(sizeof(LinkNode));
    if(NULL == pTmpNode)
    {
        return NULL;
    }

    pTmpNode->pPre = pTmpNode->pNext = NULL;

    return pTmpNode;
}

插入链表

• 头插法

/*插入链表——头插法*/
int HeadInsertDouList(LinkNode *pHead,DataType TmpData)
{
    LinkNode *pTmpNode = NULL;

    pTmpNode = malloc(sizeof(LinkNode));
    if(NULL == pTmpNode)
    {
        return -1;
    }    

    pTmpNode->Data = TmpData;
    pTmpNode->pNext = pHead->pNext;
    pTmpNode->pPre = pHead;
    pHead->pNext = pTmpNode;
    if(pTmpNode->pNext != NULL)
    {
        pTmpNode->pNext->pPre = pTmpNode;
    }

    return 0;
}

• 尾插法

/*插入链表——尾插法*/
int TailInsertDouList(LinkNode *pHead,DataType TmpData)
{
    LinkNode *pTmpNode = NULL;
    LinkNode *pNewNode =NULL;

    pNewNode = pHead;
    if(pNewNode->pNext != NULL)
    {
        pNewNode = pNewNode->pNext;
    }

    pTmpNode = malloc(sizeof(LinkNode));
    if(NULL == pTmpNode)
    {
        return -1;
    }    

    pTmpNode->Data = TmpData;
    pTmpNode->pNext = NULL;
    pTmpNode->pPre = pNewNode;
    pNewNode->pNext = pTmpNode;

    return 0;
}

遍历打印双向链表

• 正向

/*遍历打印双向链表——正向*/
int FrontShowDouList(LinkNode *pHead)
{
    LinkNode *pTmpNode = NULL;

    pTmpNode = pHead->pNext;
    if(NULL == pTmpNode)
    {
        return -1;
    }   
    //遍历
    while(pTmpNode != NULL)
    {
            printf("%d  \n",pTmpNode->Data);       //打印
            pTmpNode = pTmpNode->pNext;
    }
    printf("\n");
    return 0;
}

• 反向

/*遍历打印双向链表——反向*/
int BehindShowDouList(LinkNode *pHead)
{
    LinkNode *pTmpNode = NULL;
    //遍历
    pTmpNode = pHead;
    while(pTmpNode->pNext != NULL)
    {
        pTmpNode = pTmpNode->pNext;         //指针遍历到末尾
    }
    
    while(pTmpNode != pHead)
    {
            printf("%d  \n",pTmpNode->Data);       //打印
            pTmpNode = pTmpNode->pPre;             //指针向前一节点遍历
    }
    printf("\n");
    return 0;
}

删除链表节点

/*删除双向链表节点*/
int DeleteDouList(LinkNode *pHead, DataType TmpData)
{
    LinkNode *pTmpNode = NULL;
    LinkNode *pNextNode = NULL;
    int cnt = 0;

    pTmpNode = pHead->pNext;
    while(pTmpNode->Data)
    {
        if(pTmpNode->Data == TmpData)
        {
            pNextNode = pTmpNode->pNext;
            pTmpNode->pPre->pNext = pNextNode;
            if(pTmpNode->pNext !=NULL)
            {
                pTmpNode->pNext->pPre = pTmpNode->pPre;
            }
            free(pTmpNode);
            pTmpNode = pNextNode;
            cnt++;
        }
        else
        {
            pTmpNode = pTmpNode->pNext;
        }
    }

    return cnt;
}

销毁链表

/*销毁双向链表*/
int DestroyDouList(LinkNode **ppHead)
{
    LinkNode *pTmpNode = NULL;
    LinkNode *pFreeNode = NULL;

    pTmpNode = *ppHead;
    pFreeNode = *ppHead;
    
    while (pTmpNode != NULL)
    {
        pTmpNode = pTmpNode->pNext;
        free(pFreeNode);
        pFreeNode = pTmpNode;
    }
    *ppHead = NULL;

    return 0;
}