双向链表的简单操作

#ifndef _DATA_H_
#define _DATA_H_

typedef struct DbNode
{
int data;
struct DbNode *left;
struct DbNode *right;
}DbNode;
#endif

#ifndef DOUBLE_LINKLIST_H
#define DOUBLE_LINKLIST_H
#include "data.h"
#include <stdlib.h>
#include <stdio.h>

DbNode* CreateNode(int data)
{
DbNode *pnode = (DbNode*)malloc(sizeof(DbNode));
pnode->data = data;
pnode->left	= pnode->right = NULL;
#ifdef DEBUG
printf("%s data = %d\n",__FUNCTION__,data);
#endif
return pnode;
}

DbNode* CreateList(int head)
{
DbNode *pnode = (DbNode*)malloc(sizeof(DbNode));
pnode->data = head;
pnode->left	= pnode->right = NULL;
#ifdef DEBUG
printf("%s head = %d\n",__FUNCTION__,head);
#endif
return pnode;
}

DbNode* AppendNode(DbNode* head,int data)
{
DbNode* node = CreateNode(data);
DbNode* p = head;
DbNode* q;

while(p != NULL)
{
q = p;
p = p->right;
}

q->right = node;
node->left = q;

#ifdef DEBUG
printf("%s data = %d\n",__FUNCTION__,data);
#endif
return head;
}

int GetLength(DbNode* head)
{
int count = 1;
DbNode* pnode = NULL;

if(head == NULL)
return 0;

pnode = head->right;

while(pnode != NULL)
{
pnode = pnode->right;
count++;
}

return count;
}

void PrintList(DbNode* head)
{
DbNode* pnode = NULL;

if(head == NULL)
return;

pnode = head;
printf("Double list show as below\n");
while(pnode != NULL)
{
printf("%d ",pnode->data);
pnode = pnode->right;
}
printf("\n");
}

int FindNode(DbNode* head,int find_this_data)
{
int pos = 0;
DbNode* pnode = head;
if(head == NULL)
return -1;

while(pnode->right != NULL && pnode->data != find_this_data)
{
pnode = pnode->right;
pos++;
}
/*
* There is no this specific number
* */
if(pnode->right == NULL && pnode->data != find_this_data)
return -2;

return pos + 1;
}

DbNode* FindNode2(DbNode* head,int data)
{
DbNode* pnode = head;
/*
* 链表为空
* */
if(head == NULL)
return NULL;
/*
* 找到数据或者到达链表尾部就退出while循环
* */
while(pnode->right != NULL && pnode->data != data)
pnode = pnode->right;
/*
* 没有找到数据为data的结点
* */
if(pnode->right == NULL && pnode->data != data)
return NULL;

return pnode;
}

void InsertNode(DbNode* head,int insert_after_this_pos,int insert_this_data)
{
/*
* 如果头结点为空，什么都不操作
* */
DbNode* newNode = CreateNode(insert_this_data);
int len;
if(head == NULL)
return;
else
len = GetLength(head);

if(len < insert_after_this_pos)
{
printf("Insert out of range\n");
return;
}

DbNode* pnode = head;
int tmpPos = 0;
while(pnode->right != NULL && tmpPos < insert_after_this_pos - 1)
{
pnode = pnode->right;
tmpPos++;
}
/*
* 如果pnode是最后一个结点
* */
if(pnode->right == NULL)
{
pnode->right = newNode;
newNode->left = pnode;
}
else//是中间的结点
{
/*
* 新结点的right指向pnode结点的下一个结点
* */
newNode->right = pnode->right;
/*
* pnode的下一个结点的left指向newNode
* */
pnode->right->left = newNode;
/*
* pnode的right指向newNode
* */
pnode->right = newNode;
/*
* newNode的left指向pnode
* */
newNode->left = pnode;
}
}

DbNode* DeleteNode(DbNode* head,int del_this_data)
{
DbNode* ptmp = NULL;
DbNode* pnode = FindNode2(head,del_this_data);
/*
* 要删除的结点不存在,返回head不做任何操作
* */
if(pnode == NULL)
{
printf("There is no %d in the linklist\n",del_this_data);
return head;
}
/*
*要删除的结点是第一个结点
* */
else if(pnode->left == NULL)
{
/*
* 让第二个结点作为头结点
* */
head = pnode->right;
/*
* 链表不为空
* */
if(head != NULL)
head->left = NULL;
}
/*
*要删除的结点是最后一个结点
*让倒数第二个结点的right指向null
* */
else if(pnode->right == NULL)
pnode->left->right = NULL;
/*
* 要删除的结点是中间的结点
* */
else
{
/*
* pnode结点的上一个结点的right指向pnode的下一个结点
* */
pnode->left->right = pnode->right;
/*
* pnode的下一个结点的left指向pnode的上一个结点
* */
pnode->right->left = pnode->left;
}

free(pnode);
return head;
}
#endif

#include "doubleLinklist.h"

int main()
{
DbNode* head = CreateList(0);

int i;
for(i = 1; i < 9; i++)
head = AppendNode(head,i);

PrintList(head);
int len = GetLength(head);
printf("len(linklist) = %d\n",len);

printf("Find:");
int find;
scanf("%d",&find);
int res = FindNode(head,find);
if(res < 0)
printf("No this data\n");
else
printf("Data pos = %d\n",res);

printf("InsertPos[0,len] & data:");
int insertPos,insertData;
scanf("%d,%d",&insertPos,&insertData);

InsertNode(head,insertPos,insertData);
printf("Insert %d after pos %d\n",insertData,insertPos - 1);
PrintList(head);

int del;
printf("Delete data:");
scanf("%d",&del);
head = DeleteNode(head,del);
printf("Delete %d from linklist!!!\n",del);
PrintList(head);
return 0;
}