一个完整的双向链表程序(C语言版)

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

typedef struct tagDbNode
{
int data;
struct tagDbNode * left;
struct tagDbNode * right;
} DbNode, * pdbNode;

//创建结点
pdbNode CreateNode(int data)
{
pdbNode pnode = (pdbNode)malloc(sizeof(DbNode));
pnode->data = data;
pnode->left = pnode->right = pnode;    //创建新结点时，让其前驱和后继指针都指向自身

return pnode;
}

//=========================================================================

//创建链表
pdbNode CreateList(int head) //参数给出表头结点数据 （表头结点不作为存放有意义数据的结点）
{
pdbNode pnode = (pdbNode)malloc(sizeof(DbNode));
pnode->data = head;
pnode->left = pnode->right = pnode;

return pnode;
}

//插入新结点,总是在表尾插入; 返回表头结点
pdbNode InsertNode(pdbNode node, int data) // 参数1是链表的表头结点，参数2是要插入的结点（结点数据为data）
{
pdbNode pnode = CreateNode(data);
pdbNode ptmp = node->left;

// 从左到右恢复链接
node->left->right = pnode;
pnode->right = node;

// 从右到左恢复链接
node->left = pnode;
pnode->left = ptmp;

return node;
}

//查找结点，成功则返回满足条件的结点指针，否则返回NULL
pdbNode FindNode(pdbNode node, int data) // 参数1是链表的表头结点，参数2是要查找的结点（其中结点数据为data）
{
pdbNode pnode = node->right;
while (pnode->right != node && pnode->data != data)
{
   pnode = pnode->right;
}

if (pnode->right == node) return NULL;

return pnode;
}

//删除满足指定条件的结点, 返回表头结点, 删除失败返回NULL（失败的原因是不存在该结点）
pdbNode DeleteNode(pdbNode node, int data) // 参数1是链表的表头结点，参数2是要删除的结点（其中结点数据为data）
{
pdbNode ptmp;
pdbNode pnode = FindNode(node, data);

if (NULL == pnode) return NULL;

ptmp = pnode->left;
ptmp->right = pnode->right;
pnode->right->left = ptmp;

free(pnode);

return node;
}

//获取链表的长度
int GetLength(pdbNode node) // 参数为链表的表头结点
{
int nCount = 0;
pdbNode pnode = node->right;

while (pnode->right != node)
{
   nCount++;
}

return nCount;
}

//打印整个链表
void PrintList(pdbNode node) // 参数为链表的表头结点
{
pdbNode pnode;

if (NULL == node) return;

pnode= node->right;

while (pnode != node)
{
   printf("%d   ", pnode->data);
   pnode = pnode ->right;
}

printf("\n");
}

//将链表反序打印
void ReverPrint(pdbNode node) //参数为链表的表头结点
{
pdbNode pnode;

if (NULL == node) return;

pnode= node->left;

while (pnode != node)
{
   printf("%d   ", pnode->data);
   pnode = pnode->left;
}

printf("\n");
}

//删除链表
void DeleteList(pdbNode node) //参数为链表表头结点
{
pdbNode pnode = node->right;
pdbNode ptmp;

if (NULL == node) return;

while (pnode != node)
{
   ptmp = pnode->right;
   free(pnode);
   pnode = ptmp;
}

free(node);
}

//测试程序

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

#define FALSE 0
#define TRUE 1

typedef unsigned int bool;

void main()
{
int nChoose;
int data;
//int length;
bool bFlag = FALSE;
pdbNode pnode;
pdbNode list = CreateList(0);

while(FALSE == bFlag)
{
   printf("Main Menu\n");
   printf("1. Insert\n");
   printf("2. Delete Node\n");
   printf("3. Find\n");
   printf("4. Length\n");
   printf("5. Positive Print\n");
   printf("6. Negative Print\n");
   printf("7. Delete List\n");
   printf("0. quit\n\n");
 
   scanf("%d", &nChoose);
 
   switch(nChoose)
   {
   case 1:
    printf("Input the data to insert:");
    scanf("%d", &data);
    list = InsertNode(list, data);
    PrintList(list);
    break;
   case 2:
    printf("Input the data to delete:");
    scanf("%d", &data);
    DeleteNode(list, data);
    break;
   case 3:
    printf("Input the data to find:");
    scanf("%d", &data);
    pnode = FindNode(list, data);
  
    if (NULL != pnode)
    {
     printf("Find succeed!\n");
    }
    else
    {
     printf("Find failed!\n");
    }
    break;
   case 4:
    printf("The list's length is %d", GetLength(list));
    break;
   case 5:
    PrintList(list);
    break;
   case 6:
    ReverPrint(list);
    break;
   case 7:
    DeleteList(list);
    break;
   case 0:
    DeleteList(list);
    bFlag = TRUE;
   }
}
}