单链表（一）

我理解的单链表是一个特别简单的东西，可是教科书上给他赋予了太多的含义，使其极不易理解。这点真是很烦人。下面先说说我心中的链表，之后再学习教科书上的。虽然教科书上的东西很多都很死板，不过还是要学的拉。

 

我心中的链表

我心中的链表很是简单，就是一连串数据的链接。它相比数组的优点就在于它的形式比较灵活，插入和删除都比较方便。另外它对数据存储位置的要求比较灵活，各个数据单元存储不必是连续的。这样在数据多时，系统在内存方面处理起来也比较方便。否则系统可能就要为一大块连续的内存忙活一大阵子。好了，废话不多说，看看我心中的链表。

    这就是我心中的链表，它就是一连串数据单元的链接，从图上看不出太多与教科书上的差别，下面我们从代码上看看。我们每个数据单元为电话簿中的一个联系人。包含姓名和号码。

#define    PHB_NAME_LEN     20
#define    PHB_NUM_LEN  20

typedef struct LinkMan
{
  char name[PHB_NAME_LEN];
  char num[PHB_NUM_LEN];
  struct LinkMan *next;
}LinkMan,*pLinkMan;

int GetPhbLength(pLinkMan phb);

/************************************************************************/
/* Function:    InsertLinkMan                                                                                         */
/* Description:    Insert a linkman to a phonebook                                                */
/* Parameters:                                                                                                                    */
/* phb: phonebook , index: the insert position    man: new linkman                */
/* Value: void                                                                                                                    */
/* Author: Hoiman                                                                                                             */
/* Date: 2010/11/05                                                                                                         */
/************************************************************************/
void InsertLinkMan(pLinkMan *phb, int index, pLinkMan man)
{
  int i = 0;
  pLinkMan pTemp = *phb;
  if (index <= 0)
  {
    printf("The index must be bigger than zero.\n");
    return;
  }
  else if (index > GetPhbLength(*phb) + 1)
  {
    printf("The index is bigger than the length of phonebook.\n");
    return;
  }
  else
  {
    if (1 == index)
    {
      if (pTemp != NULL)
      {
        man->next = pTemp->next;
        *phb = man;
      }
      else
      {
        *phb = man;
        man->next = NULL;
      }
    }
    else
    {
      for (i = 2; i < index; ++i)
      {
        pTemp = pTemp->next;
      }
      man->next = pTemp->next;
            pTemp->next = man;
    }
  }
}

/************************************************************************/
/* Function:    DeleteLinkManByName                                                                             */
/* Description:    Delete a linkman from a phonebook by name                            */
/* Parameters:                                                                                                                    */
/* phb: phonebook , name: the name of linkman will be deleted                     */
/* Value: void                                                                                                                    */
/* Author: Hoiman                                                                                                             */
/* Date: 2010/11/05                                                                                                         */
/************************************************************************/
void DeleteLinkManByName(pLinkMan *phb, char *name)
{
  int i = 0;
  pLinkMan pTemp = *phb;
  pLinkMan pPrior = pTemp;
  int length = GetPhbLength(*phb);
  for(i = 0; i < length; ++i)
  {
    if (0 == strcmp(pTemp->name,name))
    {
      if (0 == i)
      {
        *phb = (*phb)->next;
        //栈上的空间不能用free进行释放
        free(pTemp);
        return;
      }
      else
      {
        pPrior->next = pTemp->next;
        //栈上的空间不能用free进行释放
             free(pTemp);
        return;
      }
    }
    else
    {
      pPrior = pTemp;
      pTemp = pTemp->next;
    }
  }
  printf("Can't find the linkman in phonebook!\n");
}

/************************************************************************/
/* Function:    GetPhbLength                                                                                            */
/* Description:    Get the number of linkman in phonebook                                 */
/* Parameters:                                                                                                                    */
/* phb: phonebook                                                                                                             */
/* Value: the number of linkman                                                                                 */
/* Author: Hoiman                                                                                                             */
/* Date: 2010/11/05                                                                                                         */
/************************************************************************/
int GetPhbLength(pLinkMan phb)
{
  int count = 0;
  pLinkMan pTemp = phb;
        while(pTemp != NULL)
  {
    pTemp = pTemp->next;
    ++count;
  }
  return count;
}

/************************************************************************/
/* Function:    DestroyPhb                                                                                                */
/* Description:    Destroy the phonebook                                                                    */
/* Parameters:                                                                                                                    */
/* phb: phonebook                                                                                                             */
/* Value: void                                                                                                                    */
/* Author: Hoiman                                                                                                             */
/* Date: 2010/11/05                                                                                                         */
/************************************************************************/
void DestroyPhb(pLinkMan *phb)
{
  pLinkMan pTemp = *phb;
  while (*phb != NULL)
  {
    *phb = (*phb)->next;
    //栈上的空间不能用free进行释放
    free(pTemp);
    pTemp = *phb;
  }
}

/************************************************************************/
/* Function:    PrintPhb                                                                                                    */
/* Description:    print the phonebook                                                                        */
/* Parameters:                                                                                                                    */
/* phb: phonebook                                                                                                             */
/* Value: void                                                                                                                    */
/* Author: Hoiman                                                                                                             */
/* Date: 2010/11/05                                                                                                         */
/************************************************************************/
void PrintPhb(pLinkMan phb)
{
  while(phb != NULL)
  {
    printf("name: %s\n",phb->name);
    printf("num: %s\n",phb->num);
    phb = phb->next;
  }
}