ليست پيوندي دو طرفه به زبان ++C

پياده سازي ليست پيوندي دو طرفه به زبان ++C

// dLinkList.cpp: implementation of the dLinkList class.
//
//////////////////////////////////////////////////////////////////////

#include "dLinkList.h"
#include
#include


//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

dLinkList::dLinkList()
{
   Front = NULL;
   Rear = Front;
   Count = 0;
}

dLinkList::~dLinkList()
{
  NodePtr current, temp;

   current = Front;
   while (current != NULL)
      {
      temp = current;
      current = current->Right;
      delete temp;
      }

   Front = NULL;
   Rear = Front;
   Count = 0;

}
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*                           InsertFirst                                */
/* Task:   To insert a new node containing Item at the front of the list*/
/* Given:  Item:  A data item                   */
/* Return: Nothing       */
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

void dLinkList::InsertFirst(char item)
   {
   NodePtr current;

   current = new Node;

   if (current == NULL)
      {
      cerr << "Memory allocation error!" << endl;
      exit(1);
      }
   current->Right = Front;
   current->Left  = NULL;
   current->Info  = item;

   Front = current;

   if (Count == 0)
      Rear = current;
   else
      Front->Left = current;
   Count++;
   }

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*                           InsertLast                                 */
/* Task:   To insert Item into a new node added to the rear of the list.*/
/* Given:  Item   A data item                   */
/* Return: Nothing       */
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

void dLinkList::InsertLast(char item)
   {
    NodePtr current;

   current = new Node;

   if (current == NULL)
      {
      cerr << "Memory allocation error!" << endl;
      exit(1);
      }
   current->Right = NULL;
   current->Left  = Rear;
   current->Info  = item;

   if (Count == 0)
      Front = current;
   else
      Rear->Right = current;
   Rear = current;
   Count++;
   }

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*                           RemoveFirst                                */
/* Task:   To remove first node from the list.                          */
/* Given:  Nothing                              */
/* Return: Data item that removed from the list    */
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

void dLinkList::RemoveFirst(char &item)
   {
   NodePtr current;
  
   if (Count == 0)
      {
      cerr << "ERROR: there is no item to remove in the list!" << endl;
      exit(1);
      }

   current = Front;
   item = current->Info;
   Front = current->Right;
   Front->Left = NULL;
   Count--;

   if (Count == 0)
      Rear = Front;

   delete current;
   }


/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*                           ShowList                                   */
/* Task:   Show all data item of the list.                         */
/* Given:  Nothing        */
/* Return: Nothing                         */
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

void dLinkList::ShowFirstToLast(void)
   {
   NodePtr current;

   current = Front;
   while (current != NULL)
      {
      cout<< current->Info<      current = current->Right;
      }