[C++]Dubbelgelinkte lijst,wat is fout

[GAEvakYD]

Ik had een programma waar ik gebruik maakte van een enkelgelinktelijst. Nu ging ik dit uitbreiden om te bladeren door de objecten heen. Helaas ging dat niet goed. Ik heb de functie Add niet goed. Dat is dan nog maar van de enkelgelinkte lijst, ik kan er maar eentje terug bladeren en niet meer. Nu wil ik dus ook weer dieper de lijst in kunnen. Dus moest ik de Add functie uitbreiden zodat de Previous pointer etc ook goed gezet word. Dit lukt me dus voor geen meter.

---------------CQueue.h--------------------------

code:

class CData{
public:
CData( const char *contactname,
         const char *number1,
           const char *number2,
           const char *email); // Constructor
     CData();
     ~CData(){};//Destructor
     char * getContactname(){return contactname;}
     //pre: -
     //post: Returns the data in the variable 'documentnaam'

      char * getNumber1(){return number1;}
//pre: -
//post: Returns the data in the variable 'eigenaar'

      char * getNumber2(){return number2;}
//pre: -
//post: Returns the data in the variable 'status'

char * getEmail(){return email;}
//pre: -
//post: Returns the data in the variable 'datum'

 private:
  char *contactname;
   char *number1;
   char *number2;
    char *email;
};

class Node{
public:
      Node(){};
      ~Node(){};
      void SetInhoud(CData *cdD);
      void SetNext(Node *next2);
      void SetPrevious(Node *next3);
      CData * GetInhoud();
      Node * GetNext();
      Node * GetPrevious();
//private:
      CData *cdInhoud;
      Node *next;
      Node *previous;
};

class CQueue {
public:
CQueue():iTeller(0){}//Constructor
~CQueue(){}; // Destructor
bool isEmpty( );
      CData *first( );
      CData *next( );
      CData *previous( );
void add(CData *cdD );
void remove( );
void clear( );
int  getSize( ){return iTeller;}
private:
      Node *frontnode;
Node *backnode;
      Node *current;
int iTeller;
};

CQueue *CQueueInstant(){
CQueue *pcqQ = new CQueue;
return pcqQ;
}

extern CQueue *qQ; 
extern CData *data;

-------Cqueue.cpp-------------------------------

code:

#include <string.h>
#include <iostream.h>
#include <iomanip.h>
#include <time.h>
#include <windows.h>
#include <stdlib.h>
#include "database.h"

CQueue *qQ = CQueueInstant();
CData *data = 0;

//Add a new node to the linked list.
void CQueue::add(CData *cdD )
{
if (iTeller == 0)
{
  Node *temp = new Node;
  temp->next=frontnode;
  temp->cdInhoud=cdD;
  temp->previous=backnode;
  frontnode = temp;
  iTeller++;
}
else
{
  Node *temp = new Node;
  temp->next=frontnode;
  temp->cdInhoud=cdD;
  temp->previous=backnode;
  current = temp;
  iTeller++;
}
}

//Remove a node from the list.
void CQueue::remove( )
{
  Node *temp= frontnode ;
  Node *temp1;
  int iT=iTeller;

switch( iTeller )
{
case 0:
cout<<"The Que is empty !"<<endl;
    break;
case 1:
frontnode=NULL;
delete temp;
break;
case 2:
temp=temp->GetNext();
frontnode->SetNext(NULL);
delete temp;
break;
default :
    while (iT >= 3){
   temp=temp->GetNext();
   iT--;
}
temp1=temp->GetNext();
temp->SetNext(NULL);
delete temp1;
break;
}

iTeller--;
}

CData * CQueue::previous()
{
  Node *qTemp=frontnode;
  CData *dTemp;
  if (iTeller==0 || iTeller == 1)
    {

    }
  else
   {
    qTemp=qTemp->GetNext();
   }

   dTemp=qTemp->GetInhoud();
   return dTemp;
}

CData * CQueue::next()
{
  Node *qTemp=frontnode;
  CData *dTemp;
  if (iTeller==0 || iTeller == 1)
    {

    }
  else
   {
    qTemp=qTemp->GetPrevious();
   }

   dTemp=qTemp->GetInhoud();
   return dTemp;
}
//Return a pointer to the Data of the first node from the Que.
CData * CQueue::first()
{
Node *qTemp=frontnode;
CData *dTemp;
int iT=iTeller;
    if (iTeller==0)
{
cout<<"There is no data"<<endl;
}
else
{
while (iT >= 2){
   qTemp=qTemp->GetNext();
   iT--;
}
}
dTemp=qTemp->GetInhoud();
return dTemp;
}


//Clears the entire list.
void CQueue::clear( )
{
Node *qTemp=frontnode;

while (iTeller >= 1){
   frontnode=qTemp->GetNext();
   delete qTemp;
   qTemp=frontnode;
   iTeller--;
}
frontnode=NULL;
iTeller=0;
}

//Cheks if the list is empty.
bool CQueue::isEmpty( )
{
Node *qTemp=frontnode;
if (iTeller==0)
{
  return true;
}
else
{
  return false;
}
}

//Set function of the Data part for a Node.
void Node::SetInhoud(CData *cdD)
{
cdInhoud=cdD;
}

//Set function of the NextNode part for a Node.
void Node::SetNext(Node *next2)
{
next=next2;
}

void Node::SetPrevious(Node *previous2)
{
previous=previous2;
}



//Returns the NextNodepointer of a Node.
Node * Node::GetNext()
{
return next;
}

Node * Node::GetPrevious()
{
return previous;
}

//Returns the Inhoudpointer of a Node.
CData * Node::GetInhoud()
{
return cdInhoud;
}

//Returns a pointer to a new Que list.


//Constructor CData
CData::CData(const char *Contactname, 
    const char *Number1,
 const char *Number2,
 const char *Email)
{ 
     contactname = new char[strlen(Contactname)+1];
       number1 = new char[strlen(Number1)+1];
       number2 = new char[strlen(Number2)+1];
       email = new char[strlen(Email)+1];

 strcpy(contactname,Contactname);
 strcpy(number1,Number1);
 strcpy(number2,Number2);
 strcpy(email,Email);
}

--------functie.cpp--------------------------------------

code:

CData *InsertJob(char *CNaam, char *N1, char *N2, char *EM)
{
CData *temp= new CData(CNaam, N1, N2, EM);
return temp;
}
//---------------------------------------------------------------------------

void Clearfile(){

ofstream examplefile ("example.txt",ios::trunc);
}

//---------------------------------------------------------------------------

void Writedata(CData *cdDa, CQueue *qQueue)
{
  ofstream examplefile ("example.txt",ios::ate);
  if (examplefile.is_open())
  {

    examplefile <<  cdDa->getContactname() <<"\n";
    examplefile <<  cdDa->getNumber1() << "\n";
    examplefile <<  cdDa->getNumber2() << "\n" ;
    examplefile <<  cdDa->getEmail() << "\n";
    examplefile.close();
  }
}

//---------------------------------------------------------------------------

bool IsEmpty(char *String)
{
char string[50]="";
if (strcmp(String,string) == 0)
      {
      return false;
      }
else
      {
             return true;
      }
}

---------------------------------------------------------



Please help me

[Verwijderd]

Kan je de code even tussen [ code] tags zetten leest wat prettiger.

[GAEvakYD]

Hmm dit werkt zo niet, [ code] en aanhet einde [ /code]


wat doe ik fout?

[marcusk]

Op zaterdag 22 december 2001 16:35 schreef GAEvakYD het volgende:
Hmm dit werkt zo niet, [ code] en aanhet einde [ /code]


wat doe ik fout?

zonder de spaties

[D2k]

Op zaterdag 22 december 2001 16:35 schreef GAEvakYD het volgende:
Hmm dit werkt zo niet, [ code] en aanhet einde [ /code]


wat doe ik fout?

spatie weghalen

code:

blaat

[marcusk]

code:

void CQueue::add(CData *cdD )
{
  if (iTeller == 0)
  {
    Node *temp = new Node;
    temp->next = frontnode;
    temp->cdInhoud = cdD;
    temp->previous = backnode;
    frontnode = temp;
    iTeller++;
  }
  else
  {
    Node *temp = new Node;
    temp->next = frontnode;
    temp->cdInhoud = cdD;
    temp->previous = backnode;
    current = temp;
    iTeller++;
  }
}

ik heb niet je hele code doorgelezen, maar dat klopt iig niet. ik zou er dit van maken (ik neem aan dat je nieuwe nodes achteraan wilt invoegen):

code:

void CQueue::add(CData *cdD )
{
  Node *temp = new Node;
  temp->cdInhoud = cdD;

  if (iTeller == 0)
  {
    frontnode = backnode = temp;
  }
  else
  {
    backnode->SetNext(temp);
    temp->SetPrevious(backnode);
    backnode = temp;
  }

  iTeller++;
}

verder is het verstandig om je members (bv. frontnode, backnode, next, previous) in de constructor op 0 te initializeren.