C++Talk.NET

Andrew Skouloudis · Guest

Hello people and merry christmas. I am trying to create a simple
linked list and it seems i am
doing something wrong with the DeleteNode function ...

#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>
#include "GenericStringClass2.h"
#include <string.h>

#define DEFAULT 0

class MACListPart
{
public:
// constructor
MACListPart();
~MACListPart();
MACListPart *GetNextPointer();

private:
friend class MACList;
String macAdr;
int data;
MACListPart *next;
};

class MACList
{
public:
//constructors
MACList();
~MACList();

//accessors
void PrintList(void);
void AddNode(const String& mac);
void DeleteNode(const String& mac);
bool FindNode(const String&);
// void DeleteList();
bool IsListEmpty();
int GetCount(void);

protected:
MACListPart *head;
MACListPart *current;

private:
int itsCount;
};

MACListPart::MACListPart(void)
{
next=NULL;
data=0;

// macAdr=..
}

MACListPart::~MACListPart(void)
{
cout << "Calling the default destructor for MACListPart ...
n";
if(this != NULL)
{

delete this;
}
else delete this;
}

MACListPart* MACListPart::GetNextPointer(void)
{
if(this==NULL)
{
cout << "You are pointing to nowhere , where do you
think you are going ??n";
return NULL;
}
else
{
return this->next;
}
}

MACList::MACList(void)
{
head=NULL;
current=NULL;
itsCount=0;
}

MACList::~MACList(void)
{/*
if(IsListEmpy()==true)
{
//do nothing ..
}
else
{
DeleteList();
}*/
}

bool MACList::IsListEmpty(void)
{
if(head==NULL)
{
return true;
}

//else ....
return false;
}

bool MACList::FindNode(const String& mac)
{
MACListPart *pMacListPart=head;
while(pMacListPart !=NULL)
{
if(pMacListPart->macAdr==mac)
{
return true;
}
}
return false;
}

int MACList::GetCount(void)
{
return itsCount;
}

void MACList::AddNode(const String& mac)
{
MACListPart *pMACListPart = new MACListPart;
pMACListPart->macAdr=mac;
pMACListPart->data=DEFAULT;
pMACListPart->next=NULL;

if(IsListEmpty() == true)
{
head=pMACListPart;
current=head;
}
else // (if IsListEmpty() == false )
{
current->next=pMACListPart;
current=pMACListPart;
}
// increasing the elements of the list
itsCount++;
}

void MACList::PrintList()
{
MACListPart *temp = head;
while( temp != NULL)
{
cout << temp->macAdr.GetString() << endl;
temp=temp->next;
}
}

void MACList::DeleteNode(const String& mac)
{
char c;
// If the first element of the list is going to be deleted:
if(head->macAdr==mac)
{
MACListPart *tempNode;
tempNode=head->next;
delete head;
head=tempNode;
}
else
{
MACListPart *prevNode,*currNode;
prevNode=head;
currNode=head->next;
while(currNode != NULL)
{
if(currNode->macAdr==mac)
{
MACListPart *tempNode;
tempNode=currNode->next;
prevNode->next=tempNode;
printf("YAHOOOOn");
this->PrintList();
c=getchar();
delete currNode;

}
else // you didn't find the string in currNode
so ...
{
prevNode=currNode;
currNode=currNode->next;
}
}
}
}

int main(void)
{
MACList MACListIstance;
MACListIstance.AddNode("11-11-11-11-11-11");
MACListIstance.AddNode("22-22-22-22-22-22");
MACListIstance.AddNode("33-33-33-33-33-33");
MACListIstance.AddNode("44-44-44-44-44-44");
MACListIstance.PrintList();
bool t = MACListIstance.FindNode("11-11-11-11-11-11");
MACListIstance.DeleteNode("22-22-22-22-22-22");
MACListIstance.PrintList();
if (t==true) cout << "This MAC address exists into the
database ... n";
else cout << "This MAC address does not exist in the
database.... n";
cout << "Hello world ... the list currently has " <<
MACListIstance.GetCount() << " elements n";
return 0;
}

The problem is when i am trying to delete a node .. The program hangs
after the command
delete currNode is executed ... The String class is declared in
another file and here is the
default destructor :

String::~String()
{
cout << "Calling the default destructor of String ..n";
delete [] itsString;
itsLen=0;
cout <<"Default destructor of String finished ... n";
}

Can you help ?? I am using Visual C++

(Sorry for my english ... )

Brian MacBride · Guest

"Andrew Skouloudis" <afterskoulNOSPAMPLEASE (AT) yahoo (DOT) com> wrote

Andrew Skouloudis · Guest

On Sun, 28 Dec 2003 12:22:14 -1000, "Brian MacBride"
<macbride (AT) ix (DOT) netcom.com> wrote:

Brian MacBride · Guest

"Andrew Skouloudis" <afterskoulNOSPAMPLEASE (AT) yahoo (DOT) com> wrote

Andrew Skouloudis · Guest

Michael Mellor · Guest

Andrew Skouloudis wrote:

Andrew Skouloudis · Guest

On Mon, 29 Dec 2003 13:16:29 +0000, Michael Mellor
<news-at- (AT) michaelmellor-dot- (DOT) com> wrote:

Brian MacBride · Guest

"Andrew Skouloudis" <afterskoulNOSPAMPLEASE (AT) yahoo (DOT) com> wrote

Brian MacBride · Guest

"Brian MacBride" <macbride (AT) ix (DOT) netcom.com> wrote

Wagner Bruna · Guest

Hi,

Andrew Skouloudis <afterskoulNOSPAMPLEASE (AT) yahoo (DOT) com> wrote

Andrew Skouloudis · Guest

On Mon, 29 Dec 2003 16:33:24 GMT, "Brian MacBride"
<macbride (AT) ix (DOT) netcom.com> wrote:

Andrew Skouloudis · Guest

On 29 Dec 2003 09:39:08 -0800, [email]wbruna (AT) yahoo (DOT) com[/email] (Wagner Bruna) wrote: