problem with linklist

[sunilsomanna]

template<class T>
void TimerDLList<T>::addFirst(TimerItem<T>* const itemPtr)
{
// suppose itemPtr is not pointing to NULL

itemPtr->prev = (TimerItem<T>*) NULL;

head = (TimerItem<T>*)NULL;

if (tail == (TimerItem<T>*)NULL ) // nothing in the link list
{
tail = itemPtr;
itemPtr->next = (TimerItem<T>*) NULL;
}
else
{
itemPtr->next = head;
head->prev = itemPtr;
}

head = itemPtr;
}

there seems to be some problem in head->prev = itemPtr.
There seems to be some corrution at this point.
PLEASE HELP.......
seems like head->prev is accessing a wrong address.

[Thomas Lumley]

On Jul 5, 8:05 am, [e-mail] wrote:

template<class T>
void TimerDLList<T>::addFirst(TimerItem<T>* const itemPtr)

Looks like C++ to me. You may want comp.lang.c++ or a platform-
specific newsgroup, but not comp.lang.c.

-thomas

[Jens Thoms Toerring]

su**********@gmail.com wrote:

template<class T>
void TimerDLList<T>::addFirst(TimerItem<T>* const itemPtr)

This looks lik C++, but this comp.lang.c, not comp.lang.c++.

{
// suppose itemPtr is not pointing to NULL

itemPtr->prev = (TimerItem<T>*) NULL;

head = (TimerItem<T>*)NULL;

if (tail == (TimerItem<T>*)NULL ) // nothing in the link list
{
tail = itemPtr;
itemPtr->next = (TimerItem<T>*) NULL;
}
else
{
itemPtr->next = head;
head->prev = itemPtr;
}

head = itemPtr;
}

there seems to be some problem in head->prev = itemPtr.

When you first set 'head' to NULL then you shouldn't be too
astonished when you can't dereference it later on...

Regards, Jens
--
\ Jens Thoms Toerring ___ [e-mail]
\__________________________ http://toerring.de

[Martin Ambuhl]

su**********@gmail.com wrote:

template<class T>
void TimerDLList<T>::addFirst(TimerItem<T>* const itemPtr)

There are languages in which the above makes sense (C++ springs to
mind), but C is not one of them. If your question is about the
programming language C++, you might find an answer if you posted to a
C++ newsgroup. <news:comp.lang.c++is one of those. If it is some
other language, you will need to look for the appropriate newsgroup.