Thread: Double linked lists

Yes. Now that will make your code more readable
Which is always a good thing.

Now, as for your question about the linked lists...? What was it again?

The prev pointer works pretty much like the next pointer, but points the other way around, so when you add something to a dlist, you link the prev-pointer of the new node to the previous node, and the next node of the previous node to the new node, for example.

The first nodes prev pointer is NULL [or whatever you use as a end-marker], and the last nodes next pointer is NULL.

--
Mats

Along the lines for a few scenarios of working with double-linked lists, here's a little source snippet from me to demonstrate how a linked list can work:

Code:

struct CLinkedListBeginOrEnd
{
	CLinkedList* pBegin;
	CLinkedList* pEnd;
};

CLinkedList* pPrevious;
CLinkedList* pNext;
CLinkedListBeginOrEnd* pBeginOrEnd;

void InsertAfter(CLinkedList* pAdd, CLinkedList* pAfter)
{
	CLinkedList* pNextNode = pAfter->pNext;
	CLinkedList* pPrevNode = pAfter;
	pPrevNode->pNext = pAdd;
	if (pNextNode) pNextNode->pPrevious = pAdd;
	pPrevious = pPrevNode;
	pNext = pNextNode;
	if (pNextNode == NULL) // We're the last node
		pBeginOrEnd->pEnd = this;
}

This was actual C++ code converted to C code, but I hope you may still find it relevant to understand how a double linked list works.
Remember: Don't copy. Understand how the code works and you'll get the hang of how a double-linked list works. Then make your own.