Thread: Linked List print out

hey all,

there I was, thinking I have linked list pretty much figured out, and here I am now; confused with a very simple problem (i think). Anyways, below is a code, where I am trying to create two seperate linked lists, abd later print them out. If I do just one, everything works fine, but when I do two, I get everything twice, basically instead of getting 0 1 2 3 4 I get 0 1 2 3 4 0 1 2 3 4.

any suggestions?

axon

Code:

#include <iostream>
using namespace std;

struct Node {
	Node *pNext;
	Node *pPrev;
	int nData;
};

Node *pHead, *pTail;

void AppendNode( Node *pNode);
//appends node to end of list

void InsetNode(Node *pNode, Node *pAfter);
//insert node into the list after pAfter

void RemoveNode(Node *pNode);
//Remove specified node from list

void DeleteAllNodes();
//Delete the entire list

int main()
{
	Node *L1;
	Node *L2;

	//add items to linked list
	for ( int i = 0;  i< 5; i++ ) {
		L1 = new Node;
		L1->nData = i;
		AppendNode( L1 );
	}

	for ( i = 0;  i< 5; i++ ) {
		L2 = new Node;
		L2->nData = i;
		AppendNode( L2 );
	}

	//display all nodes
	cout << "-----------==LIST 1==--------------" << endl << endl;
	for ( L1 = pHead; L1 != NULL; L1 = L1->pNext ) {
		cout << L1->nData << endl;
	}

	cout << "-----------==LIST 2==--------------" << endl << endl;
	for ( L2 = pHead; L2 != NULL; L2 = L2->pNext ) {
		cout << L2->nData << endl;
	}

	return 0;
}

//========================================
void AppendNode( Node *pNode)
{
	if ( pHead == NULL ) {
		pHead = pNode;
		pNode->pPrev = NULL;
	} else {
		pTail->pNext = pNode;
		pNode->pPrev = pTail;
	}
	pTail = pNode;
	pNode->pNext = NULL;
}


//========================================
void InsetNode(Node *pNode, Node *pAfter)
{
	pNode->pNext = pAfter->pNext;
	pNode->pPrev = pAfter;

	if ( pAfter->pNext != NULL ) {
		pAfter->pNext->pPrev = pNode;
	} else {
		pTail = pNode;
	}
	pAfter->pNext = pNode;
}

//========================================
void RemoveNode(Node *pNode)
{
	if ( pNode->pPrev == NULL ) {
		pHead = pNode->pNext;
	} else {
		pNode->pPrev->pNext = pNode->pNext;
	} 

	if ( pNode->pNext == NULL ) {
		pTail = pNode->pPrev;
	} else {
		pNode->pNext->pPrev = pNode->pPrev;
	}
}

//========================================
void DeleteAllNodes()
{
	while ( pHead != NULL ) {
		RemoveNode( pHead );
	}
}