Store/Print Linked list

[EdWar82]

Am I not storing my linked list correctly? Or am I just not printing correctly? Can any direct me to what I am doing incorrectly? The only value that I get printed out is the 12. Thank you for any help/advice.

list.h

 #ifndef LIST_H
#define LIST_H

#include <iostream>
using namespace std;

class LinkedList
{
private:
	struct Node
	{
		int data;
		Node * next;
		Node * prev;
	};
	Node * head, * tail;
public:
	LinkedList();
	bool add(int val);
	void print() const;
	
};


#endif 

list.cpp

#include "list.h"


LinkedList::LinkedList()
{
		
}


bool LinkedList::add(int val)
{
	Node * newNode;

	newNode = new Node;  //Creates new node
	newNode->data = val; //Stores val
	newNode->next = nullptr;

	head = nullptr;

	if (head == nullptr)
	{
		head = newNode;
		tail = newNode;
	}
	else
	{
		tail->next = newNode; //Insert new node at the end of the list
		tail = newNode;
	}


	return head;
}


void LinkedList::print() const
{
	Node * current;

	current = head;

	while (current != nullptr)
	{
		cout << current->data << endl;
		current = current->next;
	}
}

app.cpp

#include "list.h"

int main()
{
	LinkedList aList;

	aList.add(3);
	aList.add(10);
	aList.add(1);
	aList.add(7);
	aList.add(9);
	aList.add(12);
	aList.print();
	

	system("pause");
	return 0;
}

[EdWar82]

Looks like I got it figured out. For some reason I had head = nullptr which was always making head == nullptr always true..