Traversing linked list help

Hi all, I'm in need of some help.
I made a simple linked list, but when I try to traverse through it in reverse, I keep getting a "exception error"...can someone shed any light on where I'm going wrong?
Please and thank you

Code:

---


struct Node
{
        int Data;
        Node *next;
        Node *prev;
};

int main()
{

        Node *head = new Node;
        Node *current, *tail;
        current = head;
        tail = head;
        cout << current << endl;
        cout << tail << endl;
        cout << head << endl;
        //all current,head,and tail point to the same location in the heap

        //NOW COMES THE HARD PART
        current->Data = 0;
        current->prev = NULL;
        //the head's previous is now point to null

        for(int i = 1; i <= 10; i++)
        {
                current->next = new Node;
                current->next->Data = i;
                current = current->next;
                tail = current->prev;
                tail = current;
        }

        current->next = NULL;

        while(tail != NULL)
        {
                cout << tail->Data << endl;
                tail = tail->prev; //why is tail not being able to capture the previous location?
        }

        cout << "data in tail: " <<  tail->Data << endl;
        //cout << tail->prev->Data << endl; //at this line, I receive compile error
        //a bunch of question marks pop up
        //why is tail not being able to hold the previous node's address???

---

You omitted one step in this loop:

Code:

---

for(int i = 1; i <= 10; i++)
        {
                current->next = new Node;
                current->next->Data = i;
                current = current->next;  // You went wrong here. You have now dropped your handle on the
                                          // "old" current node without setting the prev pointer of the new node
                tail = current->prev; // You don't know where current->prev is pointing.
                tail = current;
        }

---

Instead, you should have:

Code:

---

for(int i = 1; i <= 10; i++)
        {
                current->next = new Node;
                current->next->prev = current;  // You NEED this.
                current->next->next = NULL;    // This would be a good idea too.  All pointers should be set
                                              // when the new node is created.  Then you can eliminate the
                                              // "current->next = NULL;" line that you had after the end of the loop.
                current->next->Data = i;
                current = current->next;
                tail = current;
        }

---

Thanks Stiltskin that fixed the error I kept on receiving!!