Проблема вывода двунаправленного списка(а также возможна проблема в методе Swap(), хочу заменить в нём элемент, на новый)

#include <iostream>

using namespace std;

struct Node
{
    int data;
    Node *prev, *next;
};

class List
{
    Node *head, *tail;
    int count;

public:
    List ();
   ~List ();
    Node *GetElem (int);
    void DellAll ();
    void Dell (int pos);
    void Insert (int pos = 0);
    void TailAdd (int n);
    void HeadAdd (int n);
    void Print (int pos);
    Node *Swap (int pos, Node * elem);
    void Print ();
};

List::List ()
{
    head = tail = NULL;
    count = 0;
}

List::~List ()
{
    DellAll ();
}

void
List::HeadAdd (int n)
{
    Node *temp = new Node;
    temp->prev = NULL;
    temp->data = n;
    temp->next = head;

    if (head != 0)
        temp->prev = temp;
    if (count == 0)
        head = tail = NULL;
    else
        head = temp;
    count++;
}

void
List::TailAdd (int n)
{
    Node *temp = new Node;
    temp->next = NULL;
    temp->data = n;
    temp->prev = tail;
    
    if (tail != 0)
        temp->next = temp;
    if (count == 0)
        head = tail = temp;
    else
        tail = temp;
    count++;
}

void
List::Insert (int pos)
{
    if (pos == 0)
    {
        cout << "Enter a position";
        cin >> pos;
    }
    if (pos < 1 || pos > count + 1)
    {
      return;
    }
    if (pos == count + 1)
    {
        int data;
        cout << "Enter a new data:";
        cin >> data;
        TailAdd (data);
        return;
    }
    else if (pos == 1)
    {
      int data;
      cout << "Enter a new data:";
      cin >> data;
      HeadAdd (data);
      return;
    }
    int i = 1;
    Node *Ins = head;
    while (i < pos)
    {
        Ins = Ins->next;
        i++;
    }

    Node *PrevIns = Ins->prev;
    Node *temp = new Node;
    cout << "Enter a new data:";
    cin >> temp->data;
    
    if (PrevIns != 0 && count != 1)
        PrevIns->next = temp;

    temp->next = Ins;
    temp->prev = PrevIns;
    Ins->prev = temp;
    count++;
}

void
List::Print ()
{
    if (count != 0)
    {
        Node *temp = head;
        cout << "( ";
        while (temp->next != 0)
        {
            cout << temp->data << ", ";
            temp = temp->next;
        }
        cout << temp->data << " )\n";
    }
}

void
List::Dell (int pos)
{
  if (pos == 0)
    {
      cout << "Enter a position";
      cin >> pos;
    }

  if (pos < 1 || pos > count)
    {
      return;
    }

  int i = 1;

  Node *Del = head;
  while (i < pos)
    {
      Del = Del->next;
      i++;
    }


  Node *PrevDel = Del->prev;
  Node *AfterDel = Del->next;

  if (PrevDel != 0 && count != 1)
    PrevDel->next = AfterDel;

  if (AfterDel != 0 && count != 1)
    AfterDel->prev = PrevDel;


  if (pos == 1)
    head = AfterDel;
  if (pos == count)
    tail = PrevDel;

  delete Del;

  count--;
}

void
List::DellAll ()
{

  while (count != 0)
    Dell (1);
}

void
List::Print (int pos)
{

  if (pos < 1 || pos > count)
    {
      return;
    }

  Node *temp;

  if (pos <= count / 2)
    {

      temp = head;
      int i = 1;

      while (i < pos)
    {
      temp = temp->next;
      i++;
    }
    }
  else
    {
      temp = tail;
      int i = 1;

      while (i <= count - pos)
    {
      temp = temp->prev;
      i++;
    }
    }
  cout << pos << " element: ";
  cout << temp->data << endl;
}

Node *
List::GetElem (int pos)
{
  Node *temp = head;


  if (pos < 1 || pos > count)
    {
      return 0;
    }

  int i = 1;

  while (i < pos && temp != 0)
    {
      temp = temp->next;
      i++;
    }

  if (temp == 0)
    return 0;
  else
    return temp;
}

Node *
List::Swap (int pos, Node * elem)
{
  Node *temp = head;


  if (pos < 1 || pos > count)
    {
      return 0;
    }

  int i = 1;

  while (i < pos && temp != 0)
    {
      temp = temp->next;
      i++;
    }

  if (temp == 0)
    return 0;
  else
    temp = elem;
  return temp;
}

int
main ()
{
  List L;
  const int n = 10;
  int a[n] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  for (int i = 0; i < n; i++)
    if (i % 2 == 0)
      L.HeadAdd (a[i]);
    else
      L.TailAdd (a[i]);
  cout << "List L:\n";
  L.Print ();

  cout << endl;
  cin.get ();
  return 0;
}