How to add an element at the nth place of a doubly linked list?

Question

OOP

I can not implement the function of adding an element to the list, each time the list is recreated and there is always 1 element
.cpp file

#include "List.h"



void List::show()
{
  Node *tmp = head;
  while (tmp != NULL)
  {
    cout << tmp->str <<endl; 
    tmp = tmp->next;
  }
}

void List::add(int x, string str2)
{
  Node *temp = new Node;
  temp->next = NULL;
  temp->str = str2;  
  temp->priority = x;

  if (head != NULL)
  {
    Node *quest = found(x);
    temp->prev = quest;
    temp->next = quest->next;
    if (quest == head)
    {
      head = temp;
    }
    if (quest == tail)
    {
      tail = temp;
    }
  }
  else
  {
    temp->prev = NULL;
    head = tail = temp;
  }
}

void List::delet()
{
  tail = tail->prev;
}

Node * List::found(int priority)
{
  if (head->next!=NULL)
  {
    if (search->priority == priority)
      return search;
    else
      return search = search->next;
  }
  else
  {
    return head;
  }
}

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


List::~List()
{
}

Answer 1

I would like to see the full code, because it is not clear how found works and what search is at each stage