// L-11 MCS 360 Fri 17 Sep 2010 : mcs360_list.tc

/* This file defines the member function of the templated class List
   in the namespace mcs360_list. */

#include <iostream>

namespace mcs360_list
{
   template <typename T>
   List<T>::List()
   {
      first = NULL;
      last = NULL;
   }

   template <typename T>
   List<T>::List(T item)
   {
      first = new Node(item);
      last = first;
   }

   template <typename T>
   void List<T>::append(T item)
   {
      if(first == NULL)
      {
         first = new Node(item);
         last = first;
      } 
      else if(first == last)
      {
         first->next = new Node(item);
         last = first->next;
      }
      else
      {
         last->next = new Node(item);
         last = last->next;
      }
   }

   template <typename T>
   void List<T>::write()
   {
      Node *ptr = first;
      while(ptr != NULL)
      {
         std::cout << "->" << ptr->data;
         ptr = ptr->next;
      }
   }

   template <typename T>
   bool List<T>::member(T item)
   {
      Node *ptr = first;
      while(ptr != NULL)
      {
         if(ptr->data == item) return true;
         ptr = ptr->next;
      }
      return false;
   }

   template <typename T>
   void List<T>::erase(T item)
   {
      if(first != NULL)
      {
         Node *current = first;

         if(current->data == item)
            first = first->next;
         else
         {
            Node *previous = first;
            current = first->next;
     
            if(current != NULL)
            {
               while((current->data != item)
                  && (current->next != NULL))
               {
                   previous = current;
                   current = current->next;
               }
               if(current->data == item)
               {
                  std::cout << "removing " << item << std::endl;
                  previous->next = current->next;
                  delete current;
               }
               if(previous->next == NULL)
                  last = previous;
            }
         }
      }
   }
}