#include <iostream>
using namespace std;

#define null 0

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

void addToListRef( Node* &thelist, int number);
Node* addToListVal( Node* thelist, int number);

int main()
{
   Node* list = new Node;
   (*list).data = 1;  // These next 2 lines are equivilant
   list -> data = 1;
   list -> next = null;
   //list -> next = '\0';

   addToListRef( list, 2 ); 
   list = addToListVal( list, 3 );
   addToListRef( list, 4 );
   list = addToListVal( list, 5 );

   for ( int i = 0; i < 5; i++ )
   {
      cout << list -> data <<endl;
      list = list -> next;
   }
}

void addToListRef( Node* &thelist, int number ) 
{
   Node* nodeToAdd = new Node;
   nodeToAdd -> data = number;
   nodeToAdd -> next = null; 

   if ( thelist == null )    //list is empty
   {
      thelist = nodeToAdd;
      return;
   }
   else      //list is not empty
   {
      Node* list = thelist;
      while ( list -> next != null  )
      {
        list = list -> next;
      }
      list -> next = nodeToAdd; 
   }

}

Node* addToListVal( Node* thelist, int number )
{
   Node* nodeToAdd = new Node;
   nodeToAdd -> data = number;
   nodeToAdd -> next = null;

   if ( thelist == null )
   {
      return nodeToAdd;
   }
   else
   {
      Node* list = thelist; 
      while ( thelist -> next != null )
      {
         thelist = thelist -> next;
      } 
      thelist -> next = nodeToAdd;
      return list; 
   }
}