
   void ADDRESS_BOOK_TREE::alloc_data(NODE *to_node, void *from_data)
      {
      ADDRESS_BOOK_ENTRY *to = to_node->data;
      ADDRESS_BOOK_ENTRY *from = from_data;

      to->name = new char[strlen(from->name)+1];
      strcpy(to->name, from->name);

      to->street_address = new char[strlen(from->street_address)];
      strcpy(to->street_address, from->street_address);

      // etc. for other fields in an ADDRESS_BOOK_ENTRY
      }

   void ADDRESS_BOOK_TREE::delete_data(NODE *nptr)
      {
      ADDRESS_BOOK_ENTRY aptr = nptr->data;

      delete to->name;
      delete to->street_address;
      delete to->city;
      delete to->state;
      zip = 0L;
      }

   void ADDRESS_BOOK_TREE::compare(void *v1, void *v2, size_t size)
      {
      // This function compares the names in each entry, returning
      // <0 if d1->name < d2->name, 0 if d1->name == d2->name, 
      // and >0 if d1->name > d2->name.  This is very easy to do 
      // by using the strcmpl() function.  In this case the 'size'
      // argument is irrelevant.

      ADDRESS_BOOK_ENTRY *d1 = v1, *d2 = v2;

      return strcmpl(d1->name, d2->name);
      }

