The Protected Search Elements:

    // ************************************ //
    // protected search agent               //
    // ************************************ // 
CHAR_DL_CELL* CHAR_DLLIST::get_element_address(CHAR search_key)
{
  CHAR_DL_CELL *temp;
  if(!(head==NULL)){
    temp = head;
    if(search_key==temp->element) return(temp);
    temp = head->next;
    while(!(temp==NULL)){
      if(search_key==temp->element) return(temp);      
      temp = temp->next;
      }
    }
  cout << "The element " << search_key << " is not in the list."
       << endl;
  return(NULL);
}

    // ************************************ //
    // find address before a given element  //
    // ************************************ // 
CHAR_DL_CELL* CHAR_DLLIST::get_before_element_address(CHAR search_key)
{
  CHAR_DL_CELL *temp;
  if(!(head==NULL)){
    temp = head;
    if(search_key==temp->element){
      cout << "search_key is at head of list, so before address is NULL"
           << endl;
      return(NULL);
      }
    while(!(temp->next==NULL)){
      if(search_key==temp->next->element){
        //temp is address of cell before cell containing search_key
        return(temp); 
        }     
      temp = temp->next;
      }
    }
  cout << "The element " << search_key << " is not in the list."
       << endl;
  return(NULL);
}

    // ************************************ //
    // find address after a given element  //
    // ************************************ // 
CHAR_DL_CELL* CHAR_DLLIST::get_after_element_address(CHAR search_key)
{
  CHAR_DL_CELL *temp;
  if(!(head==NULL)){
    temp = head;
    if(search_key==temp->element){
      cout << "search_key is at head of list, so after address is head->next."
           << endl;
      return(temp->next);
      }
    temp = temp->next;
    while(!(temp==NULL)){
      if(search_key==temp->element){
        //temp->next is address of cell after cell containing search_key
        return(temp->next); 
        }     
      temp = temp->next;
      }
    }
  cout << "The element " << search_key << " is not in the list."
       << endl;
  return(NULL);
}