742: Mainline

To advance the current_link_pointer down the list, you need advance, a member function that digs next_link_pointer out of the link identified by current_link_pointer:

class header { 
  public: 
    link *first_link_pointer; 
    link *current_link_pointer; 
    header ( ) { 
      first_link_pointer = NULL; 
      current_link_pointer = first_link_pointer; 
    } 
    ... 
    void advance ( ) {                                                  
      current_link_pointer = current_link_pointer -> next_link_pointer; 
    } 
    ...                                                          
};