743: Mainline

To get at element, you define access, which returns a pointer to a railroad_car object:

class header { 
  public: 
    link *first_link_pointer; 
    link *current_link_pointer; 
    header ( ) { 
      first_link_pointer = NULL; 
      current_link_pointer = first_link_pointer; 
    } 
    ... 
    railroad_car* access ( ) {                         
      return current_link_pointer -> element_pointer;  
    }                                                  
    ... 
};