Nonvirtual member functions

• int num(void) - return the number of UIObjects in the list.
• UIObject *item(char *) - return the first interface object which has the given name, or NULL if none found.
• UIObject *item(int) - returns the Nth user interface object.
• int register_UI(UIObject *) - adds a new user interface object to the current list, and returns its index.
• void reset_UI(void) - calls the reset() routine for all registered UIObjects.
• void init_UI(void) - calls the init() routine for all registered UIObjects.
• void update_UI(void) - calls the update() routine for all registered UIObjects.
• void check_event_UI(void) - calls the check_event() routine for all registered UIObjects. This will cause them to see if any events are pending, and if so new Command objects will be put in the command queue.
• void act_on_command(Command *) - this is called after a Command has been executed, in order to inform all the user interface components about the possible change. Each Command has a unique code, and each UIObject will make a note of which command's they are interested in. This routine will call the act_on_command routine for each UIObject which has expressed interest in the command.