Chapter 5 - User Interface

Creating and managing the user interface elements (e.g., windows, buttons, menus)

Allow users to operate and manage the applications through its own user interfaces.

A top window that includes all other UI objects or widgets that are logically and/or spatially subordinate to it

Are handled by the interrupt mechanism of the system software (operating system).

Is a signal to the processor indicating that an event (usually an I/O event) has occurred and must be handled

A rectangular portion of the screen associated with a given application that is used as a space and channel for interacting with the application.

First initialization part of the program creates the necessary UI objects for the application and declares the event-handler functions and procedures for the created UI objects.

Purely computational will simply be carried out by executing the event-handler procedure.