Event Handling

• Most, if not all, GUI systems and toolkits are designed to be event driven, meaning that the main flow of your program is not sequential from beginning to end.

• When something happens that is of interest to you (an event), the system or toolkit calls a bit of your code that deals with that event (event handler).

• When your event handler finishes, control returns to the “main loop” and your program waits for the next event.