What is an 'event-driven' programming model?

An event-driven programming model is characterized by the program's execution flow being dictated by events, which can include user actions (like clicks, key presses, or gestures), sensor outputs, or messages from other programs or systems. This approach allows developers to create applications that are responsive to the environment and user input, leading to a more interactive and dynamic user experience.

In this model, instead of running through a straight line of code from start to finish, the program uses event listeners or handlers that wait for specific events to occur. Once an event is detected, the corresponding event handler is invoked to process that event. This paradigm enables the program to run more efficiently by only executing code in response to actual events, making it particularly useful for graphical user interfaces (GUIs), real-time systems, and applications that require ongoing interaction.

Comparatively, other options describe programming models that do not align with the event-driven paradigm. A model that only executes code based on a timer triggers events but lacks the broader responsiveness characteristic of event-driven systems. A model that runs code linearly and sequentially does not account for events or user input, while a focus on background processing without user interaction fails to leverage the immediate responsiveness that event-driven programming provides.