Event-driven programming is a programming paradigm that focuses on designing software systems based on events, which can be user actions, sensor outputs, or other occurrences. In event-driven programming, the flow of the program is determined by events and their handling rather than through a sequential execution of code. The main concept in event-driven programming is the event, which represents an occurrence that triggers a response or action. Events can be generated by various sources such as user interactions with graphical user interfaces (GUI), network communication, hardware devices, or timers. The event-driven model typically consists of three components: event sources, event handlers (also known as event listeners or callbacks), and an event loop. 1. Event Sources: These are entities that generate events. Examples include buttons in a GUI application, mouse movements, keyboard inputs, network sockets receiving data, or timers expiring. 2. Event Handlers: These are functions or blocks of code that execute in response to specific events. They are associated with an event source and perform the necessary actions when the corresponding events occur. 3. Event Loop: The event loop is responsible for continuously monitoring the system for events and dispatching them to their respective event handlers. It ensures that events are processed in a timely manner without blocking or interrupting the normal flow of the program. Event-driven programming offers several advantages: 1. Responsiveness: By responding to specific events as they occur, applications can provide immediate feedback to users and handle real-time updates efficiently. 2. Modularity: Event-driven programs are often modular since each component focuses on handling specific events independently. This promotes code reusability and easier maintenance. 3. Scalability: Event-driven architectures can handle multiple simultaneous events efficiently without blocking other operations. This makes them suitable for concurrent processing and handling large-scale applications. 4. Extensibility: New functionality can be easily added by defining new event handlers without modifying existing code extensively. Event-driven programming is widely used in various domains, including graphical user interfaces (GUI), web development, game development, and embedded systems. Popular event-driven programming frameworks and libraries include JavaScript's event handling in web browsers, Java's Swing GUI framework, and Node.js for server-side event-driven programming.