A programming paradigm centered around actions or occurrences signals, user interactions, or messages to dictate the flow of execution. Instead of a program following a predetermined sequence of instructions, it reacts to these happenings. For instance, a user clicking a button on a graphical interface initiates a function to be executed, controlling application behavior.
This model facilitates responsiveness and adaptability, particularly in user interfaces and real-time systems. Its design allows for greater concurrency and efficient resource utilization, as the system only performs operations when specific events occur. This approach departs from traditional linear execution and has gained prevalence in developing interactive and reactive applications.