State Machines

A state machine is a behavioral model in computer science that describes a system using a finite number of conditions, or "states." At any given moment, the system exists in only one of these states and can move to another—a process called a "transition"—only when a specific input or event occurs. This simple yet powerful concept is fundamental for designing predictable, event-driven systems, and is widely used in everything from controlling traffic lights and vending machines to designing complex software like video game AI, user interfaces, and network protocols.