State

State is the fundamental concept of computer programming, making the foundation of application development and system design. A state is some arrangement of data or an action waiting to be performed that a program or system can be in. A single program or system may contain multiple states, and the flow of the program is determined by the transitions between those states.

In computer programming, states are usually represented by elements in a programming language such as variables or data structures. Each state of a program is expressed through the values of these elements. For example, a program might keep two variables – a “score” and a “lives” – to track the state of a game. The current period of time when the program is in this particular state is called its “instance.”

In complex software systems that store data in a database or on a server, the state may be more complex. An application might store data on the users, the actions that the user has taken, and the resources available to the user. Information about all these elements might be combined into a single state.

State machines are used to model computer programs and to make sure that valid operations can only take place in valid states. A state machine will enforce that only valid data can be put into the system, and will also process data correctly when changes to state occur. State machines are widely used in applications that must predictably handle user input and control hardware components or communicate with other computers.

State can also refer to the measurement of a system’s properties such as memory or inputs at a given time, in that state. Additionally, state can be used to describe the current version of a piece of software that was saved and is now running.

State is essential for computing and programming, and variations of this concept will be used in any time when developers plan to create an application. Keeping track of what data, tasks, and actions a system currently has available is key to maintaining stability and reliability.

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