Explain the State design pattern.

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Explain the State design pattern.

The State design pattern is a behavioral design pattern that allows an object to alter its behavior when its internal state changes. It is used to model the behavior of an object based on its internal state, where the object's behavior is determined by a set of states and transitions between them.

In this pattern, the object's behavior is encapsulated in separate state classes, each representing a specific state. The object maintains a reference to the current state object, and delegates the behavior to the current state. When the object's state changes, it updates the reference to the new state object.

The State design pattern promotes loose coupling between the object and its states, as each state class handles its own behavior independently. This allows for easy addition of new states without modifying the existing code.

The State design pattern is commonly used in scenarios where an object's behavior changes based on its internal state, such as in state machines, user interfaces, or any system with multiple states and transitions between them.