How do the Strategy design pattern and State design pattern differ from each other?

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The Strategy pattern and State pattern have some similarities as both are behavioral design patterns that focus on the behavior of an object. However, they have different goals and solve different types of problems.

The Strategy pattern defines a family of algorithms or behaviors and encapsulates each of them into separate classes, allowing objects to dynamically switch between them at runtime. It is often used to provide a way to change the behavior of an object without altering its structure. This pattern helps to decouple the behavior from the context where it is used, making the code more maintainable and reusable.

On the other hand, the State pattern is used when an object's behavior changes depending on its internal state. It allows an object to alter its behavior when its internal state changes. It is used to provide a way to change the object's behavior at runtime without changing the object's class. The State pattern is best suited for cases where an object's behavior depends on its state, and the number of states is relatively small.

In summary, the Strategy pattern is used to change an object's behavior dynamically, whereas the State pattern is used to change an object's behavior depending on its internal state.