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Why I should using the namespace instead the class? Where is the main difference? For example, in JavaScript the namespace can be emulated by classes. So, what the point to create namespace instead class?

Evgeniy
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    Does this answer your question? [Difference between classes and namespaces?](https://stackoverflow.com/questions/3188156/difference-between-classes-and-namespaces) – Rohan Bari Apr 30 '20 at 17:15
  • You can't create instances of a `namespace`; you can create instances of a `class`. – Thomas Matthews Apr 30 '20 at 17:40

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A namespace is just a way to separate and group identifiers to avoid naming conflicts at compile-time. A class is an actual type that you can allocate memory for and create instances of.

Remy Lebeau
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Consider an analogous question: What is the main difference between an office chair and a train? You can emulate an office chair by sitting on a train. What is the point of using an office chair instead of a train?

Classes are a types. It is possible to instantiate objects of types. For example:

class foo{}; // a class
foo f;       // this variable is instance of the class

Namespaces are not types. It is not possible to create instances of namespaces.

Furthermore, it is possible to have template classes:

template<typename T>
struct bar{};

It is not possible to have namespace templates.

On the other hand, it is possible to have anonymous namespaces, and it is possible to bring members of a namespace into another namespace with using declaration, which is not possible with members of a class.

So, what the point to create namespace instead class?

We need to group names into smaller scopes to avoid name collisions. That is what namespaces are for.

Classes have a scope as well sure, but when we don't need a type, there is no point in defining a class.

eerorika
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