Question

I was just reading a little bit on them from http://www.cplusplus.com/doc/tutorial/namespaces/
and it seems like a struct is capable of the same things? Or even a class for that matter. Maybe someone here can better define what a namespace is, and how it differs from a struct/class?

Answer 1

Namespaces and class-types are not capable of the same things. Namespaces are mainly used to group types and functions together to avoid name collisions, while class-types hold data and operations that work on that data.

To just group functions and objects by using a class-types you’d have to make them static:

struct X {
    static void f();
};

Without static you’d have to create instances of the class-types to use them. A namespace is much better suited here:

namespace X {
    void f();
}

Another important thing are using declarations and directives:

namespace X {
    void f();
    void g();
}

void h() {
    using X::f;
    f(); // f() now visible in current scope
    using namespace X;
    f(); g(); // both visible
}

With class-types there simply is no mechanism that allows that.

What class-types give you over namespaces is that you can have multiple instances with differing state – if you need that use a class-type.