Not necessarily. If all the classes indeed belong to the category defined by the namespace, it's fine then.
What you can do is to look at the classes and reflect on the possibility of merging some of them. Could well be small groups of those classes support "family" functionality but were implemented separately for some historic reasons. Now when sufficient time has elapsed, a better composition might be possible.
Using static classes as namespaces defies the purpose of having namespaces.
The key difference is here:
If you define CategoryA, CategoryB< as namespaces, and when application uses two namespaces :
CategoryA::Item1 item = new CategoryA::Item1();
CategoryB::Item1 item = new CategoryB::Item1();
Here if the CategoryA or CategoryB is a static class rather than namespace, the usage for the application is almost same as described above.
However, if you define it as a namespace and application uses only 1 namespace (doesn't include CategoryB), in that case application can actually use following
using namespace CategoryA;
Item1 item = new Item1();
But had you define CategoryA as a static class the above is undefined!
One is forced to write CategoryA.something every time.
Namespaces should be used to avoid naming conflicts whereas class hierarchy should be used when class grouping has some relevance to the system model.
Best Answer
Well, currently the main difference is a namespace is designed to be augmented in separate files. If you try to add a new nested class to a class, you get:
However, it only works that way because it was defined that way. It wouldn't be that difficult to rework the compiler to append to a class in certain ways when it sees what is now a redefinition.
The reason they don't is that a namespace and a class are conceptually two different things, used for different reasons. A class is meant to be instantiated, and is used to create strong cohesion between a data structure and its associated methods. A namespace is meant to loosely gather modules to make it easier to share groups of several files without causing naming clashes.
Yes, you can approximate the behavior of one using the other, but that doesn't make them the same. If you used a redefinition-allowed class instead of namespaces, you would have problems like:
StdNamespaceinstead of juststd.When you add up all the special cases you would need to handle to make it truly follow the open-closed principle, you may as well just call it a namespace.