Is there a better way to express nested namespaces in C++ within the header

Question

I switched from C++ to Java and C# and think the usage of namespaces/packages is much better there (well structured). Then I came back to C++ and tried to use namespaces the

Answer 1

To avoid really deep indenting, I usually do it this way:

namespace A { namespace B { namespace C
{
    class X
    {
        // ...
    };
}}}