I'm a bit confused. Shouldn't this:

    X<b> x;

be this:

    X<B> x;

Or am I confusing things? Also, I assume the `</b>` at the end is a typo?

Furthermore, I wasn't even aware you could access `a` the way it's being accessed in the same example; I always use `this->a`. Actually, I'd access `x` through `this->x` anyway, in case there's a lvar in the context. Although, I rarely write C++ anyway.