Huh---that doesn't work on my clang at home.

It would be nice if the kata were explicit about whether being "in order" was case-sensitive, whether it applied to non-alpha characters, etc. I'm still not sure what the original intent of the kata is.

Much more tenuously, it might be nice to use a better type than a string as the return value in languages where that makes sense---in C++, something like enum class ordering { in_order, in_reverse_order, not_in_order }.