Does C++ allow you to define explicit casts?

I don't know C++ that well, and the book I have on it (Stroustrop, 2nd ed, I think) is 10 years old at least. XEmacs has typedefs such as Bytecount and Charcount. Currently they are just ints but I'd like to introduce some additional type-checking using C++. In particular, I'd like to define them as classes, with the normal operators overloaded in normal ways, and to allow free mixing (more or less) between these types and ints (at the very least, it's reasonable to pass constant ints to a function expecting a Bytecount or Charcount). What I don't want is to be able to pass one of them to a function expecting the other -- but it *should* be possible with an explicit cast, e.g. (Bytecount) x. Problem is, the "cast operator" that can be defined on a class seems to define implicit casts, not explicit. Is there any way to do what I want? ben