Maybe I am wrong, but is the author just looking for a decimal type? Those exist in most major languages, right?
Sure, 0.1 can be represented exactly. But that's about the only issue with floating-point that that solves.
He could also use fdlibm ( http://netlib.org/fdlibm/index.html ), at least for anything other than primitive operations. But, again, it trades performance for consistency.