How to detect a double's significant digits

[mrstephengross]

>But, assuming you have your numbers as strings, I would suggest
looking
at str.split() and len().

Well, the numbers are in fact stored as numbers, so string processing
won't work.

>I'd give you an example, but this sounds kinda like a homework
assignment.

The task may sound like it comes from class, but I can assure you that
I am indeed a professional developer. I'm doing some rather intricate
text processing / rendering stuff these days, and C++ is unfortunately
none too handy for that sort of thing. Unfortunately, I have to use it
for the task.

Thanks,
--Steve