Frank Millman wrote:
Thanks to all for the various replies. They have all helped me to
refine my ideas on the subject. These are my latest thoughts.
Firstly, the Decimal type exists, it clearly works well, it is written
by people much cleverer than me, so I would need a good reason not to
use it. Speed could be a good reason, provided I am sure that any
alternative is 100% accurate for my purposes.
[snip]
For addition, subtraction, multiplication and division, the 'other'
number can be any of 2, 3, or 4 above. The result is a new Number
instance. The scale of the new instance is based on the following rule
For addition and subtraction . . .
For multiplication . . .
For division . . .
Out of curiosity, what is the purpose of these numbers? Do they
represent money, measurements, or something else? The reason I ask is
way back in physics class (or maybe chemistry... it was way back :) I
was introduced to the idea of significant digits -- that idea being that
a measured number is only accurate to a certain degree, and calculations
using that number therefore could not be more accurate. Sort of like a
built-in error range.
I'm thinking of developing the class in the direction of maintaining the
significant digits through calculations... mostly as I think it would be
fun, and it also seems like a good test case to get me in the habit of
unit testing. I'll call it something besides Number, though. :)
Is anybody aware of such a class already in existence?
--
Ethan
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