Is there an equivalent of the decimal type in D?
Bill Baxter
dnewsgroup at billbaxter.com
Sat Jan 27 14:41:35 PST 2007
Sean Kelly wrote:
> I'm not sure that accuracy is a problem--at least not compared to
> fixed-point BCD. The essential issue with using base 2 floating point
> for problems where the user expects an "exact" result in base 10 is that
> of representation. Simply put, some numbers that have an exact
> representation in base 10 are infinitely repeating numbers in base 2,
> and vice-versa. This is why a calculation resulting in 1.5 in base 10
> displays as 1.4999... in base 2. But as far as accuracy is concerned,
> I'm sure you'll agree that 1.4999... is not terribly far from 1.5 :-) Of
> course, finance folks don't see it this way because if you display
> 1.4999 on a report it doesn't match what they expect and they scream and
> yell.
Bad example. 1.5 *is* exactly representable in base 2 floating point.
2^0 + 2^-1 :-)
--bb
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