On 2/21/11 4:48 AM, Jonathan M Davis wrote:
On Monday 21 February 2011 01:55:28 Walter Bright wrote:
Kevin Bealer wrote:
1. To solve the basic problem the original poster was asking -- if you
are working with simple decimals and arithmetic you can get completely
accurate representations this way. For some cases like simple financial
work this might work really well. e.g. where float would not be because
of the slow leak of information with each operation. (I assume real
professional financial work is already done using a (better)
representation.)
A reasonable way to do financial work is to use longs to represent pennies.
After all, you don't have fractional cents in your accounts.
Using floating point to represent money is a disaster in the making.
Actually, depending on what you're doing, I'm not sure that you can legally
represent money with floating point values. As I understand it, there are
definite
restrictions on banking software and the like with regards to that sort of thing
(though I don't know exactly what they are).
This is a long-standing myth. I worked on Wall Street and have friends
who have been doing it for years. Everybody uses double.
Andrei
