On Sun, 31 Oct 2004 04:11:06 +0900, Francis Hwang <sera / fhwang.net> wrote:
> Well, it depends on what you're measuring. Some tasks need a finer
> resolution than others. One example: A few years ago, one of the major
> U.S. stock exhanges (NASDAQ, I think) went to a lot of trouble to
> convert from expressing stock prices in fractions to expressing them in
> pennies. Those prices used to be expressed as, for example, $16 3/4 or
> $16 3/8 (down to 1/8 or 1/16, I think), now they're expressed as $16.75
> or $16.33. (I don't think it goes finer than one cent.) This didn't
> used to be a big deal, but there have been a lot of advances in trading
> strategies and software that make it important now. If you have trading
> instruments like options and futures to use, and you think the market
> has valued a certain stock 2 cents too high or too low, you can make
> that bet and clear a lot of money in one day.
> 
> On the other hand, all those traders living in New York don't think an
> individual penny means anything. If they were late from work and saw a
> penny on the street, they probably won't stop to pick it up. So
> basically it depends on what you're measuring the money for in the
> first place.

It's important when there's large amounts of a price -- a million at
one cent is surely much different than a million at a cent-and-a-half.
 Fractional and decimal values are neccesary for some operations.

Also, traditionally, currency conversion is performed to the fourth
decimal, at least with the dollar.

Storing the currency along with the amount is important, too.
Supplying a current conversion table can be left as an excercise to
the reader, though.

 Some currencies eschew fractions entirely.  Some are not decimal. You
can't entirely get away with integers, though fixed-point precision is
a must for most financial calculations, and rational appropriate for
the rest. Floating-point inaccuracy is really annoying, and has
already bitten my in my financial app.