[futurebasic] Re: [FB] FB^3 math accuracy

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From: Mel Patrick <mel@...>
Date: Wed, 22 Sep 1999 12:03:07 -0700
> > The BCD math in FB II could induce math errors in simple addition and
>> subtraction calculations. For example, my program works extensively with
>> dollar and cent calculations, but sometimes simple calculations would
>> incorrectly produce fractional cent results. Thus, I have to always use
>> extra steps to truncate or round results to eliminate incorrect
> > fractional cents.
>I was under the impression that, when working with currencies, the best way
>to preserve accuracy was to use integer math working with the smallest unit
>of the currency and then converting to the largest unit when displaying the

The ABS (American Banking System) used to use something akin to long 
ints for everything to do with the money stuff because of the 
accuracy. Any accounting software I ever worked on also used integers 
but for display, they shoved in the decimal so the human side of the 
equation wouldn't be confused.

For example $109.33, is one hundred nine dollars and 33 cents. But 
the .33 in computerese is 33/100 (a fraction that is infinite). So if 
you simply stored the number as 10933 and put in the decimal for 
display purposes only, there'd be a lot more accuracy and less hassle.

Just my .02 cents worth.

Mel Patrick