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From: Nick Roberts <nickroberts@callnetuk.com>
Subject: Re: fixed type (delta) in ada
Date: 1999/11/28
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Date: 1999-11-28T00:00:00+00:00
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Nap wrote:
> 
> does anyone know why mutiplication between fixed type in ada produce a
> big round off error?
> ...

Do you want the short answer or the long answer, Nap?

The short version of the long answer is: the 'small' chosen for the type
'money' will be a power of two (e.g. 1/128); 0.20 will therefore not
have an exact representation when converted to the type 'money'; this
inexact representation of 0.20 will therefore produce an inexact result
after multiplication.

The short version of the short answer is: use a decimal type instead of
a fixed type (example follows).

   type Money is delta 0.01 digits 11;

Problem solved.

-- 
Nick Roberts
http://www.adapower.com/lab/adaos
Always call for the professionals. (If they don't help, call for me ;-)