Re: Information Systems Annex (usefulness of Decimal Floats)

["Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca>]

Robert Dewar wrote:
> "Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca> wrote in message news:<3D5D1EA5.1040406@cogeco.ca>...
>>Robert Dewar wrote:
>>>"Robert C. Leif" <rleif@rleif.com> wrote in message news:<mailman.1029282844.28090.comp.lang.ada@ada.eu.org>...
>>
>>"Useless" is extreme. There are situations where decimal 
>>floating point is useful in computing financial values, 
>>but normally as intermediate results.
> 
> For intermediate results, decimal floating-point offers no
> particular advantages over binary floating-point. 

I disagree because binary floating point carries with it the
disadvantage of not being able to represent values
like 0.3 (it uses 0.299999 repeat), where a decimal floating
point does this precisely.

> Indeed
> the proposal carefully considered by CODASYL, but as far
> as I know not adopted, was to require the use of IEEE
> 64-bit binary floating-point arithmetic for calculation
> of intermediate results in COMPUTE.

I was speaking more generally about "computing financial
values" -- not strictly about COBOL.

> Note that in general the COBOL style is not to use COMPUTE
> but rather to carefully control the intermediate precision
> of each step, in which case floating-point offers very little advantage if any.

No disagreement there.
-- 
Warren W. Gay VE3WWG
http://home.cogeco.ca/~ve3wwg