Re: Float to String

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

To the contrary, my friend.

One still must convert the floating-point binary number to decimal.
Binary-coded-decimal simply means that the decimal digits are
encoded with four bits each, but the decimal digits must be
computed just the same.

Furthermore, if the binary value is not converted to decimal with
the number of digits I specified earlier, precision is lost when
converting the decimal value back to binary for use in computation.

----- Original Message ----- 
From: "John B. Matthews" <nospam@nospam.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada-france.org>
Sent: November 08, 2004 6:40 PM
Subject: Re: Float to String


> In article 
> <mailman.85.1099945145.10401.comp.lang.ada@ada-france.org>,
> "David C. Hoos" <david.c.hoos.sr@ada95.com> wrote:
> 
> [...]
>> The problem in that case was that values stored in an Oracle database
>> when later extracted sometimes differed in the lsb.
>> 
>> What makes the problem similar is that Oracle required the data to be
>> stored in decimal format.  The problem with that is that decimal numbers
>> are not, in general, exactly representable in binary.  E.g. the decimal
>> number 0.1 is a non-terminating binary number.
> 
> Indeed. To guarantee portability among the 90-odd Oracle platforms, 
> they typically store numeric data using binary coded decimal (BCD) 
> with exponent. This neatly avoids the problem of binary-decimal 
> conversion.
> 
> Might the data type Interfaces.COBOL.Packed_Decimal (or something 
> similar) be a useful intermediate storage format?
> 
> -- 
> John
> ----
> jmatthews at wright dot edu
> www dot wright dot edu/~john.matthews/
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