Question about checks for min and max values

[Jay R. Ashworth]

On Mon, Jul 25, 2005 at 02:10:08PM -0400, Kenneth Brody wrote:
> > Perhaps she did.  But BASIC, Fortran, COBOL--and, in truth, C--all
> > predate any version of Profile that *had* processing, so far as I know.
> 
> How do those languages represent a number without any value?

To the best of my knowledge and belief, none of them admit of the
concept of "a number without any value".  A "numeric variable to which
no other value has been assigned", a different thing entirely, returns
"0".

> > And they all stole their definitions of "is equal to" from
> > *mathematics*, which sort of predates all of them.
> >
> > By a few hundred years.
> 
> Does mathematics have a representation for a number without any value?
> (We're talking _numbers_, not number _sets_.)

A number cannot *not* have a value, by definition.  Only a variable can
have no value.

But this is all orthogonal to my central thesis:

> And didn't someone point out that "="/"eq" is really "equivalent" and
> not "identical"?  (Remember, "0.0" is not identical to "0.00".)

Yes, Nancy; and both Mark and I disagree with her implication that
that's an acceptable thing to expect programmers to figure out/remember.

And, actually, though "identical" is a question-begging term, 0.0 does
equal 0.00, numerically: the extra degree of precision is not germane
to the *mathematical* aspect of those numbers, but more their
statistical interpretation. 

How those two strings convert to internal numeric representations on a
given combination of processor, language, compiler, and libraries is
yet another, also orthogonal question.

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra at baylink.com
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