Re: Integers and Mathematical Correctness

[chl@clw.cs.man.ac.uk (Charles Lindsey)]

In <h8ZD7.46340$a14.5285167@news6-win.server.ntlworld.com> "chris.danx" <chris.danx@ntlworld.com> writes:


>Hi,

>To most this may seem insignificant but I'm more mathematically minded and I
>just found something out.  Many programming languages don't implement
>division properly!

>For example -3/2 should be -2 not -1, with a remainder 1 not -1.

Yes, the history of this goes back a long way, to ALGOL 60. The Europeans
(who were all mathematicians) were happy to define division for Reals and
were not particularly interested in integers. The Americans (who were all
programmers) saw a need for it, so the Europeans just said "OK, how do you
want to define it", and the Americans responded with the "obvious" and ONE
TRUE (i.e. FORTRAN) WAY.

Then, of course, hardware got to be built the "wrong" way. In every
subsequent programming language (ALGOL 68, Pascal, Ada) the language
designers knew perfectly well that they were designing it wrong, but dared
not make the change. I railed against this in 1983, and that is more or
less what I was told :-( .

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Charles H. Lindsey ---------At Home, doing my own thing------------------------
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