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From: bs@linus.UUCP
Newsgroups: comp.lang.c
Subject: Re: Float Comparisons in C
Message-ID: <935@linus.UUCP>
Date: Fri, 20-Mar-87 13:26:51 EST
Article-I.D.: linus.935
Posted: Fri Mar 20 13:26:51 1987
Date-Received: Sun, 22-Mar-87 19:37:33 EST
References: <5054@brl-adm.ARPA>
Reply-To: bs@linus.UUCP (Robert D. Silverman)
Organization: The MITRE Corporation, Bedford MA
Lines: 23

In article <5054@brl-adm.ARPA> Beebe@utah-science.arpa (Nelson H.F. Beebe) writes:
>In mathematical software, there are perfectly valid grounds
 
etc.
>(a + b + c) with (a + c + b) (f.p. arithmetic does not obey
>the distributive law of addition), or for equality of
 
A little nitpicking here: there is no distributive law of addition.
What the auther means here is the associative law:

(a + (b+c)) != ((a + b) + c)

The comutative law IS obeyed:

a + b = b + a.

In the example above the author has essentially said:

( (a + b) + c) != (a + (b+c))  because

(a + (b+c)) does equal (a + (c+b))

Bob Silverman