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From: andyb@dartvax.UUCP (Andy Behrens)
Newsgroups: net.bizarre
Subject: Re: Bizarre Code
Message-ID: <3487@dartvax.UUCP>
Date: Thu, 15-Aug-85 10:45:13 EDT
Article-I.D.: dartvax.3487
Posted: Thu Aug 15 10:45:13 1985
Date-Received: Tue, 20-Aug-85 01:02:42 EDT
References: <462@moncol.UUCP>
Organization: Dartmouth College, Hanover, NH
Lines: 30

> What is the most bizarre line/piece of code you have seen in a production
> program?

I haven't seen it personally, but here's an example from Kernighan and 
Plauger's "Elements of Programming Style":

	DO 14 I = 1,N
	DO 14 J = 1,N
    14  V(I,J) = (I/J)*(J/I)

Their comment on this fragment is

	"A modest familiarity with Fortran tells us that this doubly
	nested DO loop assigns something to each element of an N by N
	matrix V.  What are the values assigned?  I and J are positive
	integer variables and, in Fortran, integer division truncates
	toward zero.  Thus when I is less than J, (I/J) is zero;
	conversely, when J is less than I, (J/I) is zero.  When I
	equals J, both factors are one. So (I/J)*(J/I) is one if and
	only if I equals J; otherwise it is zero.  The program fragment
	puts ones on the diagonal of V and zeros everywhere else.  (V
	becomes an identity matrix.)  How clever!

	"Or is it?"

					Andy Behrens

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