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From: john@frog.UUCP
Newsgroups: comp.lang.c
Subject: Re: Portable C vs Efficient C or "Cost of Portability"
Message-ID: <1316@frog.UUCP>
Date: Tue, 14-Apr-87 14:46:00 EST
Article-I.D.: frog.1316
Posted: Tue Apr 14 14:46:00 1987
Date-Received: Fri, 17-Apr-87 00:21:33 EST
References: <213@pyuxe.UUCP> <636@edge.UUCP>
Organization: Superfrog Heaven [ CRDS, Framingham MA ]
Lines: 36

> If you are more concerned about efficiency than about portability, then
> consider this:  There are 4 basic reasons for writing a particular program
> in C instead of in assembler:
>  a)  If efficiency is of little consequence -- the program is only going to
>      be run once or twice;
>  b)  If portability is important;
>  c)  If the programmer is ignorant of assembler; or
>  d)  If the boss wants "BIC lighter" programmers: cheap, disposable, and
>      easily replaceable.

You forgot

   e)  Reducing the opportunity for bugs by roughly a factor of 10.

Most estimates of the average number of bugs in a program indicate that the
number is roughly a constant fraction of the number of lines (which I believe
is typically 10%), independant of language.  A program written in C will
typically be 1/10 the size of an equivalent assembly program (depending on
the complexity of the C statements), so there are (roughly) 1/10 as many
thoughts to mis-think -- in assembly, they may go wrong on a less grand
scale, but they still are bugs.  I believe there was an article in the
most recent Comm. ACM about this general topic.

My favorite quote, which didn't arise from this consideration, but does
have the same philosophical bent:  "Presumably it was essential to get the
wrong answer as fast as possible."  Kernighan & Plauger, The Elements of
Programming Style.


--
John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101
...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA

"Happiness is the planet Earth
	in your rear-view mirror."
		- Sam Hurt, in "Eyebeam, Therefore I Am"