bonomi at mail.r-bonomi.com
Sat Jan 14 09:51:02 UTC 2012
> From owner-freebsd-questions at freebsd.org Sat Jan 14 02:32:15 2012
> Date: Sat, 14 Jan 2012 09:28:21 +0100
> From: Polytropon <freebsd at edvax.de>
> To: Robert Bonomi <bonomi at mail.r-bonomi.com>
> Cc: freebsd-questions at freebsd.org
> Subject: Re: access(FULLPATH, xxx);
> On Sat, 14 Jan 2012 02:00:12 -0600 (CST), Robert Bonomi wrote:
> > To repeat some advice from one of my Computer Science professors, many years
> > ago, whenever I asked 'how does it work' questions: "Try it and find out."
> I bet my professor can beat up your professor. :-)
> Mine used to say several times: "Trial and error is NOT
> a programming concept!"
As far as writing applications goes, that is _somewhat_ correct.
However, 'trial and error' is _not_ the same thing as 'try it and find out'.
See the entire subject area of 'benchmarking'.
And, the only way to definitively establish if an alternate approach is
'better' -- i.e. 'faster', or 'smaller', or 'more efficient', etc. -- *IS*
to run a trial.
Your professor undoubtedly would not of approved when I wrote bubble-sort
code that _out-performed_ any other sorting technique -- up to the limits
of memory. Or when I re-wrote an application that used binary searches
of records, with a new version that used a brute-force linear search. I
thought I could 'do it better/faster' than the existing code, but the only
way to "definitively" find out was to 'try it'. And the 'trial' proved
out -- the replacement code was 'merely' somewhat over 100 times faster.
As far as 'doing it once' for the purpose of answering a 'how does it work'
question -- where one has _not_ read the documentation, *OR* the existing
documentation is _not_clear_, then simple experimentation -- to get *the*
authoritative answer -- is entirly justified.
When I got the 'try it and find out' advice, I was asking questions about
situations where the language _specification_ was unclear -- there were
two 'reasonable interpretations' of what the language inthe speciication
said, and I just wanted to know which one was the proper interpretation.
Now, given that the language in the specification _was_ abiguous and both
interpretations were reasonsble, different compiler builders could have
implemented differently, and 'try it and find out' was _necessary_ to
establish what that particular implementation did. <grin>
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