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From: diamond@diamond.csl.sony.junet (Norman Diamond)
Newsgroups: comp.lang.pascal
Subject: Re: C Ternary Conditional Expression?
Message-ID: <10296@socslgw.csl.sony.JUNET>
Date: 29 May 89 03:59:40 GMT
References: <950025@hpclcdb.HP.COM> <6490002@hplsla.HP.COM>
Sender: news@csl.sony.JUNET
Reply-To: diamond@csl.sony.junet (Norman Diamond)
Organization: Sony Computer Science Laboratory Inc., Tokyo, Japan
Lines: 54

In article <6490002@hplsla.HP.COM> davidr@hplsla.HP.COM (David M. Reed) writes:

>However, C programmers have continually reminded me how "efficient" 
>code can be written in C verses Pascal, such as
>    a[ (indx == last_indx) ? last_val : f(indx) ] = a [ y ];
>instead of
>
>    IF (indx = last_indx)
>       THEN temp := last_val
>       ELSE temp := f(indx);
>    a[temp] := a[y];

Actually the same could be done in Algol.  It is strange that C copied
that construct when no other language has done so.  Anyway it is ugly
and obfuscated.

>So why write in the terse C format? I personally think that
>    loop = loop + 1;
>is more clear than
>    loop += 1;

I don't like the <op>= forms because it's too easy to miss the <op>
when reading, but it really has an advantage when "loop" is really a
big long hairy expression.

>or the horrendous
>    loop++;

This is not so horrendous.  It is not too easy to miss "++".  In fact,
Brinch Hansen and other designers of Pascal dialects included generic
INC and DEC procedure calls to do such operations.

>And I despise things like
>
>    y = ++x;

Now we agree.  This manner of hiding side-effects is also ugly and
obfuscated.

Worst is:

    if (a=b) <some-statement>

This assigns b to a quite legally, and tests that value for non-zero,
but doesn't compare a to b.  Yup, C's philosophy is that programmers
know what they're doing, and that C programmers know every time they've
just made a typo, and that C programmers know they've forgotten every
other programming language they've ever used....

--
Norman Diamond, Sony Computer Science Lab (diamond%csl.sony.co.jp@relay.cs.net)
  The above opinions are my own.   |  Why are programmers criticized for
  If they're also your opinions,   |  re-implementing the wheel, when car
  you're infringing my copyright.  |  manufacturers are praised for it?