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From: bill@valiant (R.A.L Williams)
Newsgroups: comp.lang.ada
Subject: "Subtract C, add Ada"
Date: 31 Jan 1995 09:34:10 GMT
Organization: GEC-Marconi Research Centre
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Date: 1995-01-31T09:34:10+00:00
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In article <1995Jan23.154631.6702@sei.cmu.edu> you wrote:
: In article <3fo2ot$su2@miranda.gmrc.gecm.com> bill@valiant (R.A.L Williams) writes:

: I guess I'm about to show my ignorance of C, but I'm very confused
: bt this post.

: > 1. It allows your code to be more compact.

: >    NB DONT confuse compactness with poor layout! I find that, for example:
: >
: >       while ((c = getchar()) == ' ')
: >       {
: >          /* count spaces */
: >       }
: >
: >    is clearer than the 'expanded' alternative (to *me* :-).

: Nope, I find this totally unclear.  Who's counting?  Unless I've missed
: an invisible declaration, initialisation, and increment, the above
: code *doesn't* count spaces, it skips them.  And if that is its
: purpose, what's the point of the variable 'c'?  Why not just say

OK, I'm sorry, I didn't think I needed to spell things out in gratuitous
detail, so I just indicated the position and sort of code that might be
used by a comment. I haven't shown code that replaces spaces in an output
stream with text from the Koran either, sorry!

: Note also that if there are *no more* non space characters, the C code
: dies in an infinite loop, while the Ada code automatically does the
: right thing, namely raises the END_ERROR exception.

I'm afraid you *are* showing your ignorance of C. On each iteration of the
loop if the next input character is not a space (and this includes EOF)
then the loop terminates cleanly.

: >[example deleted]

: Again, I don't see it.  The Ada code makes it clear that *corresponding*
: elements of the array Q are being copied into P - though, of course,
: a real Ada programmer (TM) would have written just P := Q.  The C code
: doesn't make that clear - you're going to have to ferret out the
: initialisations of p and q to determine that.  And if you worry about
: the correctness of the copy - for instance, whether P and Q are the
: same size - that's surely going to be a lot easier to establish in Ada.

Again, a simplified example to illustrate a principle. The point is that
the less I have to move my eyes, or flip over pages, when reading/reviewing 
code, the more likely I am to understand it and find any bugs. You're
quite right, P := Q is an event more compact representation and I approve
(the Bill Williams official statement of approval!).

Bill Williams