Re: First-Time C

Re: First-Time C

[Robert I. Eachus]

In article <1993Jan11.210636.8396@gvl.unisys.com> garyp@rmtc.paramax.com (Gary 
Palangian [RMTC/ISP]) writes:

>       Our customer is probably going to make a decision to move from
>   Ada to C on my project...

   I find this statement very confusing...  There are some projects,
even very large projects, where progamming everything in Ada is
appropriate.  There are other projects, especially small projects,
where doing everything in C makes sense.  But I cannot imagine a
project where switching from all Ada to all C makes any sort of sense.
The most time and effort in an Ada project is in the design phase, the
most time and effort in a C project is usually spent in integration
and test.  Switching from Ada to C would seem to guarentee the worst
of both worlds.  (It would be nice if design in C, code and test in
Ada was the BEST of both worlds, but I don't think that free lunch
exists.)

>       I would appreciate concise and concrete information for
>  managing large systems development using C, especially from those
>  with an Ada background.

   Don't, use Ada instead!  (So much for concise and concrete. :-)

   If you need to do this for a large system, using Ada as a
compilable design language has a lot of advantages, but you must both
restrict the Ada used and maintain the design during the coding
process.  This works well but can cause personnel problems.  Everyone
ends up knowing both Ada and C if they didn't when the project
started, and from experience unwilling to work on another C project.
(Try spending a couple of years seeing all the advantages of Ada, but
none of the disadvantages, and vice-versa for C.  It's not fair, but
that's the way one project I know of that did this ended up.  This was
back in 1984-86, when no compilers supported the chapter 13 features
needed for a DBMS so it was a "right" decision.)

   The best of all possible worlds for your project, however, may be
to mix Ada and C.  Use Ada for the high-level design and structure,
and whenever appropriate write the (function) bodies in C.  This
allows you to use the strengths of both languages which are in very
different areas.  (You will also find that most of the bugs are in the
C code.  For the most part this will be because the parts where C is
most appropriate are the trickest routines to get right in any
case...)

    Have  fun,
--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...

Re: First-Time C

[Orville R. Weyrich]

In article <1993Jan11.210636.8396@gvl.unisys.com> garyp@rmtc.paramax.com (Gary 
Palangian [RMTC/ISP]) writes:
>
>    Our customer is probably going to make a decision to move from
>Ada to C on my project.  I am concerned about our ability to
>control the software engineering process, especially module integration,
>using C as a language.  Can anybody offer advice or a reference text
>that discusses large system development and the particular implementation
>and coordintation issues one should expect/plan for if C were the implementati
on
>language.

I learned [and taught Ada] before I learned [and taught C].

The ".h" files in C are pretty much like Ada package specifications,
and "static" is pretty much like "private".

Unfortunately, the C textbooks I deal with don't seem to have much sense
of programming in the large, and really do not give the sort of treatment
to how these features can be exploited as I would like.

Depending on the size of your project, it may be worth your while to acquire
or develop a tool to enforce certain standards, such as prohibiting any
global symbols from being present in a ".c" file that are not also in the
".h" file. Some compilers will warn you of such things, some not.
Make LINT a habit.

But if you are re-training Ada programmers to program in C, then you should
have a fairly easy time with this aspect. If you are using ANSI-C instead of
C++ you will probably miss things like overloading.

Hope this helps; I might think of more issues later.


orville

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Orville R. Weyrich, Jr.                           Weyrich Computer Consulting
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Re: First-Time C

[agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!cis.ohio-state.edu!ud]

In article <1993Jan11.210636.8396@gvl.unisys.com> garyp@rmtc.paramax.com (Gary 
Palangian [RMTC/ISP]) writes:
>Subject: First-Time C
>From: garyp@rmtc.paramax.com (Gary Palangian [RMTC/ISP])
>Date: Mon, 11 Jan 1993 21:06:36 GMT
>Hey Now Everybody,
>
>    I have been working with Ada for about 8 years now.  I think
>Ada is the best thing to happen to large systems development since
>magnetic disk.  Part of my previous job was comparing Ada and C so
>I know a little about C programming.  
>
>    Our customer is probably going to make a decision to move from
>Ada to C on my project.  I am concerned about our ability to
>control the software engineering process, especially module integration,
>using C as a language.  Can anybody offer advice or a reference text
>that discusses large system development and the particular implementation
>and coordintation issues one should expect/plan for if C were the implementati
on
>language.
>
>    Please, I don't wan't to start an Ada/C thing.  And I will not
>say any more about changing from Ada to C.  I would appreciate
>concise and concrete information for managing large systems development
>using C, especially from those with an Ada background.
>
>
>Thanks,
>
>
>Gary P.