Kindness

Kindness

[Mark Lundquist]

I hate to see people get trashed on for asking an innocent question!

A while back, a guy posted to this group with a question about how to do
something (or not do it) in Ada. One respondent, a respected expert in
the Ada community, replied with a post that was pretty thoroughly
contemptuous and condescending.

I don't get it!  The guy asking the question was willing to expose his
ignorance, and he put the question clearly and courteously.  So why the
insults?  I felt bad for the guy who asked the question and embarassed
by this response.  Also, it was a great opportunity to point out some of
the clear advantages of Ada, but it went to waste 'cause now that guy
will probably go away thinking of Ada as the Language Of Buttheads.

Re: Kindness

[Marin David Condic]

Mark Lundquist wrote:

> I hate to see people get trashed on for asking an innocent question!
>

This is a bit of a non-sequiter. There are often rude posts to this (and
other) newsgroups - sometimes justified, sometimes not. A specific example
may be in order - unless there is some desire not to hold up otherwise
respected members of the community to public rebuke.

Things that smell of students trying to get there homework done for them
generally deserve some sort of "rude" scolding. Questions from the merely
ignorant should be treated with patience, understanding and a bit of
humility. (There was a time *we* were new at it too and asked questions that
seemed obvious to others.) I think it is useful to look at such questions as
an opportunity to help others and give back some of what we've been given -
not as opportunities to show off how smart we are or to massage our own egos
by tearing down others.

MDC
--
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
***To reply, remove "bogon" from the domain name.***

Visit my web page at: http://www.mcondic.com/

Re: Kindness

[Geoff Bull]

Marin David Condic wrote:
> 
>Things that smell of students trying to get there homework
>done for them generally deserve some sort of "rude" scolding. 

I think you're all being a bit precious.
Getting some help via the net is just another part of
the educational experience.

Lighten up!

Geoff

Re: Kindness

[Robert Dewar]

In article <37CF0FE0.2B299477@acenet.com.au>,
  Geoff Bull <gbull@acenet.com.au> wrote:
> I think you're all being a bit precious.
> Getting some help via the net is just another part of
> the educational experience.

Getting help is one thing, asking the net to do your homework
or copying your homework from the net is quite another (we had
several students at NYU last semester who got into severe
trouble doing this, and that seems quite appropriate to me).

There is a big difference between:

"has anyone got a program that solves the 8-queens problem
 with graphical output to the screen".

and

"I have to do an 8-queens program with graphical output to
the screen for a homework assignment. Can anyone point me in
the right direction for a simple graphics package usable from
Ada that would be appropriate to this problem?"

The former is unacceptable. The latter message is a constructive
attempt to learn the best way of solving the assignment, and is
indeed entirely appropriate. Furthermore, I can think of many
occasions on which questions of the second type posted here
have elicited useful answers!

Anyone who thinks that concern over students cheating and not
doing the work they need to do learn is "precious" is missing
a pretty important point!

Robert Dewar
Professor of Computer Science
New York University

(my academic affiliation seems more appropriate for this
particular post :-)



Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[Aidan Skinner]

On Fri, 03 Sep 1999 15:10:41 GMT, Robert Dewar
<robert_dewar@my-deja.com> wrote: 

>several students at NYU last semester who got into severe
>trouble doing this, and that seems quite appropriate to me).

Apparently this year has been especially bad for it, all of the
"ancient" Scottish Universities (Glasgow, Aberdeen, Edinburgh and St
Andrews) had problems with this, half of one of Edinburgh's first year
CS course was under investigation at one point. 

I think it's awful that this is causing some people (journalists
mostly) to complain that the net is letting people get access to
information too easily, but it's equally awful that this is happening.

Disclaimer: I'm a 2nd yr Computing Science student at the University
of Glasgow[1]

- Aidan 

[1] Would be 3rd year, but I'm repeating a year due to depression :/
-- 
http://www.skinner.demon.co.uk/aidan/
http://www.gla.ac.uk/Clubs/WebSoc/~9704075s/
What evil shall I do today?

Re: Kindness

[Marin David Condic]

Aidan Skinner wrote:

> Apparently this year has been especially bad for it, all of the
> "ancient" Scottish Universities (Glasgow, Aberdeen, Edinburgh and St
> Andrews) had problems with this, half of one of Edinburgh's first year
> CS course was under investigation at one point.
>

The bad news is that as this sort of thing gets perceived to be widespread
and rampant, the value of a good grade goes down. You can say you
graduated from Glasgow in CS with a 4.0 average and folks outside the
school will think "Yeah, but so what? Most of the fresh-outs from there
got their homework from the Internet, so its easy to get a 4.0" Hence the
innocent are dragged down with the guilty.

MDC
--
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
***To reply, remove "bogon" from the domain name.***

Visit my web page at: http://www.mcondic.com/

Re: Kindness

[Bill Findlay]

In article <37D04424.16486E1E@pwfl.com>,Marin David Condic wrote:

> The bad news is that as this sort of thing gets perceived to be widespread
> and rampant, the value of a good grade goes down. You can say you
> graduated from Glasgow in CS with a 4.0 average and folks outside the
> school will think "Yeah, but so what? Most of the fresh-outs from there
> got their homework from the Internet, so its easy to get a 4.0" Hence the
> innocent are dragged down with the guilty.
> 
No one with an average of 4.0 would have the slightest hope of graduating. 8-)

-- 
Bill Findlay
Department of Computing Science
The University of Glasgow

Re: Kindness

[Robert Dewar]

In article <wf-0609991819090001@wyre.dcs.gla.ac.uk>,
  wf@dcs.gla.ac.uk (Bill Findlay) wrote:
> In article <37D04424.16486E1E@pwfl.com>,Marin David Condic
wrote:
>
> > The bad news is that as this sort of thing gets perceived to
be widespread
> > and rampant, the value of a good grade goes down. You can
say you
> > graduated from Glasgow in CS with a 4.0 average and folks
outside the
> > school will think "Yeah, but so what? Most of the fresh-outs
from there
> > got their homework from the Internet, so its easy to get a
4.0" Hence the
> > innocent are dragged down with the guilty.
> >
> No one with an average of 4.0 would have the slightest hope of
graduating. 8-)


I actually find that students don't help themselves OR their
grades by copying on assignmments. What happens is that they
don't learn as they should from the assignments, and then they
blow the exams completely.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[Marin David Condic]

Bill Findlay wrote:

> No one with an average of 4.0 would have the slightest hope of graduating. 8-)

Excuse my ignorance. Is the grading system over there very much different than
that which most American schools use? A = 4.0, B = 3.0, etc.? Or am I simply
missing the joke? (Things don't always translate well over the net! :-)

MDC
--
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
***To reply, remove "bogon" from the domain name.***

Visit my web page at: http://www.mcondic.com/

Re: Kindness

[Bill Findlay]

In article <37D50512.F23F9F68@pwfl.com>, e108678@pwflcom wrote:

> Bill Findlay wrote:
> 
> > No one with an average of 4.0 would have the slightest
> > hope of graduating. 8-)
> 
> Excuse my ignorance. Is the grading system over there very much different than
> that which most American schools use? A = 4.0, B = 3.0, etc.?
> 

Things are quite different.
For a start, we think of 'schools' as places of primary or
secondary education, full of unruly schoolchildren, and we do rather
insist on being a grown-up university. 8-)

In our systems of measurement a bald 4.0 could only be either 4%, or a
(new-fangled) Grade Point/Average which for our courses ranges up to 16,
making 4.0 very much a failure in either case. To get *into* our
graduating courses, you should expect to get a GPA of 12 in earlier years.
But that is just our system. Universities in the UK tend to be rather idiosyncratic, and many use quite different numbers for the same levels
of attainment. In fact, even within this department a totally different
and more traditional system is used for grading Honours degrees
(1st-, upper 2nd-, lower 2nd-, or 3rd- class).

> Or am I simply missing the joke?
> (Things don't always translate well over the net! :-)
>

It's not so much the Net as that old business of being divided
by a common language, perhaps (English, not Ada 95!).

-- 
Bill Findlay
Department of Computing Science
The University of Glasgow

Re: Kindness

[Larry Kilgallen]

In article <slrn7t0bmv.4bf.aidan@skinner.demon.co.uk>, aidan@skinner.demon.co.uk (Aidan Skinner) writes:

> I think it's awful that this is causing some people (journalists
> mostly) to complain that the net is letting people get access to
> information too easily, but it's equally awful that this is happening.

Of course in a situation where technological limits make cheating
impossible, nobody is learning ethics from the experience.

In life, there will not always be technological limits.

Larry Kilgallen

Re: Kindness

[Aidan Skinner]

On Fri, 3 Sep 1999 23:18:53 GMT, Larry Kilgallen
<kilgallen@eisner.decus.org> wrote: 

>Of course in a situation where technological limits make cheating
>impossible, nobody is learning ethics from the experience.

Yeah, depressing isn't it?

As an attempt to get vaugely back on topic, Glasgow CS dept has a
program that attempts to detect cheating which is written
in... Ada. :)

I don't know if it's publicly available or not though.

- Aidan
-- 
http://www.skinner.demon.co.uk/aidan/
http://www.gla.ac.uk/Clubs/WebSoc/~9704075s/
What evil shall I do today?

Re: Kindness

[Geoff Bull]

Robert Dewar wrote:
> 
> In article <37CF0FE0.2B299477@acenet.com.au>,
>   Geoff Bull <gbull@acenet.com.au> wrote:
> > I think you're all being a bit precious.
> > Getting some help via the net is just another part of
> > the educational experience.
> 
> Getting help is one thing, asking the net to do your homework
> or copying your homework from the net is quite another 

Yes, I agree with this. And I'm quite removed from undergraduate
situation, so I would really have no idea what goes on in
universities these days. 


> 
> Anyone who thinks that concern over students cheating and not
> doing the work they need to do learn is "precious" is missing
> a pretty important point!
> 

An important point for me is that rudeness is NEVER acceptable.
(even though I can hand a good deal of it myself, inadvertantly
and advertantly!)

It is very easy not to answer a homework (or any other) question.
Why do people feel the necessity to be rude?
A rude response certainly diminishes my opinion of the sender,
no matter what the question.

Geoff

Re: Kindness

[Aidan Skinner]

On Mon, 06 Sep 1999 00:10:50 +1000, Geoff Bull <gbull@acenet.com.au> wrote:

>An important point for me is that rudeness is NEVER acceptable.
>(even though I can hand a good deal of it myself, inadvertantly

True, although I've yet to see the same level of rudeness here that
occurs in other newsgroups (even some of the more "civilised" places
like uk.net.config, sci.crypt can get *very* vicious at
times). There's practically none of the ad hominem attacks, personal
fights and out and out flame wars that characterise usenet these
days[1][2]. 

- Aidan

[1] When I were a lad... ;)
[2] Death of the net imminent, film at 11.
-- 
http://www.skinner.demon.co.uk/aidan/
http://www.gla.ac.uk/Clubs/WebSoc/~9704075s/
What evil shall I do today?

Re: Kindness

[Marin David Condic]

Geoff Bull wrote:

> Marin David Condic wrote:
> >
> >Things that smell of students trying to get there homework
> >done for them generally deserve some sort of "rude" scolding.
>
> I think you're all being a bit precious.

"Precious"??? That doesn't translate well. :-) Makes me think I'm a
veritable gold mine of wisdom.

>
> Getting some help via the net is just another part of
> the educational experience.
>

I guess the traditional way of housebreaking a dog is to catch it when
it pees on the carpet, stick its nose in it and swat it with a newspaper
while expressing firm displeasure. Maybe we could view peeing on the
carpet as just another part of the dog's educational experience. One
method produces a housebroken dog. The other method produces an
untrained, undomesticated, unmanageable, wild animal - and a house that
smells bad. :-)

"Help" is one thing. "Do my homework for me" is another thing
altogether.

>
> Lighten up!
>

Given that we don't have an actual case in front of us, perhaps we are
taking it a bit too seriously. But I think that the education of the
next generation of people who will be running the world when I retire is
a pretty important mission. Letting students think that academic fraud,
intellectual dishonesty, theft and other assorted high crimes and
misdemeanors are all just "part of the game" and are not "wrong" so long
as you can get away with it is probably a bad idea. It breeds the notion
that lying and cheating in other areas of life is O.K. - depending on
what the definition of "is" is!

>
> Geoff

MDC
--
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
***To reply, remove "bogon" from the domain name.***

Visit my web page at: http://www.mcondic.com/

Re: Kindness

[Larry Kilgallen]

In article <37CFF7DC.CFF9717C@pwfl.com>, Marin David Condic <condicma@bogon.pwfl.com> writes:

> Given that we don't have an actual case in front of us, perhaps we are
> taking it a bit too seriously. But I think that the education of the
> next generation of people who will be running the world when I retire is
> a pretty important mission. Letting students think that academic fraud,
> intellectual dishonesty, theft and other assorted high crimes and
> misdemeanors are all just "part of the game" and are not "wrong" so long
> as you can get away with it is probably a bad idea. It breeds the notion
> that lying and cheating in other areas of life is O.K. - depending on
> what the definition of "is" is!

Another group I read has a contest going (obviously known to those who
really follow the group) for the most creative non-answer to homework
problems.  Something that goes into great detail but cannot possibly
be true is the ideal.

Larry Kilgallen

Re: Kindness

[Robert I. Eachus]

Larry Kilgallen wrote:
  
> Another group I read has a contest going (obviously known to those who
> really follow the group) for the most creative non-answer to homework
> problems.  Something that goes into great detail but cannot possibly
> be true is the ideal.
 
    I prefer a perfectly correct answer (not the one intended by the
instructor of course), that references material that the student may not
encounter for years.  For example, I could program the eight queens
problem with eight interacting tasks as a demonstration of rendesvous. 
(Nico Lomuto wrote a neat eight queens program years ago which generated
a new set of tasks for possible position in the next row.  I wonder if
there are now machines that can run it.)

-- 

                                        Robert I. Eachus

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

Eight Queens problem (was Re: Kindness)

[Daryle Walker]

In article <37D02CC0.BEF1BC69@mitre.org>, "Robert I. Eachus"
<eachus@mitre.org> wrote:

>Larry Kilgallen wrote:
>  
>> Another group I read has a contest going (obviously known to those who
>> really follow the group) for the most creative non-answer to homework
>> problems.  Something that goes into great detail but cannot possibly
>> be true is the ideal.
> 
>    I prefer a perfectly correct answer (not the one intended by the
>instructor of course), that references material that the student may not
>encounter for years.  For example, I could program the eight queens
>problem with eight interacting tasks as a demonstration of rendesvous. 
>(Nico Lomuto wrote a neat eight queens program years ago which generated
>a new set of tasks for possible position in the next row.  I wonder if
>there are now machines that can run it.)

What is this Eight Queens Problem?  I've heard of it only in passing; I
never had to do it as an assignment (BTW, I've been out of school for 2
years).  I'm guessing it's how to place eight queen chess pieces on a
chess board without any of them threatening another.  Where can I find
more information about it?  What is Nico Lomuto's Ada-task solution?

[For those who haven't heard of chess, a chess board has a grid of 64
squares in a 8-by-8 square.  A queen piece can attack any enemy piece that
can be directly intercepted via a row, column, or 45-degree diagonal.]

[Just from a minimal description, I can guess a solution:
   1. Put a queen on a random square
   2. Mark the queen's square, squares on the same row and column,
      and squares diagonally connected, invalid
   3. Repeat the previous steps for the next 7 queens
      (using valid squares only, of course)
 I got the feeling that there's some gotchas to this newbie approach,
 like all good CS problems have.]

-- 
Daryle Walker
Video Game, Mac, and Internet Junkie
walke751 AT concentric DOT net

Re: Eight Queens problem (was Re: Kindness)

[Robert Dewar]

In article
<walke751-0409992215490001@ts001d42.nor-ct.concentric.net>,
  walke751@concentric.net.invalid (Daryle Walker) wrote:
> [Just from a minimal description, I can guess a solution:
>    1. Put a queen on a random square
>    2. Mark the queen's square, squares on the same row and
column,
>       and squares diagonally connected, invalid
>    3. Repeat the previous steps for the next 7 queens
>       (using valid squares only, of course)
>  I got the feeling that there's some gotchas to this newbie
approach,
>  like all good CS problems have.]


You will find it very instructive to try using the above
algorithm by hand.

What you will find is that step 1 is wrong, it makes a
difference *which* square you choose. You can get stuck
if you make wrong choices.

What you need here is sometimes called "angelic
non-determinism", i.e. make the "right" choice by
some magic method.

Well there is no magic in real life, so the normal
implementation of AD is to make an arbitrary choice, and
then if you get stuck later, go back and change it. This
is called "back tracking", and basicaly the 8-queens
problem is precisely an excercise in back tracking.

It is instructive, but not trivial, to try to work out
how to do this yourself :-)


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[Robert I. Eachus]

Robert Dewar wrote:
 
> Well there is no magic in real life, so the normal
> implementation of AD is to make an arbitrary choice, and
> then if you get stuck later, go back and change it. This
> is called "back tracking", and basicaly the 8-queens
> problem is precisely an excercise in back tracking.
 
    The method used by Nico Lomuto's solution was to create a task for
each possible placement at each level, and the first task that
corresponded to a correct solution would stop the creation of new tasks
and cause all the waiting tasks, whether part of an incorrect or correct
solution, to terminate.  The problem is that doing this requires lots of
tasks, I believe Nico's program potentially created 8! (40,320) of
them.  Since Nico's program was written to show a clever use of the
terminate alternative it wouldn't run correctly even on systems that
waited during task creation for a task descriptor to become free--all
tasks waited for a solution to be found.

    Ah, the advantage of being a pack rat.  The original article was in
Ada Letters March-April 1983 pages II-5.62-75.  I think that the
application to the Eight Queens problem was published later as a
concrete example of the paper, but it would probably be much easier to
reconstruct it than find it.

-- 

                                        Robert I. Eachus

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

Re: Eight Queens problem (was Re: Kindness)

[Vladimir Olensky]

Daryle Walker wrote in message ...
>In article <37D02CC0.BEF1BC69@mitre.org>, "Robert I. Eachus"
><eachus@mitre.org> wrote:
>
>
>What is this Eight Queens Problem?  I've heard of it only in passing; I
>never had to do it as an assignment (BTW, I've been out of school for 2
>years).  I'm guessing it's how to place eight queen chess pieces on a
>chess board without any of them threatening another.  Where can I find
>more information about it?  What is Nico Lomuto's Ada-task solution?
>
>[For those who haven't heard of chess, a chess board has a grid of 64
>squares in a 8-by-8 square.  A queen piece can attack any enemy piece that
>can be directly intercepted via a row, column, or 45-degree diagonal.]
>
>[Just from a minimal description, I can guess a solution:
>   1. Put a queen on a random square
>   2. Mark the queen's square, squares on the same row and column,
>      and squares diagonally connected, invalid
>   3. Repeat the previous steps for the next 7 queens
>      (using valid squares only, of course)
> I got the feeling that there's some gotchas to this newbie approach,
> like all good CS problems have.]


Eight Queens Problem and  was discussed and illustrated
in "Programming in Modula-2" written by Niklaus Wirth.
There were several editions of this book. Third edition was
published by Springer-Verlag in 1985.
This book may be  useful not only for those using Modula-2  but
also for those  learning  Ada.

Regards.

Re: Eight Queens problem (was Re: Kindness)

[Robert Dewar]

In article <rt872lon8os47@corp.supernews.com>,
  "Vladimir Olensky" <vladimir_olensky@yahoo.com> wrote:
> Eight Queens Problem and  was discussed and illustrated
> in "Programming in Modula-2" written by Niklaus Wirth.
> There were several editions of this book. Third edition was
> published by Springer-Verlag in 1985.
> This book may be  useful not only for those using Modula-2
but
> also for those  learning  Ada.


I am sure that Vladimir knows this, but just to avoid any
confusion, this problem is much older than 1985. The reference
to the NW book is simply one of many discussions of this well
known problem (well known because it is the canonical
example, one might say

8 queens is to backtracking as
factorial is to recursion

:-)


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[bourguet]

In article <7r1c4c$9an$1@nnrp1.deja.com>,
  Robert Dewar <robert_dewar@my-deja.com> wrote:
> [...] one might say
>
> 8 queens is to backtracking as
> factorial is to recursion
>
> :-)

Do you want to say it is the canonical example of use or it is an as
good example: there is another way to solve the problem which usually
come first to mind?

I've never had problem with recursion, but for factorial except when
writing in a functionnal language I'll use iteration over recursion.

-- Jean-Marc


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[Robert Dewar]

In article <7r2fc6$1sc$1@nnrp1.deja.com>,
  bourguet@my-deja.com wrote:
> Do you want to say it is the canonical example of use or it is
an as
> good example: there is another way to solve the problem which
usually
> come first to mind?

Nothing so complicated, just that, as factorial is typically
used in a text book to illustrate recursion, 8Q is used to
illustrate backtracking.

I agree that simple tail recursion is a horrible example for
motivating recursion. Here is the example I always use, with
a little driver:

with Text_IO; use Text_IO;
procedure p is
   procedure Print_Int (I : Natural) is
   begin
      if I >= 10 then
         Print_Int (I / 10);
      end if;
      Put (Character'Val (Character'Pos ('0') + I mod 10));
   end Print_Int;
begin
   Print_Int (12435);
end;

The nice thing about this is that it does simply something
which is annoyingly fiddly to do iteratively. In particular,
you have to worry about the maximum number of digits which
simply does not arise. The point is made even more strongly
in a language which does not have nasty artificial limits on
the size of integers as in C or Ada or Java :-)

Robert Dewar


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[bourguet]

In article <7r4edb$gg2$1@nnrp1.deja.com>,
  Robert Dewar <robert_dewar@my-deja.com> wrote:
> In article <7r2fc6$1sc$1@nnrp1.deja.com>,
>   bourguet@my-deja.com wrote:
> > Do you want to say it is the canonical example of use or it is
> an as
> > good example: there is another way to solve the problem which
> usually
> > come first to mind?
>
> Nothing so complicated, just that, as factorial is typically
> used in a text book to illustrate recursion, 8Q is used to
> illustrate backtracking.
>
> I agree that simple tail recursion is a horrible example for
> motivating recursion.

Is the classical way of writing the factorial

function fact(n : natural) return natural is
begin
   if n = 0 then
      return 1;
   else
      return n*fact(n-1);
   end if;
end fact;

tail recursive? There is a multiplication to be executed after the
return. Writing a tail recursive version is a little more complicated
and is an interesting thing to do. But obviously you are then even
nearer of the iterated version.

> Here is the example I always use, with a little driver:
[recursive version of print_int]
Indeed this is more interesting than factorial for introducing
recursion.

-- Jean-Marc


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[Robert Dewar]

In article <7r50tj$sp3$1@nnrp1.deja.com>,
  bourguet@my-deja.com wrote:
> function fact(n : natural) return natural is
> begin
>    if n = 0 then
>       return 1;
>    else
>       return n*fact(n-1);
>    end if;
> end fact;
>
> tail recursive? There is a multiplication to be executed after
> the return.

You are right, it is not tail recursive as normally expressed,
however the transformation here to a tail recursive version is
a standard one (and one that is for example performed by many
compilers).

The real point is that you want to choose something which shows
that recursion is useful, not merely a neat way of writing a
simple loop in a kludgy manner, which will be quite inefficient
if the compiler does NOT do pretty clever tail recursion
elimination. I would not expect ANY Ada compiler to be that
clever, and in fact, it would not surprise me to find that
many Ada compilers do no tail recursion elimination at all.

P.S. It is interesting how important this optimization can be.
The Realia COBOL compiler does extensive tail recursion
elimination (on the x86, in its simplest form, this consists
of replacing a CALL x/RET sequence by JMP X), and it turned
out to be a VERY important optimization. That sounds very
strange, given that COBOL does not allow recursion, but of
course general tail recursion elimination also catches the
case of calling some *other* procedure as the last step.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Eight Queens problem (was Re: Kindness)

[Ted Dennison]

In article <7r5mjn$c72$1@nnrp1.deja.com>,
  Robert Dewar <robert_dewar@my-deja.com> wrote:
> if the compiler does NOT do pretty clever tail recursion
> elimination. I would not expect ANY Ada compiler to be that
> clever, and in fact, it would not surprise me to find that
> many Ada compilers do no tail recursion elimination at all.

FYI: The GreenHills Ada 95 compiler does have an option for tail
recursion elimination. The description implies it won't try to transform
a routine into tail-recursive form, though.

When last I checked ObjectAda did not perform this optimization.

--
T.E.D.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[tmoran]

The root post of this thread did not mention homework.  Since it
was posted at the very start of September it seems unlikely it
was referring to a homework question.  Was there a recent
homework question on c.l.a?  Or was the root post not referring
to a "do my assignment" homework question?

Re: Kindness

[Marin David Condic]

tmoran@bix.com wrote:

> The root post of this thread did not mention homework.  Since it
> was posted at the very start of September it seems unlikely it
> was referring to a homework question.  Was there a recent
> homework question on c.l.a?  Or was the root post not referring
> to a "do my assignment" homework question?

I think the reason that homework got brought up in general was as the
only time it might be considered fair/reasonable to be "rude" in
responding to the questions that come from the uninitiate.

Given that there was no specific instance illustrating a condescending
or rude reply in the original post, its kind of natural for the thread
to drift. I think we all agree that Ada is best served by having her
user community be as friendly and helpful to the newbies as possible.
Requests by newbies that we do their homework for them being in my mind
at least, the only occasion for violating that rule.

MDC
--
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
***To reply, remove "bogon" from the domain name.***

Visit my web page at: http://www.mcondic.com/

Re: Homework (was Re: Kindness)

[Larry Kilgallen]

In article <37D55622.69B27515@rational.com>, Mark Lundquist <mark@rational.com> writes:

> Larry Kilgallen wrote:
> <BLOCKQUOTE TYPE=CITE>

No, Larry Kilgallen never wrote HTML to this newsgroup :-)

Re: Homework (was Re: Kindness)

[Ted Dennison]

In article <1999Sep7.155434.1@eisner>,
  Kilgallen@eisner.decus.org.nospam wrote:
> In article <37D55622.69B27515@rational.com>, Mark Lundquist
<mark@rational.com> writes:
>
> > Larry Kilgallen wrote:
> > <BLOCKQUOTE TYPE=CITE>
>
> No, Larry Kilgallen never wrote HTML to this newsgroup :-)
>

Good thing too, as those of us who use text-based newsreaders or deja
would have been quite annoyed. :-)

--
T.E.D.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Homework

[Mark Lundquist]

Ooops... OK, OK, sorry about the HTML!  :-)  Here it is again in ascii,
I'll cross my fingers and hope this works...

Larry Kilgallen wrote:

   Another group I read has a contest going (obviously known to those
who
   really follow the group) for the most creative non-answer to homework

   problems.  Something that goes into great detail but cannot possibly
   be true is the ideal.

   Larry Kilgallen


  The best one I've ever seen was in this group -- or maybe on
team-ada@acm.org.  The "student" had
  requested full source code for a program to play tic-tac-toe (or
something like that) on the grounds
  that he could not be bothered to do the homework assigments since he
already knew all the stuff, and in
  any case he couldn't afford the time since he was working at a
full-time job.

  The answer was:

      with Ada.Text_Io;
      procedure Tic_Tac_Toe is
      begin
          Ada.Text_Io.Put_Line ("You lose.");
      end Tic_Tac_Toe;

Re: Kindness

[Larry Kilgallen]

In article <37CC6844.AB898EEE@rational.com>, Mark Lundquist <mark@rational.com> writes:
> I hate to see people get trashed on for asking an innocent question!
> 
> A while back, a guy posted to this group with a question about how to do
> something (or not do it) in Ada. One respondent, a respected expert in
> the Ada community, replied with a post that was pretty thoroughly
> contemptuous and condescending.

Absent a specific example, one cannot be certain.

One possible reason would be that the post appeared to be someone who
was attempting to do "homework via newsgroups".  This annoys two classes
of people:

	1) Instructors who expect students to do their own work

	2) Former students who did their own work back in the good old days

At least once in this group the instructor who noticed the post was
actually the instructor who had assigned that problem to that student.

> by this response.  Also, it was a great opportunity to point out some of
> the clear advantages of Ada, but it went to waste 'cause now that guy
> will probably go away thinking of Ada as the Language Of Buttheads.

There are some who do not want to attract to the Ada community those
who would pass someone else's work off as their own, or particularly
someone who would acquire academic credentials without really understanding
the material.  You would not want to end up maintaining something that
person had written.

But as I said, absent a specific example, one cannot be certain.
The case you are considering might have had no hint of being a
homework problem.

Larry Kilgallen

Re: Kindness

[Robert Dewar]

In article <1999Sep2.074353.1@eisner>,
  Kilgallen@eisner.decus.org.nospam wrote:
> One possible reason would be that the post appeared to be
someone who
> was attempting to do "homework via newsgroups".  This annoys
two classes
> of people:
>
> 	1) Instructors who expect students to do their own work
>
> 	2) Former students who did their own work back in the
>          good old days
>
> At least once in this group the instructor who noticed the
> post was actually the instructor who had assigned that problem
> to that student.

Actually for me this misses the point, sure you may annoy the
above two classes of people, but the important thing is that
you are being very unfair to the student in this case, since
it is very damaging for students to get in the habit of letting
others do their work. They may not realize it at the time, but
later on, they will regret it, and it is not a good idea to be
an accomplice in this sequence of events :-)

That being said, you can often suggest something that will help
the student help themselves, and then everyone wins.

Robert De



Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[Andy Askey]

I haven't followed all the posts in this thread, but I just can't help
but put in my opinion here.

Suppose the poster was a student attempting to get the answer to some
assigned question.  So what?  What is the difference if a student reads
the answer in a book, a man page, or from a newsgroup?  The goal of the
student (and the teacher, I hope) is that the student learns from the
homework.  One thing I find lacking in the education system of today is
that it does not prepare a graduate for the working world.  Once a
student becomes a member of some Software Engineering department, he/she
will loose points for wasting time figuring out something that is
available by questioning an experience coworker.  Part of the
educational process should be to teach how to complete a task in the
most efficient manner.  No one ever got a promoting rediscovering
something that is common knowledge through the industry.  But plenty
succeed by applying the knowledge of others to develop new ideas.

-- 
---------------------------------------------------
|                 Andy Askey                      |
|              Software Engineer                  |
|           Raytheon Systems Company              |
|   670 Discovery Drive, Huntsville, AL  35806    |
|   Phone: (256) 971-2367  Fax: (256) 971-2306    |
|        andrew_j_askey@res.raytheon.com          |
---------------------------------------------------
Robert Dewar wrote:
> 
> In article <1999Sep2.074353.1@eisner>,
>   Kilgallen@eisner.decus.org.nospam wrote:
> > One possible reason would be that the post appeared to be
> someone who
> > was attempting to do "homework via newsgroups".  This annoys
> two classes
> > of people:
> >
> >       1) Instructors who expect students to do their own work
> >
> >       2) Former students who did their own work back in the
> >          good old days
> >
> > At least once in this group the instructor who noticed the
> > post was actually the instructor who had assigned that problem
> > to that student.
> 
> Actually for me this misses the point, sure you may annoy the
> above two classes of people, but the important thing is that
> you are being very unfair to the student in this case, since
> it is very damaging for students to get in the habit of letting
> others do their work. They may not realize it at the time, but
> later on, they will regret it, and it is not a good idea to be
> an accomplice in this sequence of events :-)
> 
> That being said, you can often suggest something that will help
> the student help themselves, and then everyone wins.
> 
> Robert De
> 
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.

Re: Kindness

[Robert Dewar]

In article <37D01A39.F05FF3F4@res.raytheon.com>,
  Andy Askey <askeya@res.raytheon.com> wrote:
> I haven't followed all the posts in this thread, but I just
can't help
> but put in my opinion here.
>
> Suppose the poster was a student attempting to get the answer
to some
> assigned question.  So what?  What is the difference if a
student reads
> the answer in a book, a man page, or from a newsgroup?  The
goal of the
> student (and the teacher, I hope) is that the student learns
from the
> homework.  One thing I find lacking in the education system of
today is
> that it does not prepare a graduate for the working world.
Once a
> student becomes a member of some Software Engineering
department, he/she
> will loose points for wasting time figuring out something that
is
> available by questioning an experience coworker.  Part of the
> educational process should be to teach how to complete a task
in the
> most efficient manner.  No one ever got a promoting
rediscovering
> something that is common knowledge through the industry.  But
plenty
> succeed by applying the knowledge of others to develop new
ideas.


Andy, reread the thread, I think you will find that people
basically agree with you. It is fine if you have a problem
to ask for help, it is not fine to ask someone else to do
your work for you, and then claim it as your own.

In fact when I teach CS courses, I explain at the start
that it is just fine to borrow code from anywhere, under
any circumstances *PROVIDING THAT* proper credit is given,
and I note that if the top of your assignment says "this
was written entirely by so-and-so who helped me out", that
this is not cheating, but you won't get much credit.

The one and ONLY offence is plagiarism, which is copying
without attribution. This is not acceptable even when you
have a "real" job. If a coworker writes a chunk of code
for you, then that coworker should get proper credit.

In fact the best thing to do when a student asks for help,
especially if the student makes it clear that he understands
that this is what is reasonable to ask for, is to point the
student in the right direction to learn.

Remember that when a professor gives out an assignment in a
CS course, the assignment is NOT to turn in a program that
does XYZ, it is to *learn* how to write a program that does
XYZ, and I think we all understand that doing things yourself
is an essential part of learning.

Would you hire someone who had never written a program, but
had instead got someone on CLA to write all their programs
for them? I doubt it, because while you may be able to persuade
someone to write a simple program for you, you don't see people
posting here the specs for a complex project and expecting
people to do it for them.

As for the net being different from books, it is not. If what
you do is to point people to appropriate net resources, that's
just fine, and we often try to do that. But if you do someone's
work for them, that's not at all equivalent to a book!

I think competent students understand the difference without
any difficulty.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[Andy Askey]

Robert,

Thanx for your response and I am glad to hear that proper SW reuse is
being taught today.  (This was taboo when I was in school 15 years
ago.)  One idea to stop "cheating" is for the professors to come up with
a unique problem for each class.  This may cause more work for the
instructor, but I think the final project may be more useful to the
student in the long run.

Andy Askey

Robert Dewar wrote:
> 
> Andy, reread the thread, I think you will find that people
> basically agree with you. It is fine if you have a problem
> to ask for help, it is not fine to ask someone else to do
> your work for you, and then claim it as your own.
> 
> In fact when I teach CS courses, I explain at the start
> that it is just fine to borrow code from anywhere, under
> any circumstances *PROVIDING THAT* proper credit is given,
> and I note that if the top of your assignment says "this
> was written entirely by so-and-so who helped me out", that
> this is not cheating, but you won't get much credit.
> 
> The one and ONLY offence is plagiarism, which is copying
> without attribution. This is not acceptable even when you
> have a "real" job. If a coworker writes a chunk of code
> for you, then that coworker should get proper credit.
> 
> In fact the best thing to do when a student asks for help,
> especially if the student makes it clear that he understands
> that this is what is reasonable to ask for, is to point the
> student in the right direction to learn.
> 
> Remember that when a professor gives out an assignment in a
> CS course, the assignment is NOT to turn in a program that
> does XYZ, it is to *learn* how to write a program that does
> XYZ, and I think we all understand that doing things yourself
> is an essential part of learning.
> 
> Would you hire someone who had never written a program, but
> had instead got someone on CLA to write all their programs
> for them? I doubt it, because while you may be able to persuade
> someone to write a simple program for you, you don't see people
> posting here the specs for a complex project and expecting
> people to do it for them.
> 
> As for the net being different from books, it is not. If what
> you do is to point people to appropriate net resources, that's
> just fine, and we often try to do that. But if you do someone's
> work for them, that's not at all equivalent to a book!
> 
> I think competent students understand the difference without
> any difficulty.
> 
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.

-- 
---------------------------------------------------
|                 Andy Askey                      |
|              Software Engineer                  |
|           Raytheon Systems Company              |
|   670 Discovery Drive, Huntsville, AL  35806    |
|   Phone: (256) 971-2367  Fax: (256) 971-2306    |
|        andrew_j_askey@res.raytheon.com          |
---------------------------------------------------

Re: Kindness

[Bill Findlay]

> Robert Dewar wrote:
...
> In fact when I teach CS courses, I explain at the start
> that it is just fine to borrow code from anywhere, under
> any circumstances *PROVIDING THAT* proper credit is given,
> and I note that if the top of your assignment says "this
> was written entirely by so-and-so who helped me out", that
> this is not cheating, but you won't get much credit.

This is our policy, spelled out to students in an 'ethical contract'
that they are obliged to read and sign at the start of the course.

> Remember that when a professor gives out an assignment in a
> CS course, the assignment is NOT to turn in a program that
> does XYZ, it is to *learn* how to write a program that does
> XYZ, and I think we all understand that doing things yourself
> is an essential part of learning.

Precisely!

-- 
Bill Findlay
Department of Computing Science
The University of Glasgow

Re: Kindness

[Jerry Petrey]

Mark Lundquist wrote:
> 
> I hate to see people get trashed on for asking an innocent question!
> 
> A while back, a guy posted to this group with a question about how to do
> something (or not do it) in Ada. One respondent, a respected expert in
> the Ada community, replied with a post that was pretty thoroughly
> contemptuous and condescending.
> 
> I don't get it!  The guy asking the question was willing to expose his
> ignorance, and he put the question clearly and courteously.  So why the
> insults?  I felt bad for the guy who asked the question and embarassed
> by this response.  Also, it was a great opportunity to point out some of
> the clear advantages of Ada, but it went to waste 'cause now that guy
> will probably go away thinking of Ada as the Language Of Buttheads.


Agreed!  It doesn't help the Ada cause much to react that way.  Except
for those who are just looking for someone to do their homework
assignment, I think we should do our best to give useful help.  Even
in those cases we can give polite suggestions to get them to do the
work and really learn something.

Jerry
-- 
=====================================================================
=  Jerry Petrey - Consultant Software Engineer  - Member Team Ada  
=                 Lockheed Martin                 Member Team Forth
=====================================================================

Re: Kindness

[Nick Roberts]

Hear! hear!

-------------------------------------
Nick Roberts
http://www.adapower.com/lab/adaos
-------------------------------------

Jerry Petrey <gpetrey@hercii.mar.lmco.com> wrote in message
news:37CE6B50.DE84D0EB@hercii.mar.lmco.com...
| Mark Lundquist wrote:
| >
| > I hate to see people get trashed on for asking an innocent question!
| >
| > A while back, a guy posted to this group with a question about how to do
| > something (or not do it) in Ada. One respondent, a respected expert in
| > the Ada community, replied with a post that was pretty thoroughly
| > contemptuous and condescending.
| >
| > I don't get it!  The guy asking the question was willing to expose his
| > ignorance, and he put the question clearly and courteously.  So why the
| > insults?  I felt bad for the guy who asked the question and embarassed
| > by this response.  Also, it was a great opportunity to point out some of
| > the clear advantages of Ada, but it went to waste 'cause now that guy
| > will probably go away thinking of Ada as the Language Of Buttheads.
|
|
| Agreed!  It doesn't help the Ada cause much to react that way.  Except
| for those who are just looking for someone to do their homework
| assignment, I think we should do our best to give useful help.  Even
| in those cases we can give polite suggestions to get them to do the
| work and really learn something.

Re: Kindness

[Matthew Heaney]

In article <37CC6844.AB898EEE@rational.com> , Mark Lundquist 
<mark@rational.com>  wrote:

> A while back, a guy posted to this group with a question about how to do
> something (or not do it) in Ada. One respondent, a respected expert in
> the Ada community, replied with a post that was pretty thoroughly
> contemptuous and condescending.

I don't think I'm the "respected expert" to whom you are referring, but I
think I responded to the question too.

If I'm thinking of the correct post to which you are referring, the question
was about how to fix up a very C-like solution to a problem of passing
arguments by reference.

> I don't get it!  The guy asking the question was willing to expose his
> ignorance, and he put the question clearly and courteously.  So why the
> insults?

Sometimes you have to drive home the point.  If you sound tenuous or
otherwise wishy-washy in your response, then the reader might infer from
your answer that the other way of solving the problem is OK too.

The problem is that the question itself was all wrong, and it was obvious
that the programmer hadn't really groked the Ada way of doing things.  So we
had to set this guy straight once and for all, that he's going to have to
learn a different way of writing computer programs.

> I felt bad for the guy who asked the question and embarassed
> by this response.

I wouldn't describe the response as an ad hominem attack.  Rather, it was a
forceful statement to the effect that the programmer's thinking is the real
problem, and that he's going to have to learn to think differently.

If someone's feelings get hurt by the tone of a response, well I'm sorry
about that, but sometimes life's a bitch.  Just try to hang in there.

> Also, it was a great opportunity to point out some of the clear advantages of
> Ada, but it went to waste 'cause now that guy will probably go away thinking
> of Ada as the Language Of Buttheads.

You learn the advantages of a language by programming in it, not by being
told how great it is.

--
Matt

It is impossible to feel great confidence in a negative theory which has
always rested its main support on the weak points of its opponent.

Joseph Needham, "A Mechanistic Criticism of Vitalism"

Re: Kindness

[James William Zuercher]

A very long time ago a very good friend of mine, and a very wise soul told me "If
anyone asks you for help, if it is within your means to provide what they ask for,
give it."  "You can't control what they do with what you give them."  "However they
thought they needed help and you have supplied it." "That is what truly matters."

Re: Kindness

[Robert Dewar]

In article <37D7FEC8.8EB3B2F4@msfc.nasa.gov>,
  James William Zuercher <James.Zuercher@msfc.nasa.gov> wrote:
> A very long time ago a very good friend of mine, and a very
wise soul told me "If
> anyone asks you for help, if it is within your means to
provide what they ask for,
> give it."  "You can't control what they do with what you give
them."  "However they
> thought they needed help and you have supplied it." "That is
what truly matters."


A dangerous philosophy indeed, for example, would you help
someone too drunk to do it themselves to put the ignition
key in the ignition lock of their car? It is easy to make
many other examples.

>
>


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re: Kindness

[Mark Lundquist]

Hmm, this thread has gone from "kindness", to "homework", and back to
"kindness" again, all on its own.  Will it ever make it back to Ada?  I doubt it...
:-)

James William Zuercher wrote:

> A very long time ago a very good friend of mine, and a very wise soul told me "If
> anyone asks you for help, if it is within your means to provide what they ask for,
> give it."  "You can't control what they do with what you give them."  "However they
> thought they needed help and you have supplied it." "That is what truly matters."

There's a kernel of truth there:  "You can't control what they do with what you give
them."  That may be true, but it doesn't excuse you from the responsibility to give
them the right thing.  The outcome of the scenario depends on both.  Your
responsibility ends where you have given the right thing -- not necessarily what they
asked for.

Crassly put, you are saying that your duty to the other person is to make them feel
good ("Ah, you gave me the help I asked for, thank you...").  But  doing that may be
detrimental to them, and it may be detrimental to you.

I highly recommend these two books for their clarity on this issue:

    - "Boundaries", by Henry Cloud and John Townsend.  Though it's written from a
Christian world view, I don't think their priniciples would be hard to swallow even
for an atheist (maybe some atheist can read the book and tell me if I'm right about
that... :-)

    - "Parenting With Love and Logic", by Jim Fay and Foster Kline.  The context is
child-raising, but the relational principles are pretty much universal.

Re: Kindness

[Robert Dewar]

In article <37D963E9.EFD1C218@rational.com>,
  Mark Lundquist <mark@rational.com> wrote:
> Hmm, this thread has gone from "kindness", to "homework", and
back to
> "kindness" again, all on its own.  Will it ever make it back
to Ada?  I doubt it...
> :-)

Probably not, but then the subject makes it clear enough that
it has nothing to do with Ada, so the possibility of it
veering back to Ada is small enough that people can kill it
without worrying :-) For a thread like this, it is actually
wrong to try to bend it back to Ada!


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.