From: username
Subject: sets operations
Date: 
Message-ID: <3B97A9AA.812135EA@cisco.com>
Hi Dear all,

I'd like to use Lisp language to implemet following operations on Set.

-  Set Union
-  Set Difference
-  Set Interaction

Detailed requirement like this:

Set Union, Set Difference, And Set Intersection.
Implement these three operations on
sets. You should be able to handle two sets as input at a minimum,
ideally any number of sets. If you need to look up these set
operations in a discrete math book, then do that. The input
representation and output representation is up to you. However, the
results should not contain duplicates (e.g., if set X = (1 2 3) and
set Y = (2 3 4) then X + Y (X UNION Y) = (1 2 3 4) NOT (1 2 2 3 3 4)
and so on).

Example: (and this is ONLY NOTIONAL - An IDEA not a specification)

INPUT FILE
----------
SET A = {a b c d e}
SET B = {x y z a}
* <--- meaning INTERSECTION
---------
Your program should perform set intersection and print out 'a'.

I heard it should be easy by using Lisp.

Any suggestions on that?

Thanks,
:-)

From: Barry Margolin
Subject: Re: sets operations
Date: 
Message-ID: <4XNl7.19$aL1.190@burlma1-snr2>
In article <·················@cisco.com>, username  <········@cisco.com> wrote:
>I heard it should be easy by using Lisp.

Common Lisp has built-in functions REMOVE-DUPLICATES, UNION, INTERSECTION,
and SET-DIFFERENCE.  I'm guessing your teacher doesn't want you to use
these, though.

>Any suggestions on that?

Do your own homework.

-- 
Barry Margolin, ······@genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.
From: Erik Naggum
Subject: Re: sets operations
Date: 
Message-ID: <3208787616926057@naggum.net>
* username <········@cisco.com>
> Set Union, Set Difference, And Set Intersection.

  Do union, intersection and set-difference fulflll your needs?
  These are standard functions in Common Lisp.

///