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From: mheaney@ni.net (Matthew Heaney)
Subject: Re: "<" operator
Date: 1997/10/07
Message-ID: <mheaney-ya023680000710971821260001@news.ni.net>#1/1
X-Deja-AN: 279194354
References: <343A7434.36AD@newtimes.com>
Organization: Estormza Software
Newsgroups: comp.lang.ada
Date: 1997-10-07T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <343A7434.36AD@newtimes.com>, dperez <dperez@newtimes.com> wrote:

>how can I write a recursive Ada Function "<" that does the less-than
>comparison on linked lists of characters to do the obvious thing?

function "<" 
  (L, R : Character_List) return Boolean is
begin
   if L = null then
      if R = null then
         return True;
      else
         raise <lists are not same length error>;
      end if;

   elsif R = null then
      raise <lists are not same length error>;

   else
      return L.Item < R.Item and L.Next < R.Next;

   end if;
end;


Won't that do it?

The type is

   type Character_List_Node;
   type Character_List is access Character_List_Node;

   type Character_List_Node is
      record
         Item : Character;
         Next : Character_List;
      end record;

   function "<" (L, R : Character_List) return Boolean;

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Matthew Heaney
Software Development Consultant
<mailto:matthew_heaney@acm.org>
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