From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,341730abd589d6e9
X-Google-Attributes: gid103376,public
From: Jeff Carter <jrcarter@acm.org>
Subject: Re: string operations
Date: 2000/11/18
Message-ID: <3A16C006.B79A599@acm.org>#1/1
X-Deja-AN: 695148892
Content-Transfer-Encoding: 7bit
References: <3A16A4D5.CE941970@t-online.de>
X-Accept-Language: en
Content-Type: text/plain; charset=us-ascii
X-Complaints-To: abuse@earthlink.net
X-Trace: newsread1.prod.itd.earthlink.net 974569601 165.121.234.130 (Sat,
 18 Nov 2000 09:46:41 PST)
Organization: EarthLink Inc. -- http://www.EarthLink.net
MIME-Version: 1.0
NNTP-Posting-Date: Sat, 18 Nov 2000 09:46:41 PST
Newsgroups: comp.lang.ada
Date: 2000-11-18T00:00:00+00:00
List-Id: <comp.lang.ada>

Margit Gut wrote:
> I try to read a string from the keyboard and then I want to write a
> recursiv function to turn the characters  from the end to the beginning.

The requirement that this be a recursive function sounds like a homework
problem.

> 
> I fetch the string with Get_Line. I declared the string with
> Sstring : string(1..255);
> So whatever I try, the string'Length is always 255.

Given the declaration

S : String (1 .. 255);

S'Length is always 255. This is the definition of the 'Length attribute
on an array object.

Look carefully at the description of Get_Line in the ARM (A.10.7),
especially the meaning of the Last parameter, and then read about slices
(ARM 4.1.2). You can find the ARM on line at

http://www.adapower.com/rm95/index.html

If the string read by Get_Line is shorter than its Item parameter, it is
stored in Item (Item'First .. Last). Thus, after executing

Get_Line (Item => S, Last => Last);

the string of interest is in the slice

S (S'First .. Last)

>  My next poblem is, how to do a correct Function, that calls itselve.

A function calls itself exactly the same way that any other statement
calls the function:

function F (N : Positive) return Positive is
begin -- F
   if N <= 1 then
      return N;
   else
      return N * F (N - 1);
   end if;
end F;

-- 
Jeff Carter
"You tiny-brained wipers of other people's bottoms!"
Monty Python & the Holy Grail