From: "F" <phosphorus@libero.it>
Subject: Re: a little help
Date: Tue, 16 Oct 2001 14:23:58 +0200
Date: 2001-10-16T14:23:58+02:00 [thread overview]
Message-ID: <9qh8lt$1he7$1@newsreader1.mclink.it> (raw)
In-Reply-To: slrn9snplt.ja.gerhard.nospam@lilith.hqd-internal
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Thank you for your help but i've modified the procedure (now ind is an
in-side variable and the parameter j is in out) and there are still the same
problems.
The problem is the second recall of my procedure.
Please help me................. :-)
P.S.
I send you the entire new program
procedure prova is
type st is new string;
b:st(1..20);
ind:integer:=1;
procedure leggis (j: in out st; i: in out integer) is
c:character;
begin
while not end_of_line loop
get(c); j(ind):=c; i:=i+1;
end loop;
end leggis;
begin
new_line;
leggis(b,ind);
for i in 1..ind loop
put(b(i));
end loop;
ind:=1;
new_line;
--this is the beginning of my problems!!
leggis(b,ind);
for i in 1..15 loop
put(b(i));
end loop;
end prova;
Gerhard H�ring ha scritto nel messaggio ...
>On Tue, 16 Oct 2001 10:39:14 +0200, F <phosphorus@libero.it> wrote:
>>Hello world,
>> i'm trying to learn Ada but i've a lot of problems with the
>>operations with strings.
>>In particular i've a procedure for the input:
>>
>>type st is new string;
>>procedure leggis (j: in out st) is
>> c:character;
>>begin
>> while not end_of_line loop
>> get(c); b(ind):=c; ind:=ind+1;
>> end loop;
>>end leggis;
>>
>>
>>when i call the first time this procedure i obtain the input string but
the
>>second time nothing happens.....
>>I think that character return remains in the keyboard buffer, how can I
>>resolve this problem?????
>
>Looks like you're not telling us the whole story. Where do the b and ind
>variables come from? Looks like they *should* be put in the procedure
>but they're now declared and initialized outside in (global?) variables.
>This means you get so-called side-effects when running the procedure:
>the procedure isn't self-contained but changes state elsewhere. This
>usually leads to bugs sooner or later.
>
>Solution: put all variables into the proecedure and initialize them
>there, too. ind should be initialized to 0 if I see this correctly.
>
>If you want to improve the code even further, you can make the j
>parameter "out" instead of "in out", but even better would be to make
>the whole thing a function instead.
>
>Gerhard
>--
>mail: gerhard <at> bigfoot <dot> de registered Linux user #64239
>web: http://www.cs.fhm.edu/~ifw00065/ OpenPGP public key id 86AB43C0
>public key fingerprint: DEC1 1D02 5743 1159 CD20 A4B6 7B22 6575 86AB 43C0
>reduce(lambda x,y:x+y,map(lambda
x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))
next prev parent reply other threads:[~2001-10-16 12:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-10-16 8:39 a little help F
2001-10-16 9:50 ` Gerhard Häring
2001-10-16 12:23 ` F [this message]
2001-10-16 15:47 ` Gerhard Häring
2001-10-16 15:46 ` Martin Dowie
2001-10-16 15:29 ` Ted Dennison
2001-10-17 7:11 ` F
2001-10-17 14:26 ` Ted Dennison
2001-10-17 10:00 ` Preben Randhol
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