Re: a little help

[gerhard.nospam@bigfoot.de (Gerhard Häring)]

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
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reduce(lambda x,y:x+y,map(lambda x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))