Re: Some problems with string type

[Valdes <valdesl@wanadoo.fr>]

Philip Anderson a �crit :

> Valdes wrote:
> >
> > I have my program writen in Ada that raise some exceptions:
> >
> > raised CONSTRAINT_ERROR : gestindex.adb:5
> >
> > ... And at line 5...
> >
> >  function createindex (S:string) return index is
> >       I:Index;
> >    begin
> >       i.nameindex:=s; -- Ligne cinq
>
> Note that Constraint Error will be raised if s is not _exactly_ 20
> characters long.

I have undertood this one. It works fine now.

>
> >       i.firstletter:=null;
> >       return i;
> >    end createindex;
> >
> > ... The index record is defined as follow...
> >
> >   type index is record
> >       nameindex:String(1..20);
> >       firstletter:ptrletter;
> >    end record;
> >
> > ... The mistake seems to be trivial but I don't see it.
> >
> > I have seen the same for this also:
> >
> >     Ptrtemp.Letter:=Charat(M,Ni);
> >
> > there is the same error but Charat return a character and letter is also
> > one. (ptrtemp is also type ptrlettre)
>
> Is M a String and Ni an index into it?

M is not exactly a string. It is a pointer to a string. I had to make this one
for the first error.

>  If so Ni must be within the
> range M'first .. M'last, and M'first may be greater than 1 (and won't be
> 0).

Perhaps I have better to show the function:


--------------------------------------
  function addwordtoindex(I :Index;M:word) return Index is
      ptrtemp:ptrword:=I.firstletter;
      aux:firstletter;
      J:Index;
      long,Ni:Natural;
      B:Boolean;
   begin
      long:=Lengthword(M);Ni:=1;

      if (ptrtemp /= Null) then
         while(ptrtemp /=null) loop
            Aux:=ptrtemp;
            if (ptrtemp.letter /=Charat(M,ni+1)) then
               ptrtemp:=ptrtemp.right;
               B:=false;
            else
               ptrtemp:=ptrtemp.bottom;
               ni:=ni+1;
               B:=True;
            end if;
         end loop;
         ptrtemp:=Aux;
         if (B) then
            ptrtemp.bottom:=new Cellword;
            ptrtemp:=ptrtemp.bottom;
            Ptrtemp.letter:=Charat(M,Ni+1); --possible exception
         else
            ptrtemp.Droite:=new Celword;
            ptrtemp:=ptrtemp.right;
            Ptrtemp.Letter:=Charat(M,Ni+1);  --possible exception

         end if;
      else
          Ptrtemp:=new Cellword;
          Ptrtemp:=I.firstletter;
          Ptrtemp.Letter:=Charat(M,Ni);  --possible exception


      end if;
      Ni:=ni+1;

      while(ni<Long)loop
         ptrtemp.bottom:=new Cellword;
         ptrtemp:=ptrtemp.bottom;
         ni:=Ni+1;
      end loop;
      ptrtemp.end:=True;
      J.Nomindex:=I.nameindex;
      J.Premlettre:=I.firstletter;
      return J;
   end addwordtoindex;
------------------------
I use this function to put some words whose letters will be put into an index
- a tree -
They are an other function whose functionnality is to create a new index.
This one (that I show there) works bad.

The tree(with the words phone and phoque) :

p
|
h
|
o
|
n-q
| |
e u
  |
  e



          |
one node: r- right
          |
          bottom

And the signature:

Package Gestindex is

   type index is private;
   type cellword is private;
   type ptrword is access cellword;
   function addwordtoindex (I:Index;M:word) return index;

private
   type cellword is record
      word: character;
      bottom: ptrlettre;
      right: ptrlettre;
      end: Boolean;
   end record;

   type index is record
      nameindex:Mot;
      firstletter:ptrword;
   end record;
end Gestindex;

>
> > All my greetings if you have some ideas. And forgive me for my bad
> > english.
>
> Pas de probleme.

Thank you. All my greetings.


> > --
> > Le Vif Z�phyr Jubile Sur Les Kumquats Du Clown Gracieux.
> The quick brown fox jumps over the lazy dog.

Where did you read this sentence ? On some Macintosh ? ;-)