Re: what's wrong with random

[see@messagebody.com (Jan)]

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On Sun, 22 Dec 2002 18:38:33 GMT, Robert A Duff
<bobduff@shell01.TheWorld.com> wrote:

>I think you want the generator to be global to Generate_FileName.
>Otherwise, it will be reinitialized each time Generate_FileName
>is called.
>
>- Bob

What do you mean? Can you give an example?
Here is a working version:
--------
with Ada.Text_IO, Ada.Numerics.Discrete_Random;
use  Ada.Text_IO;

procedure Random_Test is 

   valid_chars : String :=
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
                     & "0123456789!�$%&()=@+-;_#";  

   subtype Int_Slice is Integer range valid_chars'range;
   package My_Random is new Ada.Numerics.Discrete_Random (Int_Slice);

   function Generate_FileName (Length : Positive) return String is 
      G      : My_Random.Generator;  
      I      : Int_Slice;  
      Result : String (1 .. Length);  
   begin
      My_Random.Reset(G);

      for X in 1..Length
            loop
         I := My_Random.Random(G);
         Result(X) := valid_chars(I);
      end loop;
      return Result;
   end Generate_FileName;

begin

   for X in 1..10
   loop
      Put_Line(Generate_Filename(8));
   end loop;

end Random_Test;

---------------

When I put

   subtype Int_Slice is Integer range valid_chars'range;
   package My_Random is new Ada.Numerics.Discrete_Random (Int_Slice);

into the function, nothing changes.

Thanks.