Re: Newbie's question [SOLVED]

[Christos Chryssochoidis <C.Chryssochoidis@gmail.com>]

I changed version of GNAT and now the code runs ok.



Christos Chryssochoidis wrote:
> 
> Hello,
> 
> I 'm experimenting with Ada, and I'm having trouble getting some toy 
> code running. The code is the following: (hope it isn't too complicated)
> 
> 
> -- This is a program to test passing subprograms as arguments to other 
> subprograms.
> -- It consists of a main program, "Test_Filter", and two nested 
> subprograms: "Filter" and "Greater_Equal_3". The "Filter" subprogram 
> takes as arguments an array of Integers and a function (predicate), and 
> returns an array of the same type, having only those elements of the 
> input array that satisfy the given predicate. For some reason that I 
> can't figure out, I'm getting a "segmentation fault" when I run the 
> executable. (It compiles fine.)
> 
> 
> with Ada.Containers.Doubly_Linked_Lists;
> with Ada.Text_IO;
> 
> procedure Test_Filter is
> 
>    subtype Index is Natural;
>    type Int_Array is array(Index range<>) of Integer;
> 
> 
>    function Filter(Elements : Int_Array; Predicate : not null 
> access                     function(Element : Integer) return 
> Boolean)                                 return Int_Array  is
>       package Int_Lists is new                                      
> Ada.Containers.Doubly_Linked_Lists(Element_Type => Integer);
>       Tmp_List : Int_Lists.List;
>       Result : access Int_Array;
>    begin
>       for I in Elements'Range loop
>          if Predicate(Elements(I)) then
>             Tmp_List.Append(Elements(I));
>          end if;
>       end loop;
> 
>       Result := new Int_Array(1..Index(Tmp_List.Length));
>   Copy_List:
>       declare
>          Tmp_List_Cursor : Int_Lists.Cursor := Tmp_List.First;
>          I : Integer := 1;
>       begin
>          while Int_Lists.Has_Element(Tmp_List_Cursor) loop
>             Result(I) := Int_Lists.Element(Tmp_List_Cursor);
>             Tmp_List_Cursor := Int_Lists.Next(Tmp_List_Cursor);
>             I := I + 1;
>          end loop;
>       end Copy_List;
> 
>       return Result.all;
> 
>    end Filter;
> 
>    function Greater_Equal_3(Element :Integer) return Boolean is
>    begin
>       if Element >= 3 then
>          return True;
>       else
>          return False;
>       end if;
>    end Greater_Equal_3;
> 
> 
>    Int_Array1 : Int_Array := Int_Array'(1,2,3,4,5);
>    Int_Array2 : Int_Array(1..3);
> 
> begin
>    Int_Array2 := Filter(Int_Array1, Greater_Equal_3'Access);
>    for I in Int_Array1'Range loop
>       Ada.Text_IO.Put_Line(Int_Array1(I)'Img);
>    end loop;
> 
>    Ada.Text_IO.Put_Line("");
> 
>    for I in Int_Array2'Range loop
>       Ada.Text_IO.Put_Line(Int_Array2(I)'Img);
>    end loop;
> 
> end Test_Filter;
> 
> 
> Thanks very much for any help.