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From: tmoran@acm.org
Newsgroups: comp.lang.ada
Subject: Re: How to do it in Ada ?
References: <9itna2$i5b$1@news.tpi.pl>
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Date: Mon, 16 Jul 2001 06:51:37 GMT
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> int main(int argc, char **argv)
> {
>     int *x;
>     int n;
>
>     n = (argc==1)?1:atoi(argv[1]);
>     x = malloc (n*sizeof(int));
>     for (x=0;x<n;x++)
>         x[i]=0;
>
>     /* ... */
> }

The most natural Ada way is:

with Ada.Command_Line;
procedure Main is
  N : Integer;
begin
  if Ada.Command_Line.Argument_Count = 0 then N := 1;
  else N := Integer'value(Ada.Command_Line.Argument(1));
  end if;
  declare
    X : array(1 .. N) of Integer := (others=>0);
  begin
    ....
  end;
end Main;

> Something like that ... how to do such dynamic array allocation in Ada ?
  If you mean heap allocation, not just dynamic stack allocation,
then:

with Ada.Command_Line;
procedure Main is
  N : Integer;
  type X_Array_Type is array(Integer range <>) of Integer;
  type Px_Type is access X_Array_Type;
  X : Px_Type;
begin
  if Ada.Command_Line.Argument_Count = 0 then N := 1;
  else N := Integer'value(Ada.Command_Line.Argument(1));
  end if;
  X := new X_Array_Type'((1 .. N => 0));
    ....
end Main;