Re: C getchar() functionality in Ada

[Thomas Locke <thomas@kenshi.dk>]

Georg Bauhaus wrote:
> We can write the same program in Ada, of course. :-)
> Only, the Ada version is likely written without
> resorting to the C's idiomatic
> "statement-used-as-expression-in-the-loop-conditional".
> 
> with Interfaces.C;
> 
> procedure C_1 is
> 
>    use Interfaces.C;
> 
>    function getchar return int;
>    function putchar(item: int) return int;
> 
>    pragma Import(C, getchar);
>    pragma Import(C, putchar);
> 
>    EOF: constant int := -1;             --  see <stdio.h>
>    c, not_checked: int;
> 
> begin
>    loop
>       c := getchar;
>       exit when C = EOF;
>       not_checked := putchar(c);
>    end loop;
> end C_1;


Thank you for this very nice example Georg!

I've experimented a bit on it, and the result is this:

-----
with Ada.Text_IO;  use Ada.Text_IO;

procedure Ito is

    function getchar return Integer;
    pragma Import (C, getchar);

    EOF   : constant Integer := -1;
    C     : Integer;

begin
    loop
       C := getchar;
       exit when C = EOF;
       Put (Character'Val (C));
    end loop;
end Ito;
-----

Basically I've just tried to get rid of the C putchar function, and 
instead use plain Put. Would the above be considered absolutely 
horrible, or?

/Thomas