Re: Zoo question

[husseinp@logica.co.uk (Paul Hussein)]

Ken Garlington <garlingtonke@lmtas.lmco.com> wrote:

>Here's a little brain teaser we received recently. Assuming no typos or 
>other obvious syntax errors, will the Fill procedure work in Ada 83?

>package Zoo is

>  type Animal_ID is range 1 .. 5; -- yes, an enumeration type might be
> 	                                -- better, but it spoils the example!

>  subtype Cage_ID is Positive range 1 .. 12;

>  type Cage_Row is array (Cage_ID) of Animal_ID;

>  -- Fill fills a row of cages with various animals, in sequential order
>  -- with alternating animals
>  procedure Fill ( Cages : in out Cage_Row );

>end Zoo;

>package body Zoo is

>  procedure Fill ( Cages : in out Cage_Row ) is
>    Next_Animal : Animal_ID := Animal_ID'First;
>  begin -- Fill
>    for Cage in Cages'Range loop

>      Cages(Cage) := Next_Animal;

>      Get_Next_Animal: begin -- look carefully at this code!
>        Next_Animal := Animal_ID'Succ(Next_Animal);
>      exception
>        when others => Next_Animal := Animal_ID'First;
>      end Get_Next_Animal;

>    end loop;
>  end Fill;

>end Zoo;
 I think it will 'work' also, but is not good example of ADA using
exceptions in that way.


I know youre going to come up with some more subtle problem.