Re: oo problem help please

[Martin Krischik <krischik@users.sourceforge.net>]

shoko wrote:

> what is wrong with the following code:

Wrong choices

> ----car.ads----
> package car is
>   --car class --
>   type car is tagged private;
>   type car_ptr is access all car'class;
>   
>   --car methods --
>   procedure set_name(name:String;this:in out car);
>   function  get_name(this:car) return string;
>   
>  private
>      type car is tagged
>      record
>          name:String(1..256);
>      end record;
>   

I don't belive that every name should be 256 characters long.

> begin
>ￜￜￜￜￜcars(1)ￜ:=ￜcar_ptr(initbus("mercedes"));
ￜￜ
Yes "mercedes" is not 256 Characters. You should take a look at

http://www.adaic.org/standards/95lrm/html/RM-A-4-4.html
http://www.adaic.org/standards/95lrm/html/RM-A-4-5.html

Fact is that you got the wrong type of string. If there is a max lenght
(like you want to store your vechicles in a database) then use
Ada.Strings.Bounded if not use Ada.Strings.Unbounded.

Or if the name is constant use a discriminant:

type car (
    Name_Lenght : Positive)
is tagged record
    name : String(1 .. Name_Lenght);
end record;

With Regards

Martin

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