Re: Ada function sqrt(x)

["W. Wesley Groleau (Wes)" <wwgrol@PSESERV3.FW.HAC.COM>]

Matthew Heaney <mheaney@NI.NET> suggests:

> If you really want a function to do integer square roots, here it is (my
> Ada 95 syntax may not be quite right):

Well, perhaps more than syntax.  Suppose I call an instance with a parameter
of 25......

                                                         Iteration

> generic                                                   1   2   3  ...
>   type T is range <>;
> function Generic_Square_Root (N : T) return T'Base;
>
> function Generic_Square_Root (N: T) return T'Base is
>   The_Square_Root : T'Base := N/2;                       12
> begin
>   loop
>     declare
>       The_New_Value : constant T'Base :=
>            (The_Square_Root + N / The_Square_Root) / 2;   1   1   1   ...
>     begin
>       exit when The_New_Value = The_Square_Root;         no  no  no   ...
>     end;
>   end loop;
>
>   return The_Square_Root;
> end Generic_Square_Root;

At the risk of being flamed for inefficency:

function Integer_Square_Root ( N : T ) is

  Temp : constant T'Base :=
         T'Base ( Ada.Numerics.Elementary_Functions.Sqrt ( Float (N) ) );

begin

  if Temp * Temp /= N then

     raise Some_Package.Input_Is_Not_An_Integer;

  else

    return Temp;

  end if;

end Integer_Square_Root;

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