Re: Integers and Mathematical Correctness

[Tucker Taft <stt@avercom.net>]

"chris.danx" wrote:
> ...
> The problem is this...
> 
>    type c_integer is new integer;
> 
>    function "/" (a, b : c_integer) return c_integer is
>    begin
>       return standard."/" (a, b); -- simple test of override
>    end "/";
> 
> The line > standard."/" (a, b) doesn't work!  I check the RM and the "/" for
> integers is defined in standard, but it's not accepting it...

Change the line to:

     return standard."/"(integer(a), integer(b));

The "/" in standard operates on integer, not c_integer.

In fact, you don't need the "standard." part because
overload resolution will find the operator, so long
as you do the conversion.  Hence, the following will work:

    return integer(a) / integer(b);

Or if you want to ensure that the remainder is positive:

    if a < 0 then
        return - ((-integer(a))/integer(b));
    else
        return integer(a)/integer(b);
    end if;

[Note that this might overflow if integer(a) = integer'first.]


> ...
> Thanks,
> Chris

-- 
-Tucker Taft   stt@avercom.net   http://www.avercom.net
Chief Technology Officer, AverCom Corporation (A Titan Company) 
Bedford, MA  USA (AverCom was formerly the Commercial Division of AverStar:
http://www.averstar.com/~stt)