Re: how to round integers (Figured it out!)

[Jeffrey Carter <spam@spam.com>]

Robert I. Eachus wrote:
> Jeffrey Carter wrote:
> 
>> Robert I. Eachus wrote:
>>
>>>   function Round is new Rounding(Integer);
>>
>> What happens in the case of negative arguments?
> 
> Oops!  New version for the new requirement. ;-) And if you think it is 
> messy, it is, that is the nature of division, as Intel and others have 
> found out. (It is actually the corner cases that are tricky--and you 
> really have to test all of them.)

Not really a new requirment. Your generic specification clearly allows 
instantiation with subtypes that include negative values (such as your 
instantiation with Integer), so clearly the function is intended to 
handle negative arguments :)

Yes, it is messy. So I would have made it a generic package, with the 
following declarations:

subtype Natural_Int  is Int range 0 .. Int'Last;
subtype Positive_Int is Int range 1 .. Int'Last;

function Rounding (Dividend : Natural_Int; Divisor : Positive_Int)
return Int;

Then your original algorithm would be fine.

-- 
Jeff Carter
"You tiny-brained wipers of other people's bottoms!"
Monty Python & the Holy Grail