Re: inconsistent float behaviour
Re: inconsistent float behaviour
- Subject: Re: inconsistent float behaviour
- From: "Clark Cox" <email@hidden>
- Date: Fri, 10 Oct 2008 19:23:40 -0700
On Fri, Oct 10, 2008 at 6:33 PM, Steven Hamilton <email@hidden> wrote:
> Thanks guys,
> I'm still unsure why I'm getting 4 decimal places as I know for fact that
> the data is 2 decimal places.
That is because floating point numbers don't have "decimal places";
forget all about decimal places. Please read this:
<http://docs.sun.com/source/806-3568/ncg_goldberg.html>, it is, as the
title says: what every computer scientist should know about
floating-point arithmetic.
> However, it seems my approach is wrong. I'll
> convert to int's and NSDecimalNumbers instead and remove all floats.
>
> On 11/10/2008, at 4:14 AM, Uli Kusterer wrote:
>
>> On 10.10.2008, at 13:04, Steven Hamilton wrote:
>>>
>>> NSLog(@"current balance is: %@",balance);
>>>
>>> and get
>>>
>>> current balance is: 18976.69
>>>
>>> in the console. So far so good.
>>>
>>> (...) The float calculation is exactly 2 decimal places, I know that for
>>> a fact and NSLog proves it.
>>
>> You may want to be aware that NSLog gives no guarantees as to the output
>> of its formats if you use %@. All it does is call the -description method of
>> the requisite object. -description is only intended for debugging, and as
>> such what it returns for a particular object may change from release to
>> release, or even from instance to instance (e.g. when you log an NSArray,
>> you occasionally get more detailed output than when logging a
>> toll-free-bridged CFArrayRef).
>>
>> Cheers,
>> -- Uli Kusterer
>> "The Witnesses of TeachText are everywhere..."
>> http://www.zathras.de
>>
>>
>>
>>
>>
>
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--
Clark S. Cox III
email@hidden
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