|
|
Posted by bill on 02/01/08 19:23
Jerry Stuckle wrote:
> The Natural Philosopher wrote:
>> Jerry Stuckle wrote:
>>> The Natural Philosopher wrote:
>>>> Rik Wasmus wrote:
>>>>> On Fri, 01 Feb 2008 16:59:18 +0100, The Natural Philosopher <a@b.c>
>>>>> wrote:
>>>>>> The question says it all.
>>>>>>
>>>>>> I have an input box, which I fill in with a price.
>>>>>> IOt gets passed to the main form as a variable, then shoved into
>>>>>> an SQL field vue a print '%d' statement where the argument is
>>>>>> $price*100.
>>>>>
>>>>> Could you give us the exact code & input values? And what database
>>>>> (&version) are you using?
>>>>>
>>>>>> For some reaosn, this particular value goes to 6998.
>>>>>>
>>>>>> If I update hee database manually to 6999, it displays as 69.99.
>>>>>>
>>>>>> If I enter 69.999 it updates as 6999..not 69999
>>>>>
>>>>> Seems to have something to do with float/double precision. However,
>>>>> the precision isn't that big, and I cannot reproduce it in PHP 5.2
>>>>> here..
>>>>>
>>>>> PHP5.2.4:
>>>>> <?php echo 69.99*100 ?> => output 6999
>>>>> MySQL5.0.45-community-nt:
>>>>> SELECT CAST(69.99*100 AS UNSIGNED); => 6999
>>>>
>>>> Rik. Its worse than that NOTHING to do with databases.
>>>>
>>>> Here is a code fragment.
>>>>
>>>> echo $sale_price."<br>\r\n"; // gives 69.99
>>>> printf ("%d<br>\r\n",($sale_price*100)); //gives 6998
>>>> $xxx=$sale_price*100;
>>>> echo $xxx."<br>\r\n"; // gives 6999
>>>> printf ("%d<br>\r\n",$xxx); //gives 6998
>>>>
>>>>
>>>> Now $sale_price comes from a text type input via a _POST_ variable,
>>>> so I guess its 'text' as its raw form PHP invisible casting drives
>>>> me nuts, so you can tell ME what $xxx is...
>>>>
>>>
>>> According to the PHP manual:
>>>
>>> %d - the argument is treated as an integer, and presented as a
>>> (signed) decimal number.
>>>
>>> Which means it is truncating instead of rounding.
>>>
>>> 69.99 is not exact. It's approximately 69.98999999999999488409.
>>>
>>> So 69.99*100 comes out to be 6998.999999999999488409 and truncated
>>> you get 6998.
>>>
>> Right. So every other php funtion treats 6999 as 6999,. except
>> printf's %d.
>>
>> If you use %s, it works..
>>
>> Invisible casting has to be the worst thing ever. That's WHY I did it
>> all in cents (or pence)to avoid these pissing float issues.
>>
>> Is there a function that takes 69.99*100 and makes it a properly
>> rounded integer?
>>
>>
>>
>>
>>
>>
>
> round().
>
A bit verbose, don't you think, Jerry ? <g>
Navigation:
[Reply to this message]
|