Re: while-question
| From: | Jochem Maas | Date: | Mon, 17 Nov 2008 18:07:53 +0000 |
| Subject: | Re: while-question | ||
| References: | 1 2 3 4 5 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-283381@lists.php.net to get a copy of this message | ||
Robert Cummings schreef:
> On Mon, 2008-11-17 at 14:54 +0000, Stut wrote:
>> On 17 Nov 2008, at 14:31, Nathan Rixham wrote:
>>> if you really want a challenge try this one..
>>>
>>> task: add the numbers 5 and 17 together, using php, without using
>>> the + operator. fill it in:
>>>
>>> function add($a , $b) {
>>> //code here but no + - / * operators
>>> return $answer;
>>> }
>>>
>>> echo add(5, 17);
>> Elemental my dear Mr Rixham...
>
> What level is that elemental?
well it's all bitwise operating ... can't get much more
elemental that a bit in CS. but I think he meant to
say elementary (assuming the Sherlocks Holmes catchphrase)
>
>> function add($a , $b)
>> {
>> $answer = $a ^ $b;
>> while (0 != ($a & $b))
>> {
>> $b = ($a & $b) << 1;
>> $answer = $answer ^ $b;
>> }
>> return $answer;
>> }
nice, I think :P
> He only said you couldn't use the + operator... nothing was said about
> using the - operator.
<quote>
//code here but no + - / * operators
</quote>
>
> $total = -(-5 - 17);
>
> Cheers,
> Rob.