How would you solve this 'interview' question in D?

[Steven Schveighoffer]

On Thu, 27 Jun 2013 04:09:39 -0400, monarch_dodra <monarchdodra at gmail.com>  
wrote:

> On Wednesday, 26 June 2013 at 21:00:42 UTC, Adam D. Ruppe wrote:
>> On Wednesday, 26 June 2013 at 20:51:35 UTC, Gary Willoughby wrote:
>>> Just for a bit of fun, I saw this question posted on reddit the other  
>>> day and wondered how *you* would solve this in D?
>>
>> Since they didn't say *pure* function, I'd cheat:
>>
>> int f(int n) {
>>   static bool isOddCall;
>>   isOddCall = !isOddCall;
>>   if(!isOddCall)
>>       return -n;
>>   return n;
>> }
>>
>> :P
>
> Well if you solved it *that* way, *I* wouldn't hire you :p

TBH, if working there required writing such functions, I wouldn't want to  
:)

-Steve