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

[H. S. Teoh]

On Thu, Jun 27, 2013 at 12:43:04AM +0200, David wrote:
> Am 26.06.2013 22:51, schrieb Gary Willoughby:
> > 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?
> > 
> > http://stackoverflow.com/questions/731832/interview-question-ffn-n
> 
> I solved it ;)
> 
> http://dpaste.dzfl.pl/5cd56e9d
[...]

Well, technically it's invalid because it says "design *a* function f".

But maybe it can be salvaged:

	auto f(T)(T n) {
		static if (is(T==int))
			return cast(double)n;
		else if (is(T==double))
			return -cast(int)n;
		else static assert(0);
	}

Well, it's still cheating, though. :-P I think the 4-cycle algorithm is
probably still the best one I've seen.

A more interesting interview question, IMO, would be to design a
function of the form:

	bool f(void delegate(int) dg, int n);

which returns true if dg(n) returns, and false otherwise.

:-P


T

-- 
Three out of two people have difficulties with fractions. -- Dirk Eddelbuettel