H. S. Teoh:
> > bool isKaprekar(in long n) pure nothrow
> > in {
> > assert(n > 0, "isKaprekar(n): n must be > 0");
> > assert(n <= uint.max, "isKaprekar(n): n must be <= uint.max");
> > } body {
> [...]
>
> Shouldn't you just use "in ulong n" as parameter instead of long with a
> contract?
In this case the answer is probably positive.
But in general it's better to accept a signed number and then refuse the
negative values in the pre-condition, otherwise if you give by mistake a
negative number to the function it's not caught.
Such work-arounds are less needed in saner languages, where the ranges of
integral values are verified, at compile time where possible, and at run-time
otherwise. Unwanted wrap-arounds and undetected overflows in integral values
are so '70 :-)
Bye,
bearophile
