The semantics of div() is different than the semantics of % and /, which is important in some cases.
That is why the following code is in the implementation shown in psYchotic's answer:
if (numer >= 0 && result.rem < 0)
{
++result.quot;
result.rem -= denom;
}
% may return a negative answer, whereas div() always returns a non-negative remainder.
Check the WikiPedia entry, particularly "div always rounds towards 0, unlike ordinary integer division in C, where rounding for negative numbers is implementation-dependent."
