Fast ceiling of an integer division in C / C++
Given integer values x
and y
, C and C++ both return as the quotient q = x/y
the floor of the floating point equivalent. I'm interested in a method of returning the ceiling instead. For example, ceil(10/5)=2
and ceil(11/5)=3
.
The obvious approach involves something like:
q = x / y;
if (q * y < x) ++q;
This requires an extra comparison and multiplication; and other methods I've seen (used in fact) involve casting as a float
or double
. Is there a more direct method that avoids the additional multiplication (or a second division) and branch, and that also avoids casting as a floating point number?