I need a simple floating point rounding function, thus:
double round(double);
round(0.1) = 0
round(-0.1) = 0
round(-0.9) = -1
I can find ceil()
and floor()
in the math.h - but not round()
.
Is it present in the standard C++ library under another name, or is it missing??
There's no round() in the C++98 standard library. You can write one yourself though. The following is an implementation of round-half-up:
double round(double d)
{
return floor(d + 0.5);
}
The probable reason there is no round function in the C++98 standard library is that it can in fact be implemented in different ways. The above is one common way but there are others such as round-to-even, which is less biased and generally better if you're going to do a lot of rounding; it's a bit more complex to implement though.