shortest funtion c++ of rounding a float number

Question

Which is the shortest form of this function(without changing the name of this)?

int NearestInteger(float N) 
{
    return round(N);
}

Answer 1

You can use std::round function if you have C++11.

Otherwise, you may need to use one of them depends on your requirement std::floor or std::ceil

Answer 2

If you don't have C++11, you can do this:

int NearestInteger(float N) {
    return int(floor(N + 0.5f));
}

However, it may work incorrectly for large floats. First of all, if your number does not fit int , any trash can be returned. Second, it may return wrong results for numbers larger than 2^24, because not each integer is exactly representable in single precision float number .