round() for float in C++

Question

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

Answer 1

Since C++ 11 simply:

#include 
std::round(1.1)

or to get int

static_cast(std::round(1.1))