round() for float in C++
c++, floating-point, rounding
Solution
It's available since C++11 in cmath (according to http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf)
#include <cmath>
#include <iostream>
int main(int argc, char** argv) {
std::cout << "round(0.5):\t" << round(0.5) << std::endl;
std::cout << "round(-0.5):\t" << round(-0.5) << std::endl;
std::cout << "round(1.4):\t" << round(1.4) << std::endl;
std::cout << "round(-1.4):\t" << round(-1.4) << std::endl;
std::cout << "round(1.6):\t" << round(1.6) << std::endl;
std::cout << "round(-1.6):\t" << round(-1.6) << std::endl;
return 0;
}
Output:
round(0.5): 1
round(-0.5): -1
round(1.4): 1
round(-1.4): -1
round(1.6): 2
round(-1.6): -2
Problem
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??