Round half to even implementation for float

roundHalfToEven.cpp

#include <array>
#include <cmath>
#include <iostream>

float roundHalfToEven(float f)
{
    const float r = round(f); // Result is round-half-away-from-zero
    const float d = r - f; // Difference

    // Result is not half, RHAFZ result same as RHTE
    if ((d != 0.5f) && (d != -0.5f))
    {
        return r;
    }

    // Check if RHAFZ result is even, then RHAFZ result same as RHTE
    if (fmod(r, 2.0f) == 0.0f)
    {
        return r;
    }

    // Switch to even value
    return f - d;
}

int main()
{
    const std::array<float, 8> fvals {{-5.5, -4.5, -3.5, -0.5, 0.5, 3.5, 4.5, 5.5}};

    for (float f : fvals)
    {
        const float r = roundHalfToEven(f);
        std::cout << "roundHalfToEven(" << f << "): " << r << std::endl;
    }

    return 0;
}