#include <cmath>
#include <cfenv>
#include <iostream>
 
int main()
{ 
  for (auto mode : {FE_TONEAREST, FE_TOWARDZERO, FE_DOWNWARD, FE_UPWARD})
  {
    std::fesetround(mode);
    std::cout << "Rundungsmodus: " << mode << "\nx\tround\trint\tnearby\n";

    for (double x : { -3.5, -2.5, -1.5, -0.5, 0.5, 1.5, 2.5, 3.5 })
    {
      std::cout << x << '\t'
        << std::round(x) << '\t'      // round .5 away from zero (aufrunden)    
        << std::rint(x) << '\t'       // round .5 to nearest even (zur nächsten geraden Zahl)
        << std::nearbyint(x) << '\n'; // in IEEE 754 default mode FE_TONEAREST
    }
  }	
}