#include <iostream>
#include <stdint.h>
#include <iomanip>
 
template<typename float_t, typename int_t>
float_t machine_eps()
{
        union
        {
                float_t f;
                int_t   i;
        } one, one_plus, little, last_little;
 
        one.f    = 1.0;
        little.f = 1.0;
        last_little.f = little.f;
 
        while(true)
        {
                one_plus.f = one.f;
                one_plus.f += little.f;
 
                if( one.i != one_plus.i )
                {
                        last_little.f = little.f;
                        little.f /= 2.0;
                }
                else
                {
                        return last_little.f;
                }
        }
}
 
int main()
{
        std::cout << "machine epsilon:\n";
        std::cout << "float: " << std::setprecision(18)<< machine_eps<float, uint32_t>() << std::endl;
        std::cout << "double: " << std::setprecision(18) << machine_eps<double, uint64_t>() << std::endl;
}