#include <iostream>
#include <string>

void print(double d)
{
    std::cout << std::to_string(d) << std::endl;
    printf("%f\n", d);
    std::cout << d << std::endl;
    printf("%e\n", d);
    printf("%g\n", d);
}

int main()
{
    double d = 0.0000001;
    print(d);
    d = 1 / 0.5;
    std::cout << std::endl;
    print(d);
}