Calculate time difference

[Troix]

Hello!

I would like to calcualte the time difference:

 #include <iostream>
#include <chrono>

int main()
{

    using std::chrono::system_clock;
    using std::chrono::milliseconds;
    using std::chrono::nanoseconds;
    using std::chrono::duration_cast;

    std::chrono::seconds sec(1);

    const auto duration = milliseconds(100);
    const auto start = system_clock::now();
    std::cout << "Hello\n";
    std::cout << "Hello\n";
    std::cout << "Hello\n";
    std::cout << "Hello\n";
    std::cout << "Hello\n";
    const auto stop = system_clock::now();
    const auto d_correct = duration_cast<nanoseconds>(duration).count();
    const auto d_actual = duration_cast<nanoseconds>(stop - start).count();
    std::cout << d_actual;

}

There I get a zero value.
How do I get the decimal digits?

Thx,
Troix

[48T7M4Gy]

http://en.cppreference.com/w/cpp/chrono/duration