#include <chrono>
 #include <iostream>
 #include <ratio>

 int main(){

   std::cout << std::endl;

   typedef std::chrono::duration<long long, std::ratio<1>> MySecondTick;

   MySecondTick aSecond(1);

   std::chrono::nanoseconds nano(aSecond);
   std::cout << nano.count() << " nanoseconds" << std::endl;

   std::chrono::microseconds micro(aSecond);
   std::cout << micro.count() << " microseconds" << std::endl;

   std::chrono::milliseconds milli(aSecond);
   std::cout << milli.count() << " milliseconds" << std::endl;

   std::chrono::seconds seconds(aSecond);
   std::cout << seconds.count() << " seconds" << std::endl;

   // std::chrono::minutes minutes(aSecond);
   std::chrono::minutes minutes(std::chrono::duration_cast<std::chrono::minutes>(aSecond));
   std::cout << minutes.count() << " minutes(truncated value)" << std::endl;

   //std::chrono::hours hours(aSecond);
   std::chrono::hours hours(std::chrono::duration_cast<std::chrono::hours>(aSecond));
   std::cout << hours.count() << " hours(truncated value)" << std::endl;

   std::cout << std::endl;

   typedef std::chrono::duration<double, std::ratio<60>> MyMinuteTick;
   MyMinuteTick myMinute(aSecond);
   std::cout << myMinute.count() << " minutes" << std::endl;

   typedef std::chrono::duration<double, std::ratio<3600>> MyHourTick;
   MyHourTick myHour(aSecond);
   std::cout << myHour.count() << " hours" << std::endl;

   typedef std::chrono::duration<double, std::ratio<2700>> MyLessonTick;
   MyLessonTick myLesson(aSecond);
   std::cout << myLesson.count() << " lessons" << std::endl;

   typedef std::chrono::duration<long long, std::ratio <1,2>>   MyHalfASecondTick;
   MyHalfASecondTick myHalfASecond(aSecond);
   std::cout << myHalfASecond.count() << " HalfASeconds" << std::endl;

   std::cout << std::endl;
 }