#include <iostream>
#include <chrono>

class simTime
{
private:
  simTime(){}
  simTime( const simTime & );
  simTime& operator=( simTime );
  ~simTime(){}

  double factor_;
  size_t timeSec_;

public:
  static simTime& Instance()
  {
    static simTime instance;
    return instance;
  }

  double getFactor() {return factor_;}
  void setFactor(double factor){factor_ = factor;}

  size_t getTimeSec() {return timeSec_;}
  void setTimeSec(size_t timeSec){timeSec_ = timeSec;}
  void resetTime(){timeSec_ = 0;};
};

simTime& sT = simTime::Instance();

int main()
{
    sT.setFactor(10);
    sT.setTimeSec(0);

    std::chrono::time_point<std::chrono::system_clock> start, realTime;
    start = std::chrono::system_clock::now();

    std::chrono::duration<int> elapsed_seconds;

    while (true)
    {
        realTime = std::chrono::system_clock::now();
        std::chrono::duration<float> elapsed_seconds;
        static std::chrono::duration<float> old_elapsed_seconds(0);

        elapsed_seconds = realTime-start;
        std::time_t realTimeDuration = std::chrono::system_clock::to_time_t(realTime);

        if (elapsed_seconds.count() >= (old_elapsed_seconds.count() + 1/sT.getFactor()))
        {
            sT.setTimeSec(elapsed_seconds.count() * sT.getFactor());

            std::cout << "elapsed time: " << elapsed_seconds.count() << "s  simTime: " << sT.getTimeSec() << "s\n";
            old_elapsed_seconds = elapsed_seconds;
        }

        if (elapsed_seconds.count() > 15)
        {
            break;
        }
    }

    return 0;
}