#ifndef STOPWATCH_H
#define STOPWATCH_H

#include <chrono>

template <typename real> class stopwatch {
public:
  void reset();
  real elapsed();

private:
  using clock = std::chrono::high_resolution_clock;
  clock::time_point t0{clock::now()};
};

template <typename real> inline void stopwatch<real>::reset() {
  t0 = clock::now();
}

template <typename real> inline real stopwatch<real>::elapsed() {
  using seconds = std::chrono::duration<real, std::ratio<1, 1>>;

  auto tnow = clock::now();
  auto duration = std::chrono::duration_cast<seconds>(tnow - t0);

  return duration.count();
}

#endif // STOPWATCH_H