#include <chrono>


struct Timer
{
  std::chrono::steady_clock::time_point start_t;
  std::chrono::steady_clock::time_point end_t;
  std::chrono::nanoseconds dur;
  void start();
  void stop();
  void reset();
  void print(const char * str);
  void stop_and_print(const char * str);
  void reset_and_start();
};