Simple scope based code execution time printer.

time_it.hpp

#include <chrono>
#include <iostream>
#include <string>

class TimeIt {
private:
  std::string m_name;
  std::chrono::time_point<std::chrono::high_resolution_clock> m_beg;
  
public:
  explicit TimeIt(std::string name) : m_name(std::move(name)), m_beg(std::chrono::high_resolution_clock::now()) {
    std::cout << m_name << ": Starting" << std::endl;
  }

  ~TimeIt() {
    auto end = std::chrono::high_resolution_clock::now();
    
    // Timings in release are on a different scale.
#ifdef NDEBUG
    auto dur = std::chrono::duration_cast<std::chrono::milliseconds>(end - m_beg);
    std::cout << m_name << ": " << dur.count() << " ms" << std::endl;
#else
    auto dur = std::chrono::duration_cast<std::chrono::seconds>(end - m_beg);
    std::cout << m_name << ": " << dur.count() << " s" << std::endl;
#endif
  }
};