Simple time measurement class. Useful for finding how long a function/a scope runs.

timer.cpp

#include <iostream>
#include <array>
#include <chrono>
#include <string>
#include <ctime>
#include <cstdlib>

class timer {
private:
  const std::chrono::system_clock::time_point start;
  const std::string functionName;
  std::ostream &stream;

public:
  timer(const std::string &_f, std::ostream &_s = std::cout)
      : start(std::chrono::system_clock::now()), functionName(_f), stream(_s) {}
  timer(std::ostream &_s = std::cout)
      : start(std::chrono::system_clock::now()), stream(_s),
        functionName("<unknown>"){};

  ~timer() {
    auto end = std::chrono::system_clock::now();
    stream << functionName << " took "
           << std::chrono::duration_cast<std::chrono::milliseconds>(end - start)
                  .count()
           << "ms." << std::endl;
  }
};

int function();

int main(char **, int) {
  function();

  system("pause");
}

int function() {
  timer t(__FUNCTION__);

  std::srand(time(0));
  for (int i = 0; i < 1000000; i++) {
    int rand = std::rand() % 1000;
  }

  return 0;
}