aaa.cpp

#include <cstdlib>
#include <iostream>
#include <chrono>
#include <random>

template <typename Fn>
void measure(Fn &&fn) {
  auto before = std::chrono::system_clock::now();
  auto res = std::forward<Fn>(fn)();
  auto after = std::chrono::system_clock::now();
  auto time = std::chrono::duration_cast<std::chrono::milliseconds>(after - before);

  std::cout << "Elapsed: " << time.count() << '\n';
  std::cout << "Result: " << res << '\n';
  std::cout << std::flush;
}

int main() {
  std::srand(std::time(0));

  measure([]() {
    uint64_t sum_1 = 0;
    for (uint64_t i = 0; i < (COUNT); i++) {
      sum_1 += std::rand() % 101;
    }
    return sum_1;
  });

  measure([=]() {
    uint64_t sum_2 = 0;
    std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int32_t> distr{0, 100};
    for (uint64_t i = 0; i < (COUNT); i++) {
      sum_2 += distr(rng);
    }
    return sum_2;
  });

  measure([]() {
    uint64_t sum_2 = 0;
    std::minstd_rand rng{std::random_device{}()};
    std::uniform_int_distribution<int32_t> distr{0, 100};
    for (uint64_t i = 0; i < (COUNT); i++) {
      sum_2 += distr(rng);
    }
    return sum_2;
  });
}