#include <algorithm>
#include <iostream>
#include <limits>
#include <random>
#include <string>
#include <thread>
#include <vector>

int main(int argc, char *argv[]) {
  if (argc != 2) {
    std::cerr << "Please, give the number of values to compute in the command "
                 "line.\n";
    return 1;
  }

  int N = std::stoi(argv[1]);
  if (N <= 0) {
    std::cerr << "The number of values must be positive.\n";
    return 2;
  }

  // Random number generation.
  std::random_device rd;
  std::default_random_engine rand_gen(rd());
  std::uniform_int_distribution<> dist(0, std::numeric_limits<int>::max());

  // Create a random array of N int elements.
  std::vector<int> array(N);
  std::generate(begin(array), end(array), [&]() { return dist(rand_gen); });

  int max, min;

  std::thread calc_min([&min, &array = std::as_const(array)]() {
    min = array[0];
    for (size_t i = 1; i < array.size(); i++)
      if (array[i] < min) {
        min = array[i];
      }
  });

  std::thread calc_max([&max, &array = std::as_const(array)]() {
    max = array[0];
    for (size_t i = 1; i < array.size(); i++)
      if (array[i] > max) {
        max = array[i];
      }
  });

  calc_min.join();
  calc_max.join();

  std::cout << "Generated " << N << " random numbers." << std::endl;
  std::cout << "Largest is " << max << std::endl
            << "Smallest is " << min << std::endl;
  return 0;
}