Multi threading in C++17

mt.cpp

#include <iostream>
#include <chrono>
#include <string>
#include <thread>
#include <atomic>
#include <vector>
#include <queue>
#include <mutex>
#include <condition_variable>

using namespace std::literals::chrono_literals;
std::atomic should_stop{false};

struct WorkerData {
  std::queue<int> q;
  std::mutex mtx;
  std::condition_variable cond;
};

void WorkerFunc(WorkerData& wd, std::chrono::milliseconds sleep_duration) {
  while (!should_stop) {
    int data{0};

    {
      std::unique_lock lk{wd.mtx};
      wd.cond.wait(lk, [&] { return !wd.q.empty() || should_stop; });
      if (should_stop) {
        break;
      }

      data = wd.q.front();
      wd.q.pop();
    }

    std::cout << "Worker(" << std::this_thread::get_id() << "): "
              << "Process data " << data
              << ", and sleep " << sleep_duration.count() << " msecs"
              << std::endl;

    std::this_thread::sleep_for(sleep_duration);
  }
}

int main() {
  std::vector<std::thread> threads;

  WorkerData wd;
  threads.emplace_back(WorkerFunc, std::ref(wd), 200ms);
  threads.emplace_back(WorkerFunc, std::ref(wd), 70ms);

  while (!std::cin.eof()) {
    int data{0};
    std::cin >> data;
    if (data == -1) {
      break;
    }

    {
      std::lock_guard lk{wd.mtx};
      wd.q.push(data);
    }

    wd.cond.notify_one();
  }

  while (true) {
    {
      std::lock_guard lk{wd.mtx};
      if (wd.q.empty()) {
        break;
      }
    }

    std::cout << "[main thread] sleeping 1000 msec" << std::endl;
    std::this_thread::sleep_for(1'000ms);
  }

  should_stop = true;
  wd.cond.notify_all();

  for (auto& t : threads) {
    t.join();
  }
}