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

std::vector<int> global_queue;
std::mutex global_mutex;
std::condition_variable global_queue_cv;

int get_from_queue
 
()
{
    std::unique_lock<std::mutex> lock(global_mutex);
    std::cout << "get_from_queue: before loop, is_locked " << lock.owns_lock() << std::endl;
    while (global_queue.empty())
    {
        global_queue_cv.wait(lock);
        std::cout << "get_from_queue: inloop, is_locked "
 
 << lock.owns_lock() << std::endl;
    }
    std::cout << "get_from_queue: fater wait, is_locked " << lock.owns_lock() << std::endl;
    auto v = global_queue.back();
    global_queue.pop_back();
    return v;
}

void put_in_queue(int v)
{
    std::unique_lock<std::mutex>
 
 lock(global_mutex);
    std::cout << "put_in_queue: is_locked " << lock.owns_lock() << std::endl;
    global_queue.push_back(v);
    global_queue_cv.notify_all();
    std::cout << "put_in_queue: after notify_all, is_locked " << lock.owns_lock() << std::endl;
}

void get_thread()
{
    for (int i = 0; i < 10; ++i)
    {
        auto v = get_from_queue();
        std::cout << "get_thread : v = " << v << std::endl << std::endl << std::endl<< std::endl;
    }
}

void put_thread()
{
    for (int i = 0; i < 10; ++i)
    {
        std::this_thread::sleep_for(std::chrono::seconds(1));
        int v = i + 100;
        put_in_queue(v);
        std::cout << "put_thread : v = " << v << std::endl << std::endl << std::endl<< std::endl;
    }
}

int main()
{
    std::thread work_get(get_thread);
    std::thread work_put(put_thread);
    work_get.join();
    work_put.join();
    return 0;
}