#include <condition_variable>

#include <mutex>

#include <future>

#include <iostream>

#include <thread>

#include <queue>

using namespace std;

queue<int> q;

mutex queueMutex;

condition_variable queueCondVar;

void provider(int val)

{

    for (int i = ; i < ; ++i)

    {

        {

            this_thread::sleep_for(chrono::milliseconds());

            cout << "\nWait\n";

            this_thread::sleep_for(chrono::milliseconds());

            lock_guard<mutex> lg(queueMutex);

            q.push(val + i);

        }

        queueCondVar.notify_one();

        //this_thread::sleep_for(chrono::milliseconds(val));

    }

}

void consumer(int num)

{

    while (true)

    {

        int val;

        {

            unique_lock<mutex> ul(queueMutex);

            queueCondVar.wait(ul, []{return !q.empty(); });

            val = q.front();

            q.pop();

        }

        cout << "consumer" << num << ":" << val << endl;

    }

}

int main()

{

    auto p1 = async(launch::async, provider, );

    auto p2 = async(launch::async, provider, );

    auto p3 = async(launch::async, provider, );

    auto c1 = async(launch::async, consumer, );    //this_thread::sleep_for(chrono::milliseconds(5000));

    auto c2 = async(launch::async, consumer, );

    //system("pause");

    p1.get();

    p2.get();

    p3.get();

    c1.get();

    c2.get();

    return ;

}