C++11 async() and future<> allow us task based parallel programming.

async_future_example02.cpp

#include <future>
#include <iostream>
#include <vector>


int main() 
{
    std::cout << "Task parallerism using C++11 async() and future<>" << std::endl;
    
    std::cout << "Main thread id: " << std::this_thread::get_id() 
        << std::endl;

    std::vector<std::future<void>> futures;
    
    //create 20 task and store them in container

    for (int i = 0; i < 20; ++i)
    {
        auto fut = std::async([]
        {
            std::this_thread::sleep_for(std::chrono::seconds(1));
            std::cout << std::this_thread::get_id() << " ";
        });

        futures.push_back(std::move(fut));
    }
    
    //run them and wait to be completed

    std::for_each(futures.begin(), futures.end(), [](std::future<void> & fut)
    {
        fut.wait();
    });
    
    std::cout << "\n\nDone ..." << std::endl;
}

/*
output

Task parallerism using C++11 async() and future<>
Main thread id: 680
7864 7524 5352 6396 34884212 2820 7956 3928 6836  7284 7576 6248 2752 7316 464 5847424  7692 1640

Done ...
계속하려면 아무 키나 누르십시오 . . .

*/