{

ThreadPool pool(4);

std::vector< std::future<int> > results;

for(int i = 0; i < 8; ++i) {

results.push_back(

pool.enqueue<int>([i] {

std::cout << "hello " << i << std::endl;

std::this_thread::sleep_for(std::chrono::seconds(1));

std::cout << "world " << i << std::endl;

return i*i;

})

);

}

for(size_t i = 0;i<results.size();++i)

std::cout << results[i].get() << ' ';

std::cout << std::endl;

return 0;