C プログラムはどのようにして非同期コンソール入力を実装できますか?

<code class="cpp">#include <iostream>
#include <future>
#include <thread>
#include <chrono>

static std::string getAnswer()
{
    std::string answer;
    std::cin >> answer;
    return answer;
}

int main()
{
    std::chrono::seconds timeout(5);
    std::cout << "Do you even lift?" << std::endl << std::flush;
    std::string answer = "maybe"; // default to maybe
    std::future<std::string> future = std::async(getAnswer);
    if (future.wait_for(timeout) == std::future_status::ready)
        answer = future.get();

    std::cout << "the answer was: " << answer << std::endl;
    exit(0);
}</code>