{

using namespace std::chrono_literals;

int sum{};

for (int i = 0; i < count; ++i)

{

sum += i;

std::cout << '.';

std::this_thread::sleep_for(300ms); // std::chrono::seconds(1)

}

return sum;

{

using namespace std::chrono_literals;

std::future<int> result = std::async(std::launch::async, Operation, 10);

std::this_thread::sleep_for(1s);

std::cout << "main() thread continues execution...\n";

if (result.valid())

{

auto timepoint = std::chrono::system_clock::now();

timepoint += 1s;

auto status = result.wait_until(timepoint);

// auto status = result.wait_for(4s) ;

switch (status)

{

case std::future_status::deferred:

std::cout << "Task is synchronous\n";

break;

case std::future_status::ready:

std::cout << "Result is ready\n";

break;

case std::future_status::timeout:

std::cout << "Task is still running\n";

break;

}

// result.wait() ;

// Operation(10) ;

auto sum = result.get();

std::cout << sum << std::endl;

}

}