Threads vs Tasks

// asyncVersusThread.cpp
#include <future>
#include <thread>
#include <iostream>
int main(){
  std::cout << std::endl;
  int res;
  std::thread t([&]{ res = 2000 + 11; });
  t.join();
  std::cout << "res: " << res << std::endl;             
  auto fut= std::async([]{ return 2000 + 11; });
  std::cout << "fut.get(): " << fut.get() << std::endl;   
  std::cout << std::endl;   
}