title: What are coroutines in C++20?
body: <p>What are coroutines in <a href="/questions/tagged/c%2b%2b20" class="post-tag" title="show questions tagged &#39;c++20&#39;" rel="tag">c++20</a>?</p>
  
  <p>In what ways it is different from "Parallelism2" or/and "Concurrency2" (look into below image)?</p>
  
  <p>The below image is from ISOCPP.</p>
  
  <p><a href="https://isocpp.org/files/img/wg21-timeline-2017-03.png" rel="noreferrer">https://isocpp.org/files/img/wg21-timeline-2017-03.png</a></p>
  
  <p><a href="https://i.stack.imgur.com/4MtgA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4MtgA.png" alt="enter image description here"></a></p>