title: open and write to existing fstream without overwrite/clearing in C++
body: <p>I have an existing txt file, I want to be able to write stuff to it (on the next line) without modifying the existing contents. What's a good way to do this?</p>
  
  <pre><code>#include &lt;iostream&gt;
  ofstream myfile ("ex.txt"); 
  </code></pre>
  
  <p>seems to clear all the existing text.</p>