title: What happens if I read a map's value where the key does not exist?
body: <pre><code>map&lt;string, string&gt; dada;
  dada["dummy"] = "papy";
  cout &lt;&lt; dada["pootoo"];
  </code></pre>
  
  <p>I'm puzzled because I don't know if it's considered undefined behaviour or not, how to know when I request a key which does not exist, do I just use find instead ?</p>