title: What do "&" and "*" in front parameter mean?
body: <p>I realize that these may be beginner questions, but to properly understand concepts, I'd appreciate solid answer or a link towards documentation.  </p>
  
  <p>What is the meaning of <code>&amp;</code> or <code>*</code> in front of parameter names, or after datatypes within C++ functions?</p>
  
  <p><strong>For example:</strong></p>
  
  <p><code>void ApplicationUI::requestFinished(QNetworkReply* reply) { //... }</code></p>
  
  <p>or</p>
  
  <p><code>void PostHttp::post(const QString &amp;body) { //... }</code></p>
  
  <p><strong>Bonus question</strong>
  In the post function above... does <code>const</code> make it required for this function pass constant variable or is there a different reason for it?</p>