title: C++: Bad practice to use friend classes instead of writing getters / setters?
body: <p>I have two classes which in one aspect work together tightly. They both use functionality of each other that should be only used by them and not by any other class.</p>
  
  <ul>
  <li>Is it bad practice if I make those two classes friends so they can directly access and manipulate member variables of each other, without using any getter / setter functions?</li>
  </ul>