title: Using both Inheritance and Composition in the same class?
body: <p>I know the rule of using inheritance when there is an is-a relationship, and composition when there's a has-a relationship, but are the two mutually exclusive/replacements for one another or would there be a case where you should use both in the same class?</p>
  
  <p>I've Googled a lot but only found articles explaining when you use each, rather than both.</p>
  
  <p>Thanks</p>