title: Difference between a virtual function and a pure virtual function
body: <p>What is the difference between a pure virtual function and a virtual function? </p>
  
  <p>I know "Pure Virtual Function is a Virtual function with no body", but what does this mean and what is actually done by the line below:</p>
  
  <pre><code>virtual void virtualfunctioname() = 0
  </code></pre>