title: Derived Class (Pure virtual C++)
body: <p>I have problem using class base with pure virtual method.
  The method should be virtual.</p>
  
  <p>I get this error:</p>
  
  <pre><code>Error: object of abstract class type "Membro" is not allowed: function "Membro::mensalidade" is a pure virtual function
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/0KDUS.png" alt="enter image description here"></p>
  
  <p>Anyone can help?</p>
  
  <p>Thanks!</p>