title: What is the difference between an abstract class and an interface?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/761194/interface-vs-abstract-class-general-oo">Interface vs Abstract Class (general OO)</a>  </p>
  </blockquote>
  
  
  
  <p>Can I ever instantiate an Abstract class?  If so, why would I not make all my non-sealed classes abstract?</p>
  
  <p>If I can't instantiate it, then what is the difference from an interface?  Can the abstract class have "base" class functionality?  Is there more to the difference between an interface and an abstract class than that?</p>