interface/abstract class
<p>i have read some lines from somewhere but i cant understand the meaning of this line clearly .. i dont know why i cant understand. I know the difference between this two very well.. But plz help me .. and explain that what it does mean... ?</p>

<blockquote>
  <p><strong>In design, you want the base class to present only an interface for its
  derived classes. This means, you don’t
  want anyone to actually instantiate an
  object of the base class. You only
  want to upcast to it (implicit
  upcasting, which gives you polymorphic
  behaviour), so that its interface can
  be used. This is accomplished by
  making that class abstract using the
  abstract keyword. If anyone tries to
  make an object of an abstract class,
  the compiler prevents it.</strong></p>
</blockquote>

<p>Thanks in advance....</p>
