title: What is a public interface?
body: <p><em>"Using only the public interface of the linked list class, write a method
      public static void reverse(LinkedList staff)
  that reverses the entries in a linked list."</em></p>
  
  <p>The part of all of that I'm not understanding is the first part. What does it mean by public interface of linked list class? Do I create a new class file that starts with something like <em>public interface linkedlist</em>? Can I add the method as a inner class within my main class? </p>