//----------------------------------------------------------------------------
// StackInterface.java           by Dale/Joyce/Weems                Appendix F
//
// Interface for a class that implements a stack.
// A stack is a last in, first out structure.
//----------------------------------------------------------------------------

 

public interface StackInterface<T>

{
  void pop() throws StackUnderflowException;
  // Throws StackUnderflowException if this stack is empty;
  // otherwise, removes top element from this stack.
  
  T top() throws StackUnderflowException;
  // Throws StackUnderflowException if this stack is empty;
  // otherwise, returns top element from this stack.
  
  boolean isEmpty();
  // Returns true if this stack is empty; otherwise, returns false.
}