// Stack class interface: array implementation
//
// Etype: must have zero-parameter constructor and operator=
// CONSTRUCTION: with (a) no initializer;
//     copy construction of Stack objects is DISALLOWED
// Deep copy is not supported
//
// ******************PUBLIC OPERATIONS*********************
// void Push( Etype X )   --> Insert X
// void Pop( )            --> Remove most recently inserted item
// Etype Top( )           --> Return most recently inserted item
// int IsEmpty( )         --> Return 1 if empty; else return 0
// void MakeEmpty( )      --> Remove all items
// ******************ERRORS********************************
// Predefined exception is propogated if new fails
// EXCEPTION is called for Top or Pop on empty stack

#ifndef __Stack_H
#define __Stack_H

#include "Vector.h"

template <class Etype>
class Stack
{
  public:
    Stack( ) : Array( 5 ), TopOfStack( -1 ) { }
    ~Stack( ) { }

    void Push( const Etype & X );
    void Pop( );
    const Etype & Top( ) const;
    int IsEmpty( ) const { return TopOfStack == -1; }
    void MakeEmpty( )    { TopOfStack = -1; }

  private:
    // Copy constructor disabled because of Vector
    // Disable operator=
    const Stack & operator=( const Stack & Rhs )
        { return *this; }

    int TopOfStack;
    Vector<Etype> Array;
};
#endif