//Vstack.h////////////
#ifndef FALSE
#define FALSE 0
#endif
#ifndef NULL
#define NULL 0
#endif

#ifndef TONYSTACK
#define TONYSTACK 1
template<class T>
    class Gstack {
    public:
    	virtual void push(T) = 0; 	// pure virtual function
    	virtual T pop() = 0; 		// pure virtual function
    	virtual bool isempty() = 0;	// pure virtual function
    	virtual bool isfull() = 0; 	// pure virtual function
    };
#endif
//AStack.h///////////
//#include "Vstack.h"
#ifndef TONYASTACK
#define TONYASTACK 1
template<class T>
    class Array_stack : public Gstack<T> {
    	int sz;
    	int top;
    	T* astack;
    public:
    	Array_stack(int );
    	Array_stack();
    	~Array_stack();
		void push(T );
    	T pop();
    	bool isempty(); 
    	bool isfull(); 
    };
#endif
//LStack.h////////////
//#include "Vstack.h"
#ifndef TONYLSTACK
#define TONYLSTACK 1
template<class T>
    class Link_stack : public Gstack<T> {
    	struct node {
    		T data;
    		node* next;
    		node(T d, node* n) 
    			{ data = d; next = n; }
    	};
    	node* top;
    public:
    	Link_stack( );
    	void push(T );
    	T pop();
    	bool isempty() ;
    	bool isfull() ;
    };
#endif
//ArrayStack.cc//////////
#include <assert.h>
//#include "Astack.h"

template<class T>
	Array_stack<T> :: Array_stack (int Nitems)
            { sz = Nitems; astack = new T[sz]; top = sz; };
template<class T>
	Array_stack<T> :: Array_stack ()
            { sz = 100; astack = new T[sz]; top = sz; };
template<class T>
	Array_stack<T> :: ~Array_stack ()
    		{ delete[] astack; }
template<class T>
	void Array_stack<T> :: push (T x)
   		    { assert( !isfull() ); astack[--top] = x; }
template<class T>
	T Array_stack<T> :: pop()
    		{ assert( !isempty() ); return( astack[top++] ); }
template<class T>
	bool Array_stack<T> :: isempty()
    		{ return( top == sz ); }
template<class T>
	bool Array_stack<T> :: isfull ()
            { return( top == 0 ); }
//LinkStack.cc///////////
#include <assert.h>
//#include "Lstack.h"

template<class T> 
	Link_stack<T> :: Link_stack(  ) 
    		{ top = NULL; }
template<class T>
	void Link_stack<T> :: push(T x)
    		{ top = new node(x, top); }
template<class T>
	T Link_stack<T> :: pop() {
        		assert( !isempty() );
        		T t = top -> data;
        		node* oldtop = top;
        		top = top -> next;
        		delete oldtop;
        		return t;
    	}
template<class T>
	bool Link_stack<T> :: isempty() 
    		{ return( top == NULL ); }
template<class T>
	bool Link_stack<T> :: isfull() 
    		{ return( FALSE ); }
//Reverse.cc/////////
#include <iostream.h>
//#include "Vstack.h"
// Doesn't know about Arraystack or Linkedstack
void reverse( Gstack<int>&, int );	// a prototype

void reverse( Gstack<int> &s, int n )
{
        int i;

        for( i = 0; i < n; i++ ) {
                s.push(i);
        }
        for( i = 0; i < n; i++ ) {
                cout << s.pop() << ' ';
        }
        cout << endl;
}

//    This is Main.cc
//#include "Vstack.h"
//#include "Astack.h"
//#include "Lstack.h"
//extern void reverse( Gstack<int> &s, int n );

int main()
{
	Array_stack<int> s1(500);
	Link_stack<int> s2;	// but not s2();
//	Array_stack<char> s3;
//	Link_stack<char> s4;

	reverse (s1, 20);
	reverse (s2, 20);
//	reverse (s3, 20);	//problem reverse only knows about integers
//	reverse (s4, 20);	//need to make reverse a member function, perhaps?
	return 0;
}
/*
19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 
19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 
*/
/*
Main.cc:8: warning: return type for `main' changed to integer type
Astack.h:18: warning: `class Array_stack<int>' has virtual functions but
non-virtual destructor
Astack.h:18: warning: `class Array_stack<char>' has virtual functions
but non-virtual destructor
Main.cc: In function `int main(...)':
Main.cc:12: warning: unused variable `class Link_stack<char> s4'
Undefined                       first referenced
 symbol                             in file
cout                                /var/tmp/cca000WA4.o
__ls__7ostreamPFR7ostream_R7ostream /var/tmp/cca000WA4.o
endl__FR7ostream                    /var/tmp/cca000WA4.o
__ls__7ostreamc                     /var/tmp/cca000WA4.o
__ls__7ostreami                     /var/tmp/cca000WA4.o
ld: fatal: Symbol referencing errors. No output written to a.out

*/