#include <new.h>
//#include <bool.h>

class Istack {
	class node {
	public:
		int data;
		node* next;
	};
	node* new_node(int , node* );	// prototype only
	node* top;
public:
	// Note pop() is a prototype
	void init(int Nitems = 100) { top = NULL; }
	void push(int x) { top = new_node(x, top); }
	int pop(); // prototype function
	bool isempty() { return( top == NULL ); }
	bool isfull() { return( FALSE ); }
};