#include <new.h>
//#include <bool.h>
class node {		// class node outside Istack, needs friend
	friend class Istack;
	int data;
	node* next;
	node(int, node* ); 	// constructor prototype
};

class Istack {		// linked list implementation
	node* top;
public:
	void init(int Nitems = 100) { top = NULL; }
	void push(int x) { top = new node(x, top); }
	int pop();			// Not defined here, later
	bool isempty() { return( top == NULL ); }
	bool isfull() { return( FALSE ); }	// Never Full
};