#ifndef POINTERH
#define POINTERH
#include <iostream>
#include <iterator>	//for classes iterator and input_iterator_tag 
using namespace std;

class pointer: public iterator<input_iterator_tag, int> {
	istream *istr;
	bool ok;	//true if not yet at end of file
	int i;
	void read() {if (ok) {ok = *istr >> i;}}
public:
	pointer(istream& initial_istr): istr(&initial_istr), ok(true) {read();}
	pointer(): istr(0), ok(false) {}
	const int operator*() const {return i;}
	pointer& operator++() {read(); return *this;}	//prefix

	friend bool operator==(const pointer& p1, const pointer& p2) {
		return p1.ok == p2.ok && (!p1.ok || p1.istr == p2.istr);
	}
};

inline const pointer operator++(pointer& p, int)	//postfix
{
	const pointer old = p;
	++p;		//p.operator++()
	return p;
}

inline bool operator!=(const pointer& p1, const pointer& p2)
{
	return !(p1 == p2);
}

#endif