#ifndef T_ITERATOTH
#define T_ITERATOTH
#include <cstdlib>   //for exit
#include <iterator>
#include <limits>
using namespace std;

template <class T = int, class DIFFERENCE = ptrdiff_t>
class t_iterator: public iterator<randoom_access_iterator_tag, T> {
	bool at_end;   //true if we have reached end of range
	T t;
public:
	t_iterator(): at_end(true) {}
	t_iterator(const T& initial_t): at_end(false), t(initial_t) {}

	const T& operator*() const {
		if (at_end) {
			cerr << "dereference exhausted t_iterator\n";
			exit(EXIT_FAILURE);
		}
		return t;
	}

	t_iterator& operator++() {
		if (at_end) {
			cerr << "increment exhausted t_iterator\n";
			exit(EXIT_FAILURE);
		}

		typedef numeric_limits<T> limits;   //for convenience
		if (limits::is_specialized && t == limits::max()) {
			at_end = true;
		} else {
			++t;
		}
		return *this;
	}

	friend bool operator==(const t_iterator<T, DIFFERENCE>& it1,
		               const t_iterator<T, DIFFERENCE>& it2) {
		return it1.at_end == it2.at_end &&
			(it1.at_end || it1.t == it2.t);
	}

	//etc.
};

//etc.
#endif