#pragma once
#include<iostream>
#include<string>

class Triangular_iterator
{
public:
Triangular_iterator(int index) :_index(index - 1) {}
bool operator== (const Triangular_iterator&) const;
bool operator!=(const Triangular_iterator&) const;
int operator*()const;
Triangular_iterator& operator++();
Triangular_iterator operator++(int);
//inline void check_integrity()const;

private:
inline void check_integrity()const;
int _index;
};