class iterator {
    private:
        Trit data;
        size_t current_index;
        TritList& list;
    public:
        explicit iterator(TritList& _list, size_t beginning_ind = 0) : list(_list) {
            current_index = beginning_ind;
            data = list[0];
        }

        iterator(const iterator& other) : list(other.list), current_index(other.current_index), data(other.data) { }
        class iterator &operator++() {
            current_index++;
            data = list[current_index];
            return *this;
        }
        class iterator operator++(int) {
            iterator yu(*this);
            operator++();
            return yu;
        }
        class iterator &operator--() {
            current_index--;
            data = list[current_index];
            return *this;
        }
        class iterator operator--(int) {
            iterator yu(*this);
            operator--();
            return yu;
        }
        bool operator==(const iterator& other) const {
            return (other.current_index == current_index) && (other.data == data);
        }
        bool operator!=(const iterator& other) const {
            return !(*this == other);
        }
        const Trit &operator*() {
            return list[current_index];
        }
    };

    iterator begin() {
        iterator tmp(*this);
        return tmp;
    }
    iterator end() {
        iterator tmp(*this, capacity());
        return tmp;
    }