/ @location: an index to a location in the sequence. // @returns the point at @location. // const version. // abort() if out-of-range. const std::array& operator[](size_t location) const { // Code missing. }

// @c1: A sequence. // @c2: A second sequence. // @return their sum. If the sequences are not of the same size, append the // result with the remaining part of the larger sequence. friend Points2 operator+(const Points2 &c1, const Points2 &c2) { // Code missing. }

// Overloading the << operator. friend std::ostream &operator<<(std::ostream &out, const Points2 &some_points2) { // Code missing. } private: // Sequence of points. std::array *sequence_; // Size of sequence. size_t size_;