class IndexError {};


class Vector {
	int capacity_;
	int size_;
	int *buffer_;
public:
	Vector (int capacity=10): capacity_(capacity), size_(capacity) {
		buffer_ = new int[capacity];
	}

	~Vector () {
		delete [] buffer_;
	}

	int size() const {
		return size_;
	}

	bool empty() const {
		return size_ == 0;
	}

	int &index(n) const {
		if (n < 0 || n > size_)
                        throw IndexError();
                return buffer_[n];
	}

	int &operator [](int n) {
		return index(n);
	}

        const int &operator [](int n) const {
                return index(n);

        }

	void clear() {
		size_ = 0;
	}

	int capacity() const {
		return capacity_;
	}

	int &front() {
		if (empty())
			throw IndexError();
		return buffer_[0];
	}

	const int &front() const {
		return front();
	}


};