#include <iostream>
#include <utility>

template <typename Elem> class Vector {
	int vsize; // number of elements stored
	int asize; // size of the array
	Elem *array;

	// Invariant: vsize <= asize

public:
	Vector() : vsize(0), asize(1),
		array(new Elem[asize]) {}

	Vector(const Vector<Elem> & other) : vsize(other.vsize),
			asize(other.asize),
			array(new Elem(asize)) {
		for (int i = 0; i < vsize; i++)
			array[i] = other.array[i];
	}

	Vector<Elem> & operator=(const Vector<Elem> & other) {
		if (&other != this) {
			vsize = other.vsize;
			if (asize < vsize) {
				delete[] array;
				asize = other.asize;
				array = new Elem[asize];
			}
			for (int i = 0; i < vsize; i++)
				array[i] = other.array[i];
		}
		return *this;
	}

	void fast_swap(Vector<Elem> & other) {
		swap(vsize, other.vsize);
		swap(asize, other.asize);
		swap(array, other.array);
	}

	int size() const { return vsize; }

	Elem & operator[](int i) { return array[i]; }

	void push_back(Elem x) {
		if (vsize == asize) {
			asize *= 2;
			Elem *new_array = new Elem[asize];
			for (int i = 0; i < vsize; i++)
				new_array[i] = array[i];
			delete[] array;
			array = new_array;
		}
		array[vsize] = x;
		vsize++;
	}

	void pop_back() { vsize--; }

	typedef Elem *iterator;

	iterator begin() { return array; }
	iterator end() { return array + vsize; }
};

template <typename T>
void swap(Vector<T> & x, Vector<T> & y) {
	x.fast_swap(y);
}

int main() {
	Vector<int> v;
	v.push_back(1);
	v.push_back(2);
	v.push_back(3);
	v.push_back(4);
	v.push_back(5);
	for (int i = 0; i < v.size(); i++)
		cout << v[i] << '\n';
	for (Vector<int>::iterator p = v.begin(); p != v.end(); ++p)
		cout << *p << '\n';

	Vector<int> v2 = v;
	v2 = v;
	return 0;
}