Array List resize operation

arrayListResize.hpp

/**
 * Double the size of the data structure.
 *
 * @tparam T type
 */
template<typename T>
void ArrayList<T>::resize() {
    // Create the new bigger array with double the size of the old one.
    T *const newStorage = new T[_capacity *= 2];

    // Copy all the elements from the old array to the new one.
    for (int i = 0; i < _size; ++i) {
        newStorage[i] = _array[i];
    }

    // Make the bigger array to be the current array of
    // the data structure and clear the old one.
    T *oldStorage = _array;
    _array = newStorage;
    delete[] oldStorage;
}