IntArray& operator=(const IntArray &array)
    {
        std::cout << "Start =\n";
        if(this == &array)
            return *this;
        delete [] arr;
        size = array.size;
        arr = new int[size];
        for(int i = 0; i < size; ++i)
        {
            arr[i] = array[i];
        }
        std::cout << "End =\n";
        return *this;
    }