{

double a1[4] = {1.2,2.3,3.4,4.5};

vector<double> a2(4);

a2[0] = 1.0/3.0;

a2[1] = 1.0/5.0;

a2[2] = 1.0/7.0;

a2[3] = 1.0/9.0;

array<double, 4> a3 = {3.14, 2.72, 1.61, 1.41};

array<double, 4> a4;

a4 = a3;

std::cout << "a1[2]: " << a1[2] << " at " << &a1[2] << std::endl;

std::cout << "a2[2]: " << a2[2] << " at " << &a2[2] << std::endl;

std::cout << "a3[2]: " << a3[2] << " at " << &a3[2] << std::endl;

std::cout << "a4[2]: " << a4[2] << " at " << &a4[2] << std::endl;

a1[-2] = 20.2;

std::cout << "a1[-2]: " << a1[-2] << " at " << &a1[-2] << std::endl;

std::cout << "a3[2]: " << a3[2] << " at " << &a3[2] << std::endl;

std::cout << "a4[2]: " << a4[2] << " at " << &a4[2] << std::endl;

return 0;