void TextView::Update(Observable* o_val)
{
	Sphere *sphere = (Sphere*)o_val;
	cout << "The radius of the sphere is " << sphere->GetRadius() << endl;
	cout << "The area of the sphere is " << sphere->GetArea() << endl;
	cout << "The volume of the sphere is " << sphere->GetVolume() << endl;
}
static void sphereTest1()
{
    Sphere s;

    s.radius = 1.0f;
    //s.SetVolume(4.18879f);
    //s.SetArea(12.5664f);

    // print information
    std::cout.precision(10);
    std::cout << "--- Sphere ---" << std::endl;
    std::cout << "Radius: " << s.radius << std::endl;
    std::cout << "Volume: " << s.GetVolume() << std::endl;
    std::cout << "Area: " << s.GetArea() << std::endl;
}