Why can't I make a vector of references?

Question

When I do this:

std::vector hello;

Everything works great. However, when I make it a vector of references instead:

Answer 1

The component type of containers like vectors must be assignable. References are not assignable (you can only initialize them once when they are declared, and you cannot make them reference something else later). Other non-assignable types are also not allowed as components of containers, e.g. vector is not allowed.