The syntax is different, but in terms of what you can do, the only difference I know is that references can be reassigned.

Both give you the guarantee that it's not pointing at the NULL address. In the case of const pointers, that's because you can't reassign it, and you'd never deliberately assign a const pointer to NULL. In the case of references, it's because there's actually no such thing as a null reference in C++.

That's not the case in Java and C#, which allow "null" to be a right-hand value for all types.