What modifier should you use on a class so that a class in the same package can access it but a class (including a subclass) in a different package cannot access it?

Discuss the differences between the candidate keys and the primary key of a relation. Explain what is meant by a foreign key. How do foreign keys of relations relate to candidate keys? Give examples to illustrate your answer.

What will be an ideal response?

Which of the following classes is deepest in the inheritance hierarchy?

a. basic_iostream b. basic_ofstream c. basic_ifstream d. basic_fstream