Inheritance or composition? (optional)

Referring to the previous example, it is clear that realizing the class Student2 instead of Student is a questionable choice. So, when is it reasonable to use composition?

In general, we can adopt the following criteria:

• If each object of X is an object of Y (X IS-A Y), then we use inheritance.
• If each object of Y has an object of X (Y HAS-A X), then we use composition.

These aspects will be studied in later courses.