Review beginners exercises Day 2

[chavid]

@ALL If the ExerciceSchedule_EssentialCourse.md is up to date, Day 2, there is an exercise about virtual inheritance which seems to me completely irrelevant for beginners. On the contrary, something about object-functions (operator()) would help a lot for the template/stl exercises of Day 3. Either it deserves its own exercise, or it should be integrated in the operators exercise. For example, we may transform printAndCheck() into an object-function which store the maximum title length as a member variable (currently 40).

[chavid]

Actually, it lacks at the beginning of Day 2 an exercise about the creation of a simple class. That may be Fracrion, without the operators...

[chavid]

@ALL, my proposal:

• extract from current "operators" the creation of a class Fraction, all made with named methods and functions, a make it an introduction exercise about creating a class, with constructors, destructors, assignment.
• as a second exercise, "operators", as I suggested in About operators exercise #439, plus the operator() as said above.
• as a third exercise, "polymorphism".
• keep "virtual inheritance" at last, if you care.