This program can display the list of students and some of their personal information such as name, student id and department. It also can display their scores and average scores, then determine whether that student can enter a list of elective courses from their score requirement.
The main difference between abstract class and interface is that interface can only contain abstract methods (no body), while abstract classes can contain both abstract and non-abstract methods. The difference in implementing abstract and interface is that abstract uses "extends" while interface uses "implements". Interface can also have a class inheriting multiple interfaces, while classes can only inherit one abstract class.