The University has several Departments, these Departments have several Groups and these Groups have students who study there. Each student has several subjects with grades. It is required to implement a hierarchy of students, groups and departments.
• Calculate an average score for all subjects a certain student learns • Calculate an average score for a specific subject in a specific group and specific department • Calculate the university-wide average grade for a specific subject
Implement the following exceptions: • Score below 0 or above 10 • No subjects for a student (there must be at least one subject) • No students in the group • No groups at a department • No departments at the university