public Grade?GetStudentAverageGradePerCourse(Course course)
{
studentService = new StudentService();
subjectService = new SubjectService();
studentSubjectService = new StudentSubjectService();
gradeService = new GradeService();
int studentsAverageGrade;
int studentsAverageRounded;
Grade?averageGrade;
List <Subject> subjectsFromACourse = subjectService.GetSubjectsFromACourse(course);
int numberOfSubjectsInACourse = subjectsFromACourse.Count();
int numberOfStudentsRegisteredInACourse = studentService
.GetStudentsRegisteredInACourse(course).Count();
int studentsTotalGrades = studentSubjectService
.GetTotalStudentGradesFromACourse(course);
int numberOfStudentSubjectsGraded = GetNumberOfStudentsSubjectsGradedInACourse(subjectsFromACourse);
if (numberOfSubjectsInACourse != 0 && numberOfStudentSubjectsGraded != 0)
{
studentsAverageGrade =
studentsTotalGrades / numberOfStudentSubjectsGraded;
}
else
{
studentsAverageGrade = 0;
}
studentsAverageRounded = (int)Math.Round((decimal)studentsAverageGrade);
averageGrade = gradeService.ConvertIntToGrade(studentsAverageRounded);
return(averageGrade);
}
