public List<Course> GetAllUnscheduledCourses(Course aCourse)
        {
            List<Course> unscheduleCourseList = new List<Course>();
            aCourseGateway = new CourseGateway();
            List<Course> courseList = new List<Course>();
            courseList = aCourseGateway.GetAllCoursesByDepartment(aCourse.ADepartment.DepartmentId,
                                                                  aCourse.ASemester.SemesterId);
            List<int> coursesId = new List<int>();
            int status;
            coursesId = aCourseGateway.GetScheduleCoursesId(aCourse);
            foreach (Course course in courseList)
            {
                status = 0;
                foreach (int courseId in coursesId)
                {
                    if (courseId == course.CourseId)
                    {
                        status = 1;
                    }

                }
                if (status == 0)
                {
                    unscheduleCourseList.Add(course);
                }
            }
            return unscheduleCourseList;
        }
 public List<Course> GetAllCoursesByDepartment(int departmentId, int semesteId)
 {
     aCourseGateway = new CourseGateway();
     return aCourseGateway.GetAllCoursesByDepartment(departmentId, semesteId);
 }