public static Trainers createTrainer()
        {
            Console.WriteLine("Please give the First Name of the trainer.");
            string firstName = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Last Name of the trainer.");
            string lastName = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Subject of the trainer.");
            string subject = Helper.noEmptyStringInputChecker();

            Trainers trainer = new Trainers(firstName, lastName, subject);

            HelperDB.addToDb(trainer);
            return(trainer);
        }
        public static Students createStudent()
        {
            Console.WriteLine("Please give the First Name of the student.");
            string firstName = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Last Name of the student.");
            string lastName = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the birth date of the student. (DD/MM/YYYY)");
            DateTime birthDate = Helper.validDateTimeInput(new DateTime(2020 - 120, 01, 01), DateTime.Now);

            Console.WriteLine("Please give the tuition fees of the student.");
            decimal tuitionFees = Helper.decimalInput(0, 9999.99m);

            Students student = new Students(firstName, lastName, birthDate, tuitionFees);

            HelperDB.addToDb(student);
            return(student);
        }
        public static Assignments createAssignment(Courses course)
        {
            Console.WriteLine("Please give the Title of the assignment.");
            string title = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Description of the assignment.");
            string description = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the SubDate of the assignment. (DD/MM/YYYY)");
            DateTime subDate = Helper.validDateTimeInput(course.start_date, course.end_date, true);

            Console.WriteLine("Please give the oralMark of the assignment, as an integer between 1 and 100.");
            int oralMark = Helper.intInput(1, 100);

            Console.WriteLine("Please give the totalMark of the assignment, as an integer between 1 and 100.");
            int totalMark = Helper.intInput(1, 100);

            Assignments assignment = new Assignments(title, description, subDate, oralMark, totalMark);

            HelperDB.addToDb(assignment);
            return(assignment);
        }
        public static Courses createCourse()
        {
            Console.WriteLine("Please give the Title of the course.");
            string title = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Stream of the course.");
            string stream = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Type of the course.");
            string type = Helper.noEmptyStringInputChecker();

            Console.WriteLine("Please give the Start Date of the course. (DD/MM/YYYY)");
            DateTime startDate = Helper.validDateTimeInput(new DateTime(1753, 01, 01), new DateTime(9999, 12, 31));

            Console.WriteLine("Please give the End Date of the course. (DD/MM/YYYY)");
            DateTime endDate = Helper.validDateTimeInput(startDate, new DateTime(9999, 12, 31));

            Courses course = new Courses(title, stream, type, startDate, endDate);

            HelperDB.addToDb(course);
            return(course);
        }