private void stud(String name, String number) {
        int matNumber;
        if (tutor == null) {
            System.err.println("Error! No tutor selected.");
            return;
        }
        try {
            matNumber = Integer.parseInt(number);
        } catch (RuntimeException e) {
            System.err.println("Error! Matriculation number argument is not a number.");
            return;
        }
        //Verify number is inside specified value range: 5 digit number
        if (!(9999 < matNumber && matNumber < 100000)) {
            System.err.println("Error! Matriculation number not inside specified parameters: 5 digit number.");
            return;
        }
        if (!database.addStudent(new Student(tutor, name, matNumber))) {
            System.err.println("Error! a student with id " + matNumber + " already exists.");
        }
    }