protected void btnSubmit_Click(object sender, EventArgs e)
    {
        if (RadioButton1.Checked)
        {
            FullTimeStudent ftStudent = new FullTimeStudent(txtName.Text);

            studentType.Add(ftStudent); // Add the student to list

            foreach (ListItem chosenCourse in CheckBoxList.Items)
            {
                // if a course is selected do the following
                if (chosenCourse.Selected)
                {
                    try
                    {
                        // Add each selected course to the student's enrolled courses
                        foreach (Course course in Helper.GetCourses())
                        {
                            if (course.ToString() == chosenCourse.Text)
                            {
                                ftStudent.addCourse(course);
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        // Display error message if courses exceed 8 hours
                        lblError.Text = ex.Message;

                        // Continue with rest of code if there is no error
                        return;
                    }
                } // End of btn selection
            }     // End of foreach

            // Display confirmation page for full-time student
            displayConfirmationPage(ftStudent);
        } // End of condition

        else if (RadioButton2.Checked)
        {
            PartTimeStudent ptStudent = new PartTimeStudent(txtName.Text);
            studentType.Add(ptStudent);

            foreach (ListItem chosenCourse in CheckBoxList.Items)
            {
                if (chosenCourse.Selected)
                {
                    try
                    {
                        foreach (Course course in Helper.GetCourses())
                        {
                            if (course.ToString() == chosenCourse.Text)
                            {
                                ptStudent.addCourse(course);
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        lblError.Text = ex.Message;
                        return;
                    }
                } // end of btn selection
            }     // end of foreach

            // Display confirmation page for part-time student
            displayConfirmationPage(ptStudent);
        } // end of condition

        else if (RadioButton3.Checked)
        {
            CoopStudent cpStudent = new CoopStudent(txtName.Text);
            studentType.Add(cpStudent);

            foreach (ListItem chosenCourse in CheckBoxList.Items)
            {
                if (chosenCourse.Selected)
                {
                    try
                    {
                        foreach (Course course in Helper.GetCourses())
                        {
                            if (course.ToString() == chosenCourse.Text)
                            {
                                cpStudent.addCourse(course);
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        lblError.Text = ex.Message;
                        return;
                    }
                } // end of btn selection
            }     // End of foreach

            // Display confirmation page for co-op student
            displayConfirmationPage(cpStudent);
        } // End of condition
    }     // End of btn submit method