private void create_article_Click(object sender, EventArgs e)
        {
            Exam            newExam   = new Exam();
            ExamInformation examModal = new ExamInformation(newExam);

            if (examModal.ShowDialog() == DialogResult.OK)
            {
                studentInfo.AddExam(newExam);
                //studentInfo.CalculatePagesAndAuthors();
                //articles_list.Items.Add(newArticle.ToString());
                //total_pages_label.Text = studentInfo.TotalPagesNumber.ToString();
            }
            else
            {
                MessageBox.Show("Changes was not saved");
            }
        }
        private void edit_Article_Click(object sender, EventArgs e)
        {
            int selectedIndex = exams_list.SelectedIndex;

            if (selectedIndex < 0 || selectedIndex >= studentInfo.Exams.Count)
            {
                MessageBox.Show("You need to choose exam!");
                return;
            }
            ExamInformation articleModal = new ExamInformation(studentInfo.Exams[selectedIndex]);

            if (articleModal.ShowDialog() == DialogResult.OK)
            {
                exams_list.Items[selectedIndex] = studentInfo.Exams[selectedIndex].ToString();
                // studentInfo.CalculatePagesAndAuthors();
                //total_pages_label.Text = studentInfo.TotalPagesNumber.ToString();
            }
            else
            {
                MessageBox.Show("Changes was not saved");
            }
        }