private void btnAdd_Click(object sender, EventArgs e)
        {
            string name  = tbName.Text;
            float  grade = 0;

            try
            {
                grade = float.Parse(tbGrade.Text);
            }catch (Exception)
            {
                MessageBox.Show("form contains errors");
            }
            string cnp = tbCnp.Text;

            string option = comboBox1.Text;

            Candidate candidate = new Candidate(name, grade, cnp);

            if (option == "Licence")
            {
                licence += candidate;
            }
            else if (option == "Master")
            {
                master += candidate;
            }
            else
            {
                MessageBox.Show("Select a type!");
            }
        }
 public Form1()
 {
     InitializeComponent();
     licence = new Licence();
     master  = new Master();
 }
 public ViewForm(Licence licence, Master master)
 {
     this.licence = licence;
     this.master  = master;
     InitializeComponent();
 }