private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                //Declare a variable.
                int roman = NumberConversion.ConvertFromRomanToArabic(string.Format(inputTextBox.Text));

                //Display the result to the output label.
                resultOutputLabel.Text = roman.ToString();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void convertButton_Click(object sender, EventArgs e)
        {
            try
            {
                //Declare a variable.
                string arabic = NumberConversion.ConvertFromArabicToRoman(int.Parse(inputTextBox.Text));

                //Display the result into the outputLabel
                resultOutputLabel.Text = arabic.ToString();
            }
            catch (Exception ex)
            {
                //Display the default message
                MessageBox.Show(ex.Message);
            }
        }