private void btnSave_Click(object sender, EventArgs e)
        {
            DialogResult result = this.saveFileDialog1.ShowDialog();

            if (result == DialogResult.OK && this.saveFileDialog1.FileName != "")
            {
                AmortizationIO.Write(this.saveFileDialog1.FileName, GetInputData());
            }
        }
        private void btnOpen_Click(object sender, EventArgs e)
        {
            DialogResult result = this.openFileDialog1.ShowDialog();

            if (result == DialogResult.OK && this.openFileDialog1.FileName != "")
            {
                InputDataAmortization input = AmortizationIO.Read(this.openFileDialog1.FileName);
                SetInputData(input);
                UpdateData(input);
            }
        }