void MethodCallTwoOperand(string operation, TextBox res)
{
switch (operation)
{
case "plus":
res.Text = calculator.Plus(Convert.ToDouble(textBox_first_arg.Text),
Convert.ToDouble(textBox_lastarg_or_answer.Text)).ToString(); break;
case "difference":
res.Text = calculator.Difference(Convert.ToDouble(textBox_first_arg.Text),
Convert.ToDouble(textBox_lastarg_or_answer.Text)).ToString(); break;
case "multiply":
res.Text = calculator.Multiply(Convert.ToDouble(textBox_first_arg.Text),
Convert.ToDouble(textBox_lastarg_or_answer.Text)).ToString(); break;
case "divizion":
res.Text = calculator.Divizion(Convert.ToDouble(textBox_first_arg.Text),
Convert.ToDouble(textBox_lastarg_or_answer.Text)).ToString(); break;
case "exponentiation": res.Text = calculator.Exponentiation(Convert.ToDouble(textBox_first_arg.Text),
Convert.ToDouble(textBox_lastarg_or_answer.Text)).ToString(); break;
default:
break;
}
}