public void UnaryOperatorCLick(object sender, TextView textView, EventArgs e , IUnaryOperator unary_operator_passed, string operator_display)
{
History_list.Add (operator_display);
History_list.Add (textView.Text);
History_list.Add("\r\n");
string pendingUnaryOperator = sender.ToString();
UopClicked = true;
UnaryResult = unary_operator_passed.perform(Convert.ToDouble(textView.Text));
textView.Text = Convert.ToString(UnaryResult);
}
