public void btnEqual_Click(object sender, RoutedEventArgs e)
{
//calculate using parser class, output to mainText and history box
string expression = tbMainText.Text;
try
{
Parser parser = new Parser(expression);
parser.usingDegrees = btnDegRad.Content.Equals("deg");
previousEntry.Add(tbMainText.Text);
previousIndex = 1;
tbMainText.Text = parser.Calculate();
lbHistory.Items.Add(expression + "=" + tbMainText.Text);
lbHistory.ScrollIntoView(lbHistory.Items[lbHistory.Items.Count - 1]);
}
catch (Exception error)
{
tbMainText.Text = "ERR: " + error.Message;
}
firstIn = true;
}