private void parseBtn_Click(object sender, EventArgs e)
        {
            //this creates a variable that will hold the equation as a string
            string equation;
            try
            {

                equation = equationTxt.Text;
                if (equation != "")
                {

                }
                else
                {
                    MessageBox.Show("Please enter a valid equation");
                }

            }
            catch
            {
                MessageBox.Show("Please enter a valid equation");
            }

        }