equals

        private void btnEquals_Click(object sender, EventArgs e)
        {
            secondInput = double.Parse(lblDisplay.Text);
            switch (operatorSymbol)
            {
                case "+":
                    result = firstInput + secondInput;
                    operatorSymbol = "";
                    break;
                case "-":
                    result = firstInput - secondInput;
                    operatorSymbol = "";
                    break;
                case "*":
                    result = firstInput * secondInput;
                    operatorSymbol = "";
                    break;
                case "/":
                    result = firstInput / secondInput;
                    operatorSymbol = "";
                    break;
            }
            lblDisplay.Text = result.ToString();
        }