class Prices
        {
            public const double blackink = 0.45;
            public const double redink = 0.50;
            public const double bluewb = 1.20;
            public const double blackwb = 1.10;
            public const double a4 = 2.50;

        }
        protected void btnPurchase_Click(object sender, EventArgs e)
        {
            // Variables
            double blackink, redink, bluewb, blackwb, a4, total1, total2, total3, total4, total5, overallTotal;

            string name, address1, address2, postCode;

            // Assigning Variables
            name = txtName.Text;

            address1 = txtAddress1.Text;

            address2 = txtAddress2.Text;

            postCode = txtpostCode.Text;

            // Conversion
            blackink = Convert.ToDouble(txtBlackInk.Text);

            redink = Convert.ToDouble(txtRedInk.Text);

            bluewb = Convert.ToDouble(txtBlueWB.Text);

            blackwb = Convert.ToDouble(txtBlackWB.Text);

            a4 = Convert.ToDouble(txtA4.Text);

            // If Statement - Black Ink pen
            if (blackink == 0)
            {
                total1 = 0;
            }
            else
            {
                total1 = blackink * Prices.blackink;
            }//end

            // If Statement - Red Ink pen
            if (redink == 0)
            {
                total2 = 0;
            }
            else
            {
                total2 = redink * Prices.redink;
            }//end

            // If Statement - Blue Whiteboard marker
            if (bluewb == 0)
            {
                total3 = 0;
            }
            else
            {
                total3 = bluewb * Prices.bluewb;
            }//end

            // If Statement - Black Whiteboard marker
            if (blackwb == 0)
            {
                total4 = 0;
            }
            else
            {
                total4 = blackwb * Prices.blackwb;
            }//end

            // If Statement - A4
            if (a4 == 0)
            {
                total5 = 0;
            }
            else
            {
                total5 = a4 * Prices.a4;
            }//end

            overallTotal = total1 + total2 + total3 + total4 + total5;

            if (overallTotal > 50.00)
            {
                lblPrice.Text = "You recieved a 5% discount, your overall total is £" + overallTotal * 0.95;
            }
            else
            {
                lblPrice.Text = "Your overall total is £" + overallTotal;
            };



            lblCusName.Text = "Thank you, " + name;
            lblDelivery.Text = "Your stationery items will be sent to " + address1 + ", " + address2 + ". " + postCode;
        }