Stuff

 //If-else for discountPercent
            if (discountPercent == 0) {
                if (total < 20)
                    discountPercent = total * 0.05;
                else if (total >= 25)
                    discountPercent = total * 0.10;
                else if (total < 75)
                    discountPercent = total * 0.10;
                else if (total >= 75)
                    discountPercent = total * 0.15;
                else if (total < 100)
                    discountPercent = total * 0.15;
                else if (total >= 120)
                    discountPercent = total * 0.20;
            }