public static double CalculateTotal(IEnumerable <OrderItem> orderItems)
{
double totalPrice = 0.0;
foreach (var item in orderItems)
{
IDiscountCalculator discountCalculator
= DiscountFactory.CreateDiscountCalculator(item.DiscountType);
double itemPrice = discountCalculator.GetDiscountedPrice(item);
totalPrice += itemPrice;
}
return(totalPrice);
}