static void Main()
{
Store.Instance.AddProductToStore("A", 50);
Store.Instance.AddProductToStore("B", 30);
Store.Instance.AddProductToStore("C", 20);
Store.Instance.AddProductToStore("D", 15);
PromotionFactory.Instance.AddNewPromotionOne("A", 3, 130);
PromotionFactory.Instance.AddNewPromotionOne("B", 2, 45);
PromotionFactory.Instance.AddNewPromotionTwo("C", "D", 30);
Cart cart1 = new Cart();
cart1.AddPurchaseToCart("A", 1);
cart1.AddPurchaseToCart("B", 1);
cart1.AddPurchaseToCart("C", 1);
Billing.Instance.Bill(cart1);
Console.WriteLine("Scenario A");
Console.WriteLine(Billing.Instance.FinalBill);
Console.WriteLine("");
Console.WriteLine("");
Cart cart2 = new Cart();
cart2.AddPurchaseToCart("A", 5);
cart2.AddPurchaseToCart("B", 5);
cart2.AddPurchaseToCart("C", 1);
Billing.Instance.Bill(cart2);
Console.WriteLine("Scenario B");
Console.WriteLine(Billing.Instance.FinalBill);
Console.WriteLine("");
Console.WriteLine("");
Cart cart3 = new Cart();
cart3.AddPurchaseToCart("A", 3);
cart3.AddPurchaseToCart("B", 5);
cart3.AddPurchaseToCart("C", 1);
cart3.AddPurchaseToCart("D", 1);
Billing.Instance.Bill(cart3);
Console.WriteLine("Scenario C");
Console.WriteLine(Billing.Instance.FinalBill);
}