public void FeedMoney(decimal dollars)
        {
            VendingFileWriter vfw = new VendingFileWriter();

            vfw.WriteToLog("FEED MONEY:   $" + balance + "  $" + (balance + dollars));
            this.balance += dollars;
        }
        public VendableItem Purchase(string slot)
        {
            if (!IsSoldOut(slot))
            {
                if (items[slot][0].Price <= this.balance)
                {
                    VendableItem      selection = items[slot][0];
                    VendingFileWriter vfw       = new VendingFileWriter();
                    vfw.WriteToLog($"{items[slot][0].Name}  {slot}   $" + balance + "  $" + (balance - items[slot][0].Price));
                    balance -= items[slot][0].Price;
                    purchasedItems.Add(items[slot][0]);
                    items[slot].Remove(items[slot][0]);

                    return(selection);
                }
                else
                {
                    Console.WriteLine("Insufficient funds. Please insert more money!");
                    return(null);   // return nothing because not enough money!
                }
            }
            else
            {
                Console.WriteLine("Item is sold out. Please select something else.");
                return(null);    //return nothing because it is sold out
            }
        }
        public void CompleteTransaction() //placeholder
        {
            ChangeMaker c = new ChangeMaker(this.balance);

            c.MakeChange();
            VendingFileWriter vfw = new VendingFileWriter();

            vfw.WriteToLog("Give Change:   " + balance + "  " + ("$0.00"));
            this.balance = 0;
            foreach (VendableItem e in purchasedItems)
            {
                Console.WriteLine(e.Consume());
            }
            purchasedItems.Clear();
        }