Write a C++ program which maintains an inventory of items using a linked list.
Each item must contain 3 fields: StockNbr, QtyInStock, and ReOrderLevel.


The program must be able to execute single-letter commands, with arguments where necessary.
Commands to execute are:

	H		(help)		Provides a summary of available commands
	R <filename>	(read)		Read the inventory from the specified file
	W <filename>	(write)		Write the inventory to the specified file
	L		(list)		List the entire inventory in alphabetical order
	I <StockNbr>	(inquire)	Display the inventory information for the specified item
	N <StockNbr>	(new)		Adds the specified item to the inventory.  Prompt for ReOrderLevel.
	D <StockNbr>	(delete)	Deletes the specified item from the inventory.
	B <StockNbr>	(buy)		Adds to the quantity in stock for the specified item.  Prompt for quantity.
	S <StockNbr>	(sell)		Subtract from the quantity in stock for the specified item.  Prompt for quantity.
	Q		(quit)		Exits the program.

Provide appropriate error-handling for each command.

Execute the "Write" command and print the text file after executing each of the following commands: "New", "Delete", "Buy", and "Sell".

Print the screen after executing each of the following commands:  "Help", "List", and "Inquire".

Submit a print-out of the code and the printouts for the 7 commands.