The Objective

The objective of this assignment is to give you experience working with pointers. You'll be doing file handling, dynamic memory allocation, and passing by reference. You will also continue to practice using good program design and implementation techniques.

The Background

The CSEE Book Store offers students a selection of Computer Science textbooks that are required for many of the CS core courses as well as a few reference books. The store keeps track of the books in inventory with an inventory file. A student can use the order system to purchase single or multiple copies of the books available. The system creates an invoice for the student and also removes the books ordered from the inventory.

The Task

Design and code a project that after printing a greeting to the user, presents the user with a list of the book titles available. The user can then choose to see more information about one of the books on the list or quit. If the user chooses to see the information about a book, s/he is presented with the book's ISBN number, title, author, publisher, the price per copy and the number of copies in stock. The user will then enter the number of copies s/he wants to order (0 is a possibility).

Once the user has entered the number of copies to order, a line item is generated and written on the invoice and the inventory is decreased by that number of copies. The user is then presented with the list of titles again.

When the user has finished ordering books, the invoice is completed by adding the sales tax (5% of the subtotal) and writing the tax and total. A new inventory file is then produced which is exactly like the original inventory file but with the new numbers of copies adjusted to reflect the order.

Sample Run

Although your output need not be identical to the above, all information (including the greeting) must be present.

Please be aware that this is definitely NOT a complete test of the program. Your testing should be much more extensive.

Input Guarantees

• The first item in the inventory file is the number of records in the file. It is an integer.
• Any inventory file we use will have the same format as the one provided, inventory.dat
• Graders will enter only integers as book choices

Further Specifications

• You must use separate compilation for this project. You may have as many .c and .h files as you want to fit your project design. Your file that contains main() should be called proj3.c You must have at least 3 files.
• You MUST have a function called OpenInventoryFile which has the following function prototype:
  FILE* OpenInventoryFile (int *numPtr);
  where num is the number of records in the file.
  You may not change this prototype in any way.
• The inventory.dat file has the following information:
  
  • The first item in the file is the integer number of records in the file.
  • After that, each record is on one line and is made up of the following data in this order:
    
    • inventory number (positive integer)
    • ISBN number (a string of not more than 14 characters)
    • title (a string of not more than 49 characters)
    • author (a string of not more than 34 characters)
    • publisher (a string of not more than 19 characters)
    • the unit price of the book (float expressed to 2 decimal places)
    • the number of copies in stock (non-negative integer)
  • You may get a copy of the inventory.dat file from my account. The file is in the /afs/umbc.edu/users/s/b/sbogar1/pub directory.
• You MUST use dynamic memory allocation (malloc or calloc) to allocate the memory to hold the array of structures after you have read the number of records from the file (num). HINT: num is modified by the function OpenInventoryFile() since it is passed by reference into that function.
• The filename "inventory.dat" should be hard-coded in the function OpenInventoryFile().
• If any file fails to open, you should print an appropriate message to the screen and exit the program.
• The invoice is to be written to a file called invoice.txt (not to the screen).
• After the user has completed ordering and the invoice.txt file has been produced, you must generate a new inventory file called newInventory.dat
• You must close all files as soon as you are finished either reading from them or writing to them.
• On normal (non-error) execution of the program, you must free all memory that you allocated dynamically.

Submitting the Program

Here is a sample submission command. Since you may have different file names you'll have to adjust it to fit your needs. As always, be sure to submit all of the files necessary for your project to compile.
Note that the project name starts with uppercase 'P'.

submit cs201 Proj3 proj3.c bookstore.c bookstore.h

To verify that your project was submitted, you can execute the following command at the Unix prompt. It will show the file that you submitted in a format similar to the Unix 'ls' command.

submitls cs201 Proj3