The Objective

The objective of this assignment is to give you experience working with pointers and arrays of structures. You'll be doing file handling, dynamically allocating an array of structures, and using passing by reference. Good program design and implementation techniques are expected, as well as separate compilation.

The Background

The CSEE Book Store offers students a selection of Computer Science textbooks that are required or recommended for many of the CMSC courses. 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 and getting the name of the inventory file from the user, presents the user with a list of the book titles found in that file and the specific CMSC courses they are required or recommended for. The books are listed in order of their inventory numbers.

The user can then choose to see more information about one of the books by entering its inventory number or may choose to quit. If the user chooses to see more information about a book, in addition to the title, s/he is shown the isbn number, 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, which is not 0, 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, so that further selections can be ordered.

When the user has finished ordering books, the invoice is completed by showing the subtotal, adding the sales tax (5% of the subtotal) and writing the tax and total. A new inventory file is then produced which is to be formatted exactly like the original inventory file, but with the number of copies adjusted to reflect the books bought on 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 a positive integer.
• Any inventory file we use will have the same format as the one provided, inventory.dat
• The filename of the inventory file will not exceed 49 characters.
• 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 *numBooksPtr);
  where numBooks is an integer declared in main() and whose address is passed to this function so that this function can modify it to hold the number of records in the file. You should prompt the user for the name of the inventory file and open it within this function, handling any errors encountered when attempting to open the file. You should read the first item from the file, the number of records, and modify numBooks. You must return the pointer to the file you opened so that the rest of of the file's contents can be read later in the program. 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.
    In this case we want all of the data to be on one line even if that makes the line exceed 80 characters. Data files are meant for computer use, not for user viewing.
    Each record is made up of the following data in this order:
    • inventory number (positive integer)
    • class number (positive integer)
    • whether required or recommended (an integer used as a boolean,
      where 1 is for required and 0 is for recommended)
    • isbn number (a string of not more than 17 characters)
    • title (a string of not more than 44 characters)
    • author (a string of not more than 33 characters)
    • publisher (a string of not more than 15 characters)
    • the unit price of the book (a float expressed to 2 decimal places)
    • the number of copies in stock (a 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/b/o/bogar/pub directory.
  • REQUIRED and RECOMMENDED should be #define d to be 1 and 0, respectively.
• 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, numBooks, from the file.
• 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). The invoice should not exceed a width of 80 characters. If the user doesn't purchase any books, you shouldn't create an invoice, and so there would be no file called invoice.txt in your directory. (See sample run)
• If a user decides to buy all of the remaining copies of a book, do not remove the book from the inventory list, just show 0 copies in the new inventory file.
• After the user has completed ordering and the invoice.txt file has possibly been produced, you must generate a new inventory file called newInventory.dat This file must be generated, even if no books were ordered, and it should be formatted exactly like the original inventory.dat file.
• You must wait to open a file until you need to read from or write to it and you must close a file as soon as you are finished reading from it or writing to it.
• On normal (non-error) execution of the program, you must free() all memory that you allocated dynamically when you are finished using it.

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