CMSC104, Fall 2006
Programming Project 2
Book Ordering Software

Out: Friday, October 27, 2006
Due: Friday, November 10, 2006 before 11:59 p.m.

The Objective

This project is designed to give you practice writing a C program on your own. It will also give you practice using a while loop with a sentinel value and Unix redirection.

The Task

Your job is to write a program that will read in the prices of several books purchased from an online bookstore. You will then display the receipt, listing the subtotal, the tax, the cost of shipping and the total cost of the order. You should also print out some statistical information regarding the book order. You should include the total number of books purchased, the average book price, the minimum book price and the maximum book price.

More Details

Your program should use a while loop to read in values one at a time until it reaches the sentinel value of -1. After reading in all of the values, you should do any calculations you need to perform before printing the results to the screen. Keep in mind what we discussed in class about the possibility of the user quitting as soon as he/she runs the program.
The bookstore is offering a shipping promotion. If the price of the order (before tax is added) is $25.00 or greater, the shipping is free. If the order is less than $25.00, shipping is a flat rate of $7.00. You should use the following #defines in your program to represent these values:
```
#define SHIP_COST 7.00
#define FREE_SHIP_LIMIT 25.00
	
```
You should use a tax rate of 5.0 percent. You should consider using a #define for the tax percentage. I'll leave it up to you to decide what it should be.
You should print any monetary values to two decimal places.

Input to the Program

A data file containing the items for you to use as input to your program will be provided. The items are all greater than 0. The last value in the file will be -1. This is the sentinel value that signals the program to stop reading items.

To use the data file as input to your program, you will use Unix redirection. By using redirection, you can get input from a file rather than from the keyboard. The scanf statement that you use in your program will look exactly the same as it would if you were getting your input from the keyboard. Since you will be getting the values from a file instead of from a user typing at the keyboard, you will not need to prompt the user. For instance, if the data file was called books1.dat, you would run your program, using the following command:

       a.out < books1.dat

This is how Unix redirection is done. It is saying to run your executable file using the file books1.dat as input.

I have provided two data files for this project. The first, books1.dat, is an order that qualifies for free shipping. The second, books2.dat, is an order that does not qualify for free shipping. You will need to copy the files into your directory. To do this, go to the directory where you would like to store the data files. Then, use the following command to copy them into the directory:


    cp /afs/umbc.edu/users/d/b/dblock/pub/CS104/Proj2/books*.dat .

Notice that the space and period at the end of the command are part of the command.

Here is a example of what the input data file could look like:

Sample Output


linux2[130]% cat books1.dat
12.95
16.00
24.95
9.95
13.95
59.93
-1
linux2[131]% gcc proj2.c
linux2[132]% a.out < books1.dat

Welcome to  Booksellers!!
	
Your receipt:
	
Subtotal:    $ 137.73
Tax:         $   6.89
Shipping:       FREE!
Final total: $ 144.62
	
Some statistics regarding your order:
	
The total number of books ordered: 6
The average book price: $ 22.96
The minium book price:  $  9.95
The maximum book price: $ 59.93

Thank you for placing your book order!

linux2[133]% cat books2.dat
12.95
9.95
-1

linux2[134]% a.out < books2.dat

Welcome to  Booksellers!!

Your receipt:

Subtotal:    $  22.90
Tax:         $   1.14
Shipping:    $   7.00
Final total: $  31.05

Some statistics regarding your order:

The total number of books ordered: 2
The average book price: $ 11.45
The minium book price:  $  9.95
The maximum book price: $ 12.95

Thank you for placing your book order!

linux2[135]%

Submitting the Program

Your program should be in a file called proj2.c.

Here is a sample submission command. Note that the project name starts with uppercase 'P'.

submit cs104_0101/0501 Proj2 proj2.c

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 cs104_0101/0501 Proj2