CSE 142 Homework 1

• assigned Friday, 1 October 1999
• due Monday, 11 October 1999
  • web submission by 3:00 pm
  • paper submission by 5:00 pm

• introduction
• key concepts
• task description
• specifications
• programming guidelines
• submission guidelines (includes link to turn-in page)
• files
• a few bits of advice
• announcements

In this homework, you'll be applying your programming skills to write a program to help a computer store, CompuSell. CompuSell has a discount pricing scheme that is a little too complicated for their sales staff to estimate order prices quickly for prospective customers. CompuSell has contracted you to write a program to assist their sales staff by automating discount pricing computations.

In this section, for most homeworks, we'll provide a list some of the relevant concepts. Don't forget, however, that CS is a lot like math in that you can never afford to forget concepts you learned earlier in the course; every new homework and programming concept builds on previously learned ones. In addition, later in the quarter, determining which concepts you should apply might well be part of your homework.

In this homework, keep an eye out for...

• the programming process: studying the problem, planning a solution, writing code
• input/output (I/O with printf and scanf)
• variables and assignments
• constants (using #define)
• expressions with arithmetic operators (e.g. + - * / %)
• conditionals (using the if statement)

Your program will be used by CompuSell sales representatives to quickly compute price estimates for prospective customer's orders and determine whether the order price is within the customer's budget.

CompuSell's pricing scheme

CompuSell's pricing scheme favors customers who buy many computers:

• Single computers cost $1399.99 each.
• If you buy 6 computers at a time, each 6 computer "Super Sixpack" of computers is given a discount of some amount. The discount is determined on a customer-by-customer basis.

example price computation

For instance, if the customer wants 15 computers, the order consists of 2 Super Sixpacks plus 3 more computers. For a customer whose Super Sixpack discount is $350, each Super Sixpack costs $8399.94 minus $350, yielding a per-Sixpack cost of $8049.94. The total price would be twice this plus three times $1399.99: $20299.85.

Your program should start by reading the Super Sixpack discount for the current customer. This and all other monetary figures should be read and stored as floating-point numbers (type double).

Next, the program should compute and display the cost of a Super Sixpack of computers and the discount which was just read for this customer.

Your program should then read the number of computers the customer wishes to buy. (It should be clear that only an integer value makes sense here.)

Next, it should read the customer's budget, i.e. how much money the customer has available to spend on this order.

Finally, the program should then compute and display the following:

• the number of Super Sixpacks and, if applicable, additional single computers which will add up to the customer's requested quantity
• the total price of the order
• the average price per computer
• some text indicating whether or not the total price is within the customer's budget
  • if so, how much of the budget would remain after the purchase
  • if not, the amount by which the purchase price exceeds the customer's budget

Your program should run just like the sample executable provided below. The computed numbers should be exactly the same. Just as important, the order of the inputs should be exactly the same, i.e. in this case, (1) discount first, (2) number of computers, (3) budget. The wording in the text doesn't have to be identical, but the order of the inputs and outputs and your computed numbers must match exactly.

Use #define macros for the following constant values:

• SINGLE_PRICE, the price of a single computer (before quantity discount) as specified in the task description.
• PACKAGE_COUNT, the number of computers per discount package---in this case, 6.

Be sure to read the homework submission guidelines, linked on the course home page in the Announcements section. As usual, you will have to submit your work (1) via the web using the page linked below and (2) on paper.

The due date for this assignment is at the top of this page. See the homework submission guidelines page for the exact times for the deadlines. Be especially respectful of the web submission deadline, as submission times are tracked extremely precisely by computer. We cannot accept late submissions.

• web turn-in page

• self-extracting archive, including starter C file
  • hw1_vc6.exe - for use with MSVC 6.0
  • hw1_vc5.exe - for use with MSVC 5.0
• hw1_orig.c - starter C file alone

• hw1.exe - sample executable

• Start early. Despite the fact that it improves your life immensely, so many people ignore this advice. It always pays to get an early start.
• Read these instructions completely and carefully.
• Try running the sample executable with various input values.
• Before writing a single line of code, plan your solution on paper. Try thinking about what you would do to perform the computations yourself.
• Before turning in your work, test it thoroughly, comparing results with the sample executable.
• When it comes to grading, there's nothing better than a happy TA. Make your TA a happy TA: Your code should be neat and readable, with sensible variable names.
• We know you haven't seen #define and conditionals yet. We should get through them by the end of Wednesday's lecture, but in the meanwhile, try leaving out the last part of the output (about whether the total price is within budget).
• Start right now!

If any clarifications or changes need to be made for this homework, they will be posted to the cse142-announce email list and linked here.