(Latest Revision: 09/02/2000)

The Strange Stack: Implementing a Data Structure

RATIONALE:

One of the main points of this exercise is to impress upon you that abstract data structures need not be implemented in a way that conforms at all to preconceived notions. Often programmers need to find new and creative ways to implement the data structures they want to use.

THE ASSIGNMENT:

Implement a stack of letters in an unusual way: using just a single unsigned long int to contain the stack elements. In other words one integer variable will be used as a stack that can store several letters.

WHAT I GIVE YOU:

I am giving you a main program called driver.cpp, a header file called stack.h, and a form for a stack.cpp file called stack.cpp.form. Make copies of those files and look them over carefully. By reading stack.h, you will learn the specifications for the stack operations that I want you to implement. The file driver.cpp is just that: a driver program you can use to test your implementation of the stack.

WHAT YOU GIVE ME:

After you understand stack.h, make a copy of stack.cpp.form and name it stack.cpp. Fill it in with your name, user name, and implementations of all the functions in stack.h. Look at pages 263-264 in your textbook for an idea of the format you need to use. Keep in mind, however, that the source code you must create will be radically different from the code you see in the book.

Create a comprehensive test plan for making sure that all the functions you have implemented work according to specifications. E-mail me a copy of the completed stack.cpp file plus a script showing that you used the driver to run all your tests successfully. You may look at my directions on how to make a script. You may also check out these sample scripts: top-level run, level-two run, and level-three run.

ADDITIONAL SPECIFICATIONS:

Before you do any assignment for me, you need to read the programming assignment rules. This document contains my general rules regarding form, and style. The document also describes my grading criteria. (Note: on this assignment you are not required to write any function header comments -- I have provided you with all of them.)

Together, the files stack.h and stack.cpp must implement a stack class. You are not allowed to change anything in stack.h or in driver.cpp. In fact when I test your version of the stack.cpp file, I will just compile it together with my (original) copies of driver.cpp and stack.h. Therefore, you must write stack.cpp so it works correctly in conjunction with the original stack.h and driver.cpp. You must implement the stack operations exactly as they are specified in the header comments in stack.h.

The stack class must use the private variable "data" defined in stack.h for storage of all stack elements. The variable "data" is a single unsigned long int. The element set for the stack class must be the set of lower case letters, 'a' through 'z.' When your program is compiled on the Sun Ultra's using the g++ compiler, a member of your stack class must have a capacity of at least six lower case letters. You can achieve this easily if you take advantage of the fact that you only need 26 different "codes" for stack elements.

HELP:

Figuring out the details of this implementation can be tricky. Come to class to get helpful information.
WHAT TO TURN IN:

You will be sending me two e-mail messages. Please follow these rules: Send the following two items to me by e-mail before midnight on the due date: Note that there are no spaces in the subject lines given. It is important that you do not insert any spaces. My e-mail address is: john@ishi.csustan.edu.

DUE DATES:

For due dates, see the class schedule.