computer science homework

CPS 350: Assignment 1 Due 11:55 pm, 2/1/2017 (100 pts)

No late submission will be accepted

Receive 5 bonus points if turn in the complete work without errors at least one day before deadline

Receive an F for this course if any academic dishonesty occurs

1. Purpose The purpose of this assignment is to implement a Stack ADT in the two most common ways,

an array and a linked list. You will implement stacks for Java double numbers.

2. Description Your Stack implementations will be used to do sound manipulation, namely reversing a sound

clip. This process, called "backmasking," was used by musicians including the Beatles, Jimi

Hendrix, and Ozzy Ozbourne. You will write a program that reads a sound file in the .dat format

and writes another .dat sound file which is the reverse of the first. The sample code has provided

a class Reverse whose main method reads in a .dat sound file, pushes all the sound values on a

stack, then pops them all off and writes them into a new .dat sound file. The sample code has also

provided an interface DStack, which defines a stack that holds double values. Your first job is

to familiarize yourself with these files.

2.1. Implementing the Stack ADT (70 points)

You need to provide two stack implementations, one using an array and one using a linked

list. They should be called ArrayStack and ListStack, respectively. They should implement

the DStack interface given to you. Reverse should work and create backward sound files once

you complete these two implementations. Your array implementation should start with a small

array (say, 10 elements) and resize to use an array twice as large whenever the array becomes full,

copying over the elements in the smaller array. While there are convenient Java library methods

for copying arrays, for this assignment, use your own loop to copy array elements manually (so

you can "see" the work involved in copying).

Both ArrayStack and ListStack should throw an EmptyStackException if pop() or peek() is

called when the stack is empty. To use EmptyStackException, add the following line to your file:

import java.util.EmptyStackException;

The only Java class that you should use to complete the implementations of your stacks

is java.util.EmptyStackException. You should also use the length field of an array.

2.2. Running Reverse (10 points)

The Reverse program takes 3 arguments (also known as "command-line arguments"). The

first is the word array or list and specifies which implementation to use. The next two are the

input and output .dat file names (you need to include the .dat extension). Running the program

will depend on your system; from a command line it will look something like:

java Reverse list in.dat out.dat

In an IDE there is usually a dialog box for setting program parameters which contains a field

for the program arguments. (For example, in Netbeans select Build->Run Arguments and a bar

will appear at the top of the screen that allows you to type in the arguments. Read more about

setting command line parameters in Netbeans.)

To test your program, create short .dat files by hand to aid testing.

Note that Reverse.java just uses your stacks in one particular way: pushing a bunch of

elements onto the stack and then popping them all off.

2.3. The .dat File Format

The .dat file format starts with one line describing the sample rate of the sound file. This

line is required. The rest of the file is composed of two columns of numbers. The first column

consists of the time (measured in seconds) when the sample was recorded, and the second

column contains the value of the sample, between -1.0 and 1.0. This is the beginning of a sample

.dat file. Notice that the numbers in the first column increase by 1/44100 each step. This is

because the sample rate is 44.1kHz.

; Sample Rate 44100

0 0

2.2675737e-05 0

4.5351474e-05 0

6.8027211e-05 0

9.0702948e-05 0

0.00011337868 0

0.00013605442 0

0.00015873016 0

0.00018140590 0

0.00020408163 0

Note that all you need to do is implement the stacks, as the provided Reverse.java does file

input/output for you. We are explaining the format because it will be helpful for writing short

files by hand for testing purposes.

In order to play sounds you produce, you need a way to convert between the .dat format and

a format that common media players (Windows Media Player, winamp, RealPlayer, etc.)

understand, such as .wav.

sox allows you to convert to and from .dat sound files. The .dat files are useful because

they are human-readable, text-based, sound files. Many versions of sox are available. You can

download the one you need from http://sourceforge.net/projects/sox/files/sox/ by clicking on

the folder for the most recent version (e.g., “Download sox-14.4.2-win32.exe (2.7 MB)”) and

then downloading the correct file for your operating system.

The Windows and Mac version are also a command-line program and work in the same way

as the UNIX version described below. See below for some pointers on using it.

For those of you who are not familiar with command-line operations, here is

how to use the sox program from Windows.

1. download the "sox12181" zip file from SourceForge. Unzip and extract

the sox file to your desktop.

2. In windows: click Start -> All Programs -> Accessories -> Command

Prompt. A command-line window should appear.

3. In the Command Prompt window, type: cd desktop

4. In the Command Prompt window: (with the sound file you wish to convert

on the desktop as well), type

sox secret.wav secret.dat

5. Now you should see the converted file secret.dat on your desktop.

The general strategy for using sox is as follows.

1. Take a .wav sound file of your choosing, e.g., mysong.wav. This sound shouldn't be

longer than a few seconds, or your program will run out of memory.

2. Convert it to a .dat file: sox mysong.wav mysong.dat

3. Manipulate it with the program you will write: java Reverse list mysong.dat mysong-reversed.dat

4. Convert it back to a .wav file: sox mysong-reversed.dat mysong-reversed.wav

5. Listen to it with your favorite sound player.

That's all there is to it! You may send your reversed secret .dat file to your classmate and ask

him/her to reverse it and find the original message ☺

2.4. Questions (20 points)

Submit a report (in word or pdf), answering the questions below.

1. How did you test that your stack implementations were correct?

2. Your array stacks start with a small array and double in size if they become full. For

a .dat file with 1 million lines, how many times would this resizing occur? What about

with 1 billion lines or 1 trillion lines (assuming the computer had enough memory)?

Explain your answer.

3. Include a description of how your project goes "bonus components" the basic

requirements (if it does).

4. What did you enjoy about this assignment? What did you not enjoy? What could you

have done better?

5. What else, if anything, would you would like to include related to this homework?

2.5. Bonus Components (5 points) – Shrink the array when needed

The following suggestion is meant for you to try if you finish the requirements early.

• Modify your array implementations so that when the array is 3/4 empty, the stack resizes

to use an array of half the size.

2.6. Java Help

For this assignment you need to implement an interface, DStack, in two ways. The

DStack interface defines a simple stack:

public interface DStack {

public boolean isEmpty();

public void push(double d);

public double pop();

public double peek();

}

An actual interface includes comments, including a description of how pop() and peek() should

behave if they are called when the stack is empty. To implement this interface, write a class as

follows:

public class ArrayStack implements DStack {

public ArrayStack() {

// Your constructor code

}

public boolean isEmpty() {

// Your isEmpty() code

}

public void push(double d) {

// Your push() code

}

// continue with the rest of the methods,

// along with any fields, etc.

}

The ListStack class should be defined similarly. You should include appropriate comments

as needed. In particular, each file should begin with a comment that describes the class in the

file, and includes your name and other identifying information.

3. Grading notes If your program does not compile, you receive zero points for that program. Additional

deductions:

1. (5 points) Your code does not follow the style guide discussed in class/textbook.

2. (30 points) Your code does not have author name, date, purpose of this program,

comments on the variables and methods, etc.

4. Turn in

ZIP the following files. Submit the ZIP to isidore.

• ArrayStack.java

• ListStack.java

• ListStackNode.java, the linked-list node for use with your ListStack class. However,

you are also free to use an inner class inside ListStack in which case you will not have a

separate file.

• Write answers for 2.4) Questions in a word file. Print the word file and submit it in class.