CS210: Intermediate Computing/Data Structures (Java)
This lab gives you
experience developing a class that implements a queue using a circular
array. In this lab, you will ignore the
possibility of needing to expand capacity.
The test case code provided does not test your code for its behavior in
Prior to the lab session, do
the following to get started:
save, and unzip the file Lab5.zip on your removable
media (floppy disk, Zip disk, or memory stick) creating a directory named Lab5.
the Dr Java Application on your PC.
a new Dr Java project in the Lab4 directory by selecting the menu Project
-> New… naming the project file Lab5 and saving it in your new Lab5
directory. (Dr Java automatically opens
file in the editor window which you will ignore.)
the menu File-> Open, open the files: CircularArrayQueue.java,
EmptyCollectionException.java, QueueADT.java, and QueueTest.java. Dr Java will automatically include this
source file in the Project. Use the menu
-> Save to save the updated project file.
Study the code for the
CircularArrayQueue class so that you understand what it needs to do. This code is not complete.
need to design and add code to the methods of the CircularArrayQueue class in
places as indicated by the comments:
1. In the constructor(int initialCapacity), you need to
instantiate the array and initialize the attributes: front, rear, and count.
2. In the enqueue method, you need to add an element to
the array in the correct place based on the state of the circular array.
3. In the dequeue method, you need to return an alias of
the reference to the first element in the queue and remove it.
4. In the first method, you need to return an alias of
the reference to the first element in the queue.
Using the menu Project -> Compile Project,
compile the program. Test your code by
selecting the TestQueue.java file and using the DrJava Tools -> Test Current
Document menu. This will run
four different JUnitTestCases on your implementation of the CircularArrayQueue
class. This will verify that your
CircularArrayQueue object with the correct initial state.
method calls and leaves the object in the correct state.
dequeue method calls and leaves the object in the correct state.
wraparound of the contents of the queue in the array correctly.
Show your code to the TA
before leaving the lab. When you are
through with the lab, close the Project using the menu Project -> Close. Be sure to remove your media and take it with
you. If you have not finished the code,
finish it by the next lab period. You
will need to add to this code in the next lab to handle expand capacity.
Before you leave, have your TA check your
code in progress. If you have not
completed it, finish it before the next lab session to include a hard copy with
your lab report.
Write a document that
answers the following questions. Your lab must be printed (not
Answer the following
questions related to implementing a circular queue in an array.
1. What is the benefit of using a circular queue
relative to implementing a regular queue in an array?
2. How and where do you use the modulo operator in the
Note: You should work alone on the lab report.
assignment is due at the BEGINNING of your next lab. No late assignments
will be accepted. Emailed assignments will not be accepted. If you
are not going to be in lab on the due date, you can turn the assignment ahead
of time to the CS210 TA box in the CS department office.