CPSC-102: Computing and Algorithms II

Programming Assignment 4

Summer 1998

In this programming assignment, you will demonstrate your knowledge of dynamic data structures (in particular, binary search trees) by revising the video database program from Programming Assignment 3 to incorporate a new dynamic data structure.

New Internal Requirements

For this assignment, you should replace your Database class with another implementation which uses binary search trees to organize the lists of videos. As before, you should maintain the database as two separate trees of videos: one for videos currently in stock, and one for videos which have been checked out. The search order for the binary search trees is the same as before: ascending order by title.

New Functional Requirements

Your program will be an extension of Programming Assignment 3, and thus should operate in the same manner as that assignment, unless otherwise specified herein. In particular, this means that any errors present in your submissions for Programming Assignment 3 should be fixed for this assignment.

The following new requirements should be implemented as well:

A new option should be added to the main menu which allows the user to write the contents of the database (including both types of videos) to a file. If selected, the program should prompt the user for the name of a file in the current directory to be used for writing the desired information. The program should then write all videos to that file, in the same format used for input. That is, it should be possible to use the output of this command as input to the program at some future time.
The program should use a pre-order traversal to write the videos from both trees to the file. In this way, if the tree was "well-balanced" at the beginning, it will remain so.
A new option should be added to the main menu which allows the user to re-initialize the database from a file. If selected, the program should prompt the user for a file name. If the file does not exist, an error message should be issued and the program should leave the current database unmodified. If the file does exist, the program should delete the current (internal) database and create a new database based upon the file, as if the program had been originally started with that file as its command-line argument.
New options should be added to the main menu which allow the user to insert and delete videos from the database from the console. If selected, the program should prompt the user for the appropriate information.

Submitting Your Program

Before 11:59:59 p.m., Thursday, 3 September 1998 (9th Thursday), you must email a single file to jhuggins@kettering.edu containing all source code files for your program, including a file named Prog4.java containing a main method.

In addition, you must deliver to the instructor a printout of your program files at the start of class on Friday, 4 September 1998 (9th Friday).

Notes

In order to write to a file, the java.io.FileWriter and java.io.BufferedWriter classes may be used in much the same way that FileReader and BufferedReader are used. There are two significant differences:
- There is no equivalent method to readLine(); you should use a combination of write() (which can write a string to the file) and newLine() (which writes an end-of-line character to the file).
- Once you are finished writing to a file, use the close() method to flush the output buffer to the disk. (Otherwise, data may be lost.)
See the Java API for details.

Jim Huggins / jhuggins@kettering.edu
last updated: 20 August 1998