CP4044 – Programming for Systems and Networks
Mel Ralph Page 1 25/10/2007
Assignment 1
Your task is to develop a word frequency counting program in Java.
The program will read text from an input file, and produce a list of the words found in the file
with a count of the number of times each word has been encountered. For the purpose of this
assessment the input files will be plain ASCII text files, not word processor files.
The program will be executed from the command line, with the filename and any other
required data being passed as command-line arguments.
You may only use an array data structure (covered in the module) to implement the program.
In particular, you cannot use Vector or JCF classes.
Basic Solution (Grade D)
The program will produce as output a list of words with counts of the number of times each
word has been encountered in the input document. The list should be in either alphabetical
word order or in order of word frequency. You may assume that words are delimited by
white-space characters (i.e. newline, carriage return, tab or space).
The following are suggestions for improving on the basic solution, with indicative grades:
Grade C
The program does not crash when run with invalid input.
The order of words in the output will be determined by the presence of the command line flag,
-a implying that the words be listed in alphabetical order or the flags –n or -nr implying the
words are listed with the least (-n) or most (-nr) frequent first. Use alphabetical order within
groups of words with equal frequency.
Grade B
Care will be taken to remove punctuation from input text at the start and end of words (i.e.
input such as “the end” will be seen as the two words the and end with the quotes removed),
but punctuation in the middle of a word (e.g. St.John) may be retained. A further command
line flag (-cn) will produce output in n columns equally spaced across the screen.
For extra credit the program will be capable of processing a number of files listed on the
command line. The quality of the command line interface is comparable to DOS and
Unix/Linux utilities.
Grade A
The program will handle files written in HTML. All “mark-up” will be ignored in preparing the
counts. For extra credit the program will be capable of fetching HTML files “off-the-net” and
will be capable of producing the output as an HTML formatted document.
For extra credit attempt to determine how the processing time of you program is related to the
size of the input file. Compare the performance and results of your program with the
Unix/Linux command:
tr –cs ‘[:alnum:]’ ‘[\n*]’ < data-file | sort | uniq –c | sort –nr
CP4044 – Programming for Systems and Networks
Mel Ralph Page 2 25/10/2007
Submitting the Assignment
The deadline for handing this assignment in to Registry is Friday, 23 November (week 9).
You should submit a printed copy of the program documentation with a floppy disk or CD
securely attached containing the program source and executable files.
All programs must be written in standard Java and any non-core classes used should be
documented.
The documentation should include a commented listing of the source code (printed in a non-
proportional font) and the output produced by the program processing various test files. You
should make an attempt to process at least one file of substantial size, although full output for
processing a file is not required. (You can obtain a suitable large test file from Project
Gutenberg, . For example, ‘The Count of Monte Cristo’ is over
2MB).
Include a critical evaluation of the program, commenting on the program performance, i.e.
execution time, accuracy of the parsing, etc. Reference any sources used other than the
lecture and workshop notes.
You may be required to demonstrate your program.
In assessing your program, attention will be paid to the observation of good programming
practice.
