Description
Learning Goals:
• Familiarization and practice with key/value association
data structure usage and hash table concepts
• Familiarization and practice using the STL’s
unordered_map container interface
• Reinforce the similarities and differences between
sequence and associative containers
• Reinforce reading persistent data from disk files and
storing in memory resident data structures
• Reinforce modern C++ object-oriented programming
techniques
Description:
This project analyzes words in English text using a hash table to store words. The main task is to count the
occurrences of each word in a novel – called its word frequency. Text analysis using word frequencies is used
in linguistics.
You are given the public interface of class WordFrequency. Your task is to complete the class
implementation. You are provided with starter code that forms your point of departure to complete this
assignment:
1. main.cpp – This file is provided, requires no modifications, and will be overwritten during the grading
process. Function main() orchestrates the flow of execution and tests your intermediate results along
the way.
2. WordFrequency.hpp/WordFrequency.cpp – The class has a single member attribute of type
std::unordered_map, which is the C++ Standard Library’s implementation of a hash table, to store the
association of words (key) to the number of times that word occurs (value).
a. WordFrequency – This (default) constructor takes a reference to an input stream as a parameter
defaulted to console input (e.g., std::cin). This function is to
i. Read a single word at a time from the input stream until end of file. Words are delimited by
whitespace as defined in standard C++.
ii. For each word read, accumulate the number of times that sanitized word has appeared in the
text as the word’s frequency.
Constraint: Only “sanitized” words shall be added to the hashtable. For example, leading and trailing
punctuation, parentheses, brackets, etc. should be removed, but intra-word punctuation should
remain. A working sanitize function has been provided.
b. numberOfWords – This function takes no arguments and returns the number of unique words.
c. wordCount – This function takes a constant reference to a standard string as a parameter and returns
the frequency of occurrence of that sanitized word, or zero if the word is not found in the hashtable.
d. mostFrequentWord – This function takes no arguments and returns the most frequent word, or the
empty string if the hashtable is empty.
e. maxBucketSize – This function takes no arguments and returns the size of the largest bucket in the
hashtable. See the unordered_map’s bucket interface at
https://en.cppreference.com/w/cpp/container/unordered_map
Rules and Constraints:
1. You are to modify only designated TO-DO sections. The grading process will detect and discard any
changes made outside the designated TO-DO sections, including spacing and formatting. Designated
TO-DO sections are identified with the following comments:
///////////////////////// TO-DO (X) //////////////////////////////
…
/////////////////////// END-TO-DO (X) ////////////////////////////
Keep and do not alter these comments. Insert your code between them. In this assignment, there are
8 such sections of code you are being asked to complete. 2 of them are in WordFrequency.hpp and 6
are in WordFrequency.cpp.
2. This assignment requires you redirect standard input from “The Legend of Sleepy Hollow by Washington
Irving.txt” and redirect standard output to “output.txt”.
Reminders:
• The C++ using directive using namespace std; is never allowed in any header or source file in any
deliverable product. Being new to C++, you may have used this in the past. If you haven’t done so already, it’s
now time to shed this crutch and fully decorate your identifiers.
• A clean compile is an entrance criterion. Deliveries that do meet the entrance criteria cannot be graded.
• Always initialize your class’s attributes, either with member initialization, within the constructor’s initialization
list, or both. Avoid assigning initial values within the body of constructors.
• Use Build.sh on Tuffix to compile and link your program. The grading tools use it, so if you want to know if you
compile error and warning free (a prerequisite to earn credit) than you too should use it.
• Filenames are case sensitive on Linux operating systems, like Tuffix.
• You may redirect standard input from a text file, and you must redirect standard output to a text file named
output.txt. Failure to include output.txt in your delivery indicates you were not able to execute your program
and will be scored accordingly. A screenshot of your terminal window is not acceptable. See How to build and
run your programs. Also see How to use command redirection under Linux if you are unfamiliar with command
line redirection.
Deliverable Artifacts:
Provided files Files to deliver Comments
main.cpp
CheckResults.hpp
1. main.cpp
2. CheckResults.hpp
You shall not modify these files. The grading process will
overwrite whatever you deliver with the one provided with this
assignment. It is important that you deliver complete solutions,
so don’t omit these files.
WordFrequency.hpp
WordFrequency.cpp
3. WordFrequency.hpp
4. WordFrequency.cpp
Start with the files provided. Make your changes in the
designated TO-DO sections (only). The grading process will
detect and discard all other changes.
5. output.txt
Capture your program’s output to this text file using command
line redirection. See command redirection. Failure to deliver
this file indicates you could not get your program to execute.
Screenshots or terminal window log files are not permitted.
Readme.* Optional. Use it to communicate your thoughts to the grader
• Frankenstein or The
Modern Prometheus by
Mary Shelley.txt
• The Legend of Sleepy
Hollow by Washington
Irving.txt
Text files to be used as program input. Do not modify these
files. They’re big and unchanged, so don’t include it in your
delivery.
Redirect standard input to The Legend of Sleepy Hollow by
Washington Irving.txt
sample_output.txt
Sample output of a working program. Use for reference, your
output format may be different. But the contents should match.
Do not include this file with your delivery.
