Assignment 2 Practicing your Development and Design Skills

CMPT 145

Principles of Computer Science
Assignment 2
Practicing your Development and Design Skills

General Instructions
• Each question indicates what to hand in. You must give your document the name we prescribe
for each question, usually in the form aNqM, meaning Assignment N, Question M.
• Make sure your name and student number appear at the top of every document you hand in.
These conventions assist the markers in their work. Failure to follow these conventions will result
in needless e?ort by the markers, and a deduction of grades for you.
• Do not submit folders, or zip ?les, even if you think it will help.
• Programs must be written in Python 3.

Version History
• 05/23/2019: released to students

Question 1 (30 points):
Purpose: To practice the development process for a familiar problem that is complex enough to be interesting. You are to follow a development process, as outlined in the readings and lectures. You
are expected to plan the development of this application, starting from the requirements description,
given below.
Degree of Di?culty: Moderate
A Sudoku Square is a 9 × 9 square of numbers with 3 constraints. The ?rst two constraints concern rows
and columns:
• Every row contains all the numbers from 1 to 9 exactly once.
• Every column contains all the numbers from 1 to 9 exactly once.
In addition, the sudoku square has 9 blocks that are 3×3 in size, and there is one constraint on these blocks:
• Every block contains all the numbers from 1 to 9 exactly once.
All three constraints must be true simultaneously.
Below are two 9 × 9 squares, but only one of them is a Sudoku Square.
4 7 5 1 8 9 2 3 6
2 8 3 4 6 5 1 9 7
6 9 1 2 7 3 5 4 8
9 3 2 6 5 8 7 1 4
7 4 6 9 1 2 3 8 5
1 5 8 7 3 4 9 6 2
3 2 7 8 9 6 4 5 1
8 1 9 5 4 7 6 2 3
5 6 4 3 2 1 8 7 9 .
4 6 7 5 8 1 2 3 9
5 1 2 7 9 4 8 1 6
1 8 9 3 2 6 5 7 4
6 1 8 2 3 9 7 4 5
7 2 3 1 4 5 9 6 8
9 4 5 6 7 8 1 2 3
3 5 1 9 6 7 4 8 2
2 9 4 8 1 3 6 5 7
8 7 6 4 5 2 3 9 1
The square on the left is a sudoku square. The one on the right is not, because of an extra “1” in the second
row and second column. The lines in the squares above are drawn to highlight the blocks visually in this
description.
Usually, Sudoku is posed as a puzzle, with blanks for the puzzle solver to ?ll in. We will not be ?lling in
any blanks, or solving any Sudoku problems. We are simply concerned with checking the validity of a
9 × 9 square of integers, according to the de?nitions above.
Requirements
You will develop a software application in Python that does the following:
• Opens and reads a text document containing 9 rows of 9 integers.
• Determines whether or not the 9 rows of 9 integers is a true Sudoku square (see above)
• Reports a simple yes if it is, and no if it is not.
You can ?nd several example ?les on the Moodle page for the assignment; the examples named sudoku_1.txt
etc. will be true sudoku squares, and the ones named pseudoku_1.txt etc. will not be true sudoku squares.
The example ?les will have 9 rows and nine columns of integers. Here’s an example:
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Department of Computer Science
176 Thorvaldson Building
110 Science Place, Saskatoon, SK, S7N 5C9, Canada
Telephine: (306) 966-4886, Facimile: (306) 966-4884
CMPT 145
Summer-Spring 2019
Principles of Computer Science
✞ ☎
UNIX % more sudoku_3 . txt
6 1 9 3 2 8 7 4 5
3 8 7 4 5 6 9 2 1
2 4 5 7 9 1 8 6 3
8 2 1 9 6 4 3 5 7
5 3 6 2 1 7 4 8 9
9 7 4 5 8 3 6 1 2
4 5 2 6 3 9 1 7 8
1 6 3 8 7 2 5 9 4
7 9 8 1 4 5 2 3 6
✝ ✆
Notice that there are no lines in the data; just a 9 rows of 9 integers each.
What to Hand In
• A text document named a2q1_design.txt containing your design plan. Suggestion: your design plan
should include the interface of your functions without implementation and the equivalence class
and/or boundary cases for your test script.
• A Python program named a2q1.py containing your implementation plan.
• A Python script named a2q1_testing.py containing your test script.
Be sure to include your name, NSID, student number, course number and laboratory section at the top of
all documents.
Evaluation
• 10 marks: Your design plan demonstrated careful planning, including functions, testing, and other
important aspects.
– Your design plan document describes a number of functions in terms of inputs, outputs, and
purpose. It describes test cases for each function.
• 10 marks: Your implementation meets the requirements.
– Your application reads the named ?le containing 9 rows with 9 columns of integers.
– Your application determines if a 9 × 9 square is a true sudoku square.
– Your application outputs yes or no only.
• 10 marks: Your test script demonstrates careful testing.
– You have testing for each function in your implementation.
– Your testing is thorough, and could identify errors in your implementation.
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Department of Computer Science
176 Thorvaldson Building
110 Science Place, Saskatoon, SK, S7N 5C9, Canada
Telephine: (306) 966-4886, Facimile: (306) 966-4884
CMPT 145
Summer-Spring 2019
Principles of Computer Science
Question 2 (10 points):
Purpose: To re?ect on your experience planning and implementing an application.
Degree of Di?culty: Easy
In this question you will re?ect on your experience in Question 1. Answer the following questions about your
experience designing and implementing the application. You may use point form, and informal language.
Be brief. These are re?ection questions, and there is no right answer, and there is no need to go back to
Question 1 and change anything as a result of these questions. The intent of these questions is to get you
to think about the development process and the way you used them to complete your work.
1. (2 marks) Comment on your development strategy. For example, you could address the following
issues:
• In your development, did you follow the incremental model or did you think about your tests ?rst
so that your functions could be better tested in your unit tests (test-driven strategy)?
2. (2 marks) Comment on your design plan. For example, you could address the following issues:
• How much time did you spend on your design plan?
• Do you think you planned your application well enough?
• Did problems arise that you did not plan for? What kinds of problems (if any)?
• Were there functions you created that were not in your initial plan?
3. (2 marks) Comment on the implementation stage. For example, you could address the following
issues:
• Did you estimate the time you’d need to implement the application?
• Did the implementation take longer or shorter than you planned for, or expected?
• What took more time than you thought?
• What took less time than you thought?
4. (2 marks) Comment on your testing. For example, you could address the following issues:
• Did your test script ?nd errors in your functions?
• Did you discover errors in your functions during your veri?cation stage (when you were running
the completed application)?
• How long did you spend testing and debugging? If you spent more time than you expected, is
there any way you can try to reduce the time?
5. (2 marks) Comment on your use of time. For example, you could address the following issues:
• How much time total did you spend, from start to ?nish (excluding these re?ection questions)?
• Was that more or less than you expected? More or less than you planned?
Remember that the purpose of these questions is to help you learn from your experience.
Page 4
Department of Computer Science
176 Thorvaldson Building
110 Science Place, Saskatoon, SK, S7N 5C9, Canada
Telephine: (306) 966-4886, Facimile: (306) 966-4884
CMPT 145
Summer-Spring 2019
Principles of Computer Science
What to Hand In
Your answers to the above questions in a text ?le called a2_reflections.txt (PDF, rtf, docx or doc are
acceptable).
Be sure to include your name, NSID, student number, course number and laboratory section at the top of
all documents.
Evaluation
Each answer is worth 2 marks. Full marks will be given for any answer that demonstrates thoughtful re-
?ection. Grammar and spelling won’t be graded, but practice your professional-level writing skills anyway.
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