42889解析

Faculty of Engineering and Information Technology
School of Computer Science
42889
$XWXPQ 2022
Assessment Task 1
Individual programming project: Command-line calculator
Due 250DU202 2 at 11:5 9 pm
This project is worth 25% of the overall mark for this subject.
Objectives
The purpose of this project is to demonstrate competence in the following skills:
Program design
Array and string manipulation
Command line arguments
Creating classes and methods inSwift
Exception handling
Automated testing
These tasks reflect all the subject objectives.
The reference i mplementation takes about 200 li nes of co de. As part of your subject wor kload
assessment, it is estimated this project will take 22.5 h ours to complete.
Instructions
3.Use "Product > Test" to test your functionality.

4. Upload your submission to Canvas. Compress your Xcode project into a zip file and upload
   the file to "Assessment 1 subm ission." You may submit maximum 3 times until the final due
   date. The final submission you make in the one that will be marked.
   1 Fork the project template from Canvas into a private repository.
5. Implement the specified functionality in thecalc target.
   calc
   1
   12
   Specification
   You are to prepare a macOS command-line tool that will act as a simple calculator. The
   calculator will be run from the command line and will only work with integer numbers and the
   following arithmetic operators:
   percentage.
   . The operator is the modulus operator, not
   For example, if the program is compiled to , the following demonstrates how it will work
   In the command line, the arguments are a repeated sequence in the form
   and ending in a
   Hitting the enter key will cause the program to evaluate the arguments and print the result. In
   this case .
   The program must follow the usual rules of arithmetic which say:
6. The and operators must all be evaluated before the and operators.
7. Operators must be evaluated from left to right.
   For example, using Rule 1
   becomes
   which results in
   If we did not use Rule 1 then would become and then
   and finally . This is an incorrect result.
   If we do not use Rule 2 then the following illustrates how it can go wrong
8. • x / % %
     ./calc 3 + 5 - 7
     1
     x / % + –
9. • 4 x 3 – 6 6 x 3 – 6 18 – 6
     x
10. %
    4
    reference/calc
    Going from left to right we evaluate the first, which reduces the expression to 20 % 2
    which becomes . If we evaluated the first then the expression would reduce to 4 x 1
    which becomes . This is an incorrectresult.
    Remember, we are using integer mathematics when doing our calculations, so we get integer
    results when doing division. For example
    Also note that we can use the unary and operators. For example
    Your program must also check to make sure the command line arguments are valid. If not your
    program must generate an appropriate error message and then terminate with nonzero exit
    status.
    You should also check for division by zero errors and numeric out-of-bounds errors.
    As part of your program design, it is expected you will create classes to model the problem
    domain.
    Program Hints
11. Getting your program to solve expressions that only use the and operators is fairly
    easy. Iwould suggest you get your program working at this level before attempting to get
    it to work with the other operators.
12. While this problem can be solved using iteration, it is easier to solve using recursion.
    Reference Implementation
    The template contains a executable that you can compare your
    implementation against. Your implementation should work in exactly the same manner.
    Please note that it prints results to standard output and additional messages to standard error.
    Only standard output is used for functionality testing.
    Assessment
    Max score: 25 marks
    Functionality: 16 marks
    The Xcode project must unzip successfully and compile without errors.
    ./calc -5 / +2
    -2
    ./calc +2 - -2
    4
    ./calc 20 / 3
    6
13. –
14. –
    CalcTest
    Deduct 3 marks if there are any compilerwarnings.
    Deduct 1 mark for each failing test in the suite.
    Style: 3 marks
    Deduct up to 1 mark for bad orinconsistent indentation, whitespace, or braces.
    Deduct up to 1 mark for bad or misleading comments.
    Deduct up to 1 mark for unclear symbol naming.
    Design: 6 marks
    Good design consists of domain specific classes with good functional separation.
    x Functional separation
    o Is the problem broken down into functions, classes and different files?
    o Is each class addressing a meaningful problem domain?
    o An example of bad functional separation: Everything in one big file with very large
    functions and many global variables.
    x Loose coupling
    o Can parts of the code base be modified in isolation? Would changing one
    portion require significant changes throughout the code base?
    o Is data passed between components in a structured way?
    o An example of good loose coupling is when functionality can be re-used in
    multiple components and potentially different projects.
    x Extensibility
    o Would it be easy to add more functionality? (more operations, more
    numerical accuracy, interactivity, variables, etc)
    o Can extra functionality be added to the program with minimal changes.Such as
    supporting different levels of precedence?
    o Bad extensibility would involve many hard-coded strings that are used in
    multiple places.
    x Control flow
    o Are all actions of the same type handled at the same level?
    o Can another developer understand the logic flow of your program by reading the
    main entry point?
    o Bad control flow could be caused by exiting the program outside of the main routine.
    x Error handling
    o Are errors detected at appropriate places? Can they be collected somewhere
    central?
    o Are errors correctly thrown and caught? Are they appropriately handled in the
    main routine?
    o Is the user presented with meaningful errors when they do something
    incorrectly such as providing invalid input?
    x Marker's discretion
    Late submission
    Deduct 1 mark per 24 hours late (rounded up). Submissions will not be accepted after the Final
    Due Date (7 days after the standard due date).
    Please note: Regardless of how many times you have submitted your project, if your final
    submission is after the due date it will be considered late and marks will deducted accordingly.
    An extension will only be granted if there is a fully documented reason which merits it. The
    documentation mustbepresented to theSubjectCoordinator beforethe duedate.Extensions
    after the Final Due Date will never be granted under any circumstance. If an extension is
    granted that means submission will be accepted up to the extension date without penalty. If an
    extension is granted, UTS Online will show the extended due date.
    Students may apply for special consideration if they consider that illness or misadventure has
    adversely aႇected their performance.
    Bug reports
    It is quite possible that errors or ambiguities may be found in the task specification,reference
    implementation,ortestsuite.Ifso,updateswillbeplacedonUTSOnlineandannouncements
    made regarding the amendment. It is your responsibility to keep up to date on such
    amendments and ensure you are using the latest version of the Task Specification.
    If you discover an error, ambiguity, or bug, you will receive the maximum "Marker's discretion"
    credit (1 mark). The following rules apply:
15. It must be a report on the currently posted version of the material.
16. It must be reported on the UTS Online discussion board to be accepted.
17. It must be a genuine bug. By genuine I mean it requires me to amend the material.
18. If a number of students post a report on the same bug, the first who posted will receive
    the mark.
19. No matter how many bug reports you make, you can only get 1 mark.
    Return of Assessed Project
    It is expected that marks will be made available one week after the final due date via
    Canvas. You will also be given a copy of the marking sheet showing a breakdown of the
    marks and feedback.
    Acceptable Practice vs Academic Malpractice
    Students should be aware that there is no group work within this subject. All work must be
    individual. However, it is considered acceptable practice to adapt code examples found in
    the lecture notes, labs and the text book for the assignment. Code adapted from any other
    source, particularly the Internet and other student assignments, will be considered
    academic malpractice. The point of the assignment is to demonstrate your understanding
    of the subject material covered. It's not about being able to find solutions on the Internet.
    You should also note that assignment submissions will be checked using software that
    detects similarities between students programs.
    Participants are reminded of the principles laid down in the "Statement of Good Practice
    and Ethics in Informal Assessment" in the Faculty Handbook. Assignments in this subject
    should be your own original work. Any collaboration with another participant should be
    limited to those matters described in the "Acceptable Behaviour" section. Any
    infringement by a participant will be considered a breach of discipline and will be dealt
    with in accordance with the Rules and By-Laws the University. The Faculty penalty for
    proven misconduct of this nature is zero marks for the subject. For more information, see
    UTS Policy on Academic integrity, plagiarism and cheating
    Queries
    If you have a question, please contact the instructor as soon as possible. Please do not send
    email in HTML format or with attachments. They will not be read or opened. Only emails sent in
    plain text format will be read. Emails without subject lines will be automatically deleted by the
    junk mail filters I have in place.
    If the answer to your questions can be found directly in any of the following:
    subject outline
    task specification
    UTS Canvas discussion board
    You will be directed to these locations rather than given a direct answer.
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