EECS1022-Lab 2 Selections/Conditions Elementary Programming Solved

1         Task 1: Complete Weekly Java Tutorial Videos
•   For Lab2, you are assigned to study Week 3 Part A to Part G of the Java tutorial series:

https://www.youtube.com/playlist?list=PL5dxAmCmjv_6UHGyyTZTNorPaBgcXpauf To reference tutorial videos from the previous weeks, see:
 
https://www.youtube.com/playlist?list=PL5dxAmCmjv_6wy2m0yq2wObIWPz4tAxW6
 
These Java tutorial videos assigned to you are meant for you to:

1.   Obtain extra hands-on programming experience on Java, supplementing your weekly lectures.

2.   Complete the lab assignment with the necessary skills and background.

Parts A to G are directly relevant to this lab. Parts F and G from Week 2 are also relevant to your Lab2.

Though we do not require the submission of the weekly Java tutorial project (like in Lab0), examples and insights discussed in these tutorials will be covered in your (written and programming) tests and exam: should you decide to skip the weekly tutorial videos, it would be your choice.

As you study through the example Java classes in the tutorial videos, you are advised to type them out (but absolutely feel free to add new Java classes to experiment) on Eclipse.

•   You can find the iPad notes of illustrations from the tutorial videos here: https://www.eecs.yorku.ca/˜jackie/teaching/tutorials/notes/EECS1022%20Tutorial%20on%20Java.pdf

•   This week’s Java tutorial shows some example of nested if-statement. Optionally, if you wish to study more about nested if-statement, refer to these two videos:

– A simple bank application: Nested If-Statements Version 1:

https://www.youtube.com/watch?v=w3YojTfDTeA&list=PL5dxAmCmjv_5NRNPG3OiWZWAqmvCjiLfG&index=19 – A simple bank application: Nested If-Statements Version 2:

https://www.youtube.com/watch?v=FI0d8XKBymg&list=PL5dxAmCmjv_5NRNPG3OiWZWAqmvCjiLfG&index=20

2         Task 2: Complete Programming Exercises
Starting Task 2 should mean that you have already completed the weekly Java tutorial videos (Section 1).

2.1        Step 1: Download and Import the Starter Project
1.   Download the Eclipse Java project archive file from eClass: EECS1022W21Lab2.zip

2.   Launch Eclipse and browse to EECS1022-W21-workspace as the Workspace then click on Launch, e.g.,

 

3.3 Choose Select archive file. Make sure that the EECS1022W21Lab2 box is checked under Projects.

 

2.2        Step 2: Programming Tasks
From the Package Explorer of Eclipse, your imported project has the following structure.

•   You can manually test the assigned methods using the corresponding console application classes in package consoleapps. These classes are completed and given to you. See below for more descriptions.

•   Your goal is to pass all JUnit tests given to you (i.e., a green bar). To run them, as shown in the Java tutorials on Week 1, right click on TestUtilities.java and run it as JUnit tests. Of course, none of the given tests would pass to begin with.

 

How to Deal with a Failed JUnit Test? From the JUnit panel from Eclipse, click on the failed test, then double click on the first line underneath Failure Trace, then you can see the expected value versus the return value from your utility method.

 

2.2.1       Method to Implement: getRPSGameReport
Problem. You are asked to consider the rock-paper-scissors (RPS) game (for which it is assumed that you know how to play it). Rock is denoted by character ’R’, paper by ’P’, and scissors by ’S’. As a reminder: rock wins scissors, paper wins rock, and scissors wins paper.

Testing. Your goal is to pass all tests related to this method in the JUnit test class TestUtilities. These tests document the expected values on various cases: study them while developing your code. However, use the console application class RPSGameApp if you wish (e.g., use the input and expected values from the JUnit tests).

Let’s consider two example runs (where the same two players swap the order from one game to another):

Enter the name of player 1: Doraemon

Enter the name of player 2:

Edward Scissorhands

What does Doraemon play at round 1 (R, P, S)?

R

What does Edward Scissorhands play at round 1 (R, P, S)?

S

What does Doraemon play at round 2 (R, P, S)?

R

What does Edward Scissorhands play at round 2 (R, P, S)?

S

Game over: Doraemon wins! [Round 1: Doraemon wins (R vs. S) ; Round 2: Doraemon wins (R vs. S)]
•

Enter the name of player 1: Edward Scissorhands

Enter the name of player 2:

Doraemon

What does Edward Scissorhands play at round 1 (R, P, S)?

S

What does Doraemon play at round 1 (R, P, S)?

R

What does Edward Scissorhands play at round 2 (R, P, S)?

S

What does Doraemon play at round 2 (R, P, S)?

R

Game over: Doraemon wins! [Round 1: Doraemon wins (R vs. S) ; Round 2: Doraemon wins (R vs. S)]
•

In this 2nd example run:

–    The Round 1 result shows: Round 1: Doraemon wins (R vs. S).

–    More precisely, R vs. S shows that rock wins scissors, despite the order of the players.

–    That is, the left-hand side of vs. always shows the play that wins, not what player 1 (in this case Edward Scissorhands) plays.

–    A similar argument also applies to the Round 2 result.

Todo. Implement the Utilities.getRPSGameReport method. See the comments there for the input parameters and requirements. The String return value must conform to the expected format (otherwise your code will fail some JUnit tests). Here are some hints for you:

•   Read carefully the comments in the Utilitye class about what each input of method getRPSGameReport means. For example, invoking

Utilities.getRPSGameReport("Suyeon", "Yuna", ’R’, ’P’, ’S’, ’R’)

means: Suyeon is player 1, Yuna is player 2, player 1 plays rock and player 2 plays paper in Round 1, and player 1 plays scissors and player 2 plays rock in Round 2.

•   Do not modify the console application class RPSGameApp given to you: the string return value of the utility method getRPSGameReport must be a string like:

Game over: Doraemon wins! [Round 1: Doraemon wins (R vs. S) ; Round 2: Doraemon wins (R vs. S)]

•   As illustrated in the above 2nd example run, the left-hand side of vs. always shows the play that wins, not what player 1 plays.

•   Be mindful about the spellings (e.g., Game over, wins): they are case-sensitive.

•   Be mindful about the single spaces between words and after symbols such as :, !, ., and :.

•   After the phrase ‘‘Game over:’’ comes the game result: it only shows who wins.

•   Within the pair of square brackets [] comes the results of each round: it only declares who wins.

Hint. Study the 9 test cases in TestUtilites: they are arranged in a systematic (yet not complete) way.

Question. In order to exhaustively test this game, considering just how two players say Suyeon and Yuna may play in the two rounds, how many tests do we need? (Optionally, you may write extra test yourself as an exercise.)

2.2.2       Method to Implement: getTaxReport
After reading the problem description below, here is an illustration on the two example filers Jim and Jonathan:

https://www.youtube.com/watch?v=q2NT5x77hdg&list=PL5dxAmCmjv_7YgI2LgcwjWTHiNZSR-aQX&index=1.

Problem.      You are asked to consider an imaginary income tax scheme, where the calculation is based on:

1.   filing status (single filing or married filing)

2.   taxable income

Once the above information is given by the user, the tax is calculated based on the following scheme:

Tax Rate
Single Filing Status
Married Filing Status
                                                   10%                     $0 – $8,350                           $0 – $16,700

                                                   15%                $8,351 – $33,950                $16,701 – $67,900

                                                   25%                       $33,950+                               $67,900+

That is, a tax payer’s income is split into up to three parts, depending on how high their income is. Once split, each part of the income is taxed with the corresponding rate. For a single filer, the cutoff points are $8,350 and $33,950. For a married filer, the cutoff points are $16,700 and $67,900.

As an example, consider Jim who is a single filer and whose income is $186,476. Since his income is higher than the second cutoff point for a single filer (i.e., $33,950), his income will be split into 3 parts:

•   The first $8,350 is taxed with a rate of 10%.

•   The subsequent $(33,950 - 8,350) is taxed with a rate of 15%.

•   The final $(186,476 - 33,950) is taxed with a rate of 25%.

Important Exercise Before You Proceed: Try the tax calculation for Jonathan, who is a married filer and who has a lower income $33,500. How would his income be split with this lower income? How would his income tax then be calculated?

Testing. Your goal is to pass all tests related to this method in the JUnit test class TestUtilities. These tests document the expected values on various cases: study them while developing your code. However, use the console application class TaxComputationApp if you wish (e.g., use the input and expected values from the JUnit tests). Here are two example runs:

Enter your name: Alan

Alan, enter your filing status (1 -- Single Filing; 2 -- Married Filing):

1

Alan, enter your taxable income (an integer value): 186476

Single Filing: $42806.50 (Part I: $835.00, Part II: $3840.00, Part III: $38131.50)
Enter your name: Mark

Mark, enter your filing status (1 -- Single Filing; 2 -- Married Filing):

2

Mark, enter your taxable income (an integer value): 33500

Married Filing: $4190.00 (Part I: $1670.00, Part II: $2520.00)
1. 2.

Todo.    Implement the Utilities.getTaxReport method. See the comments there for the input parameters and requirements. The String return value must conform to the expected format:

•   Do not modify the console application class TaxComputationApp given to you: the string return value of the utility method getTaxReport must be a string like:

Married Filing: $4190.00 (Part I: $1670.00, Part II: $2520.00)

•   If an income is split into less than 3 parts, the missing part(s) will not be included in the string report.

•   You should first calculate the part(s) of tax of a given income, then calculate its sum, and then you must format each part and the sum as floating-point numbers with exactly two digits following the decimal point (e.g., 800.00, 789.10).

Hint. Use String.format(%.2f, someNumber) as shown in Week 1’s Java tutorials for this purpose.