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Learning Profile for Assignment #1, And Question #7
Name: Mo Khan
Student ID: 3431709
1. Problem Statement:
Douglas Hofstadter’s Pulitzer-prize-winning book Gödel, Escher, Bach contains many interesting mathematical puzzles.
In Chapter XII, Hofstadter mentions a wonderful problem that is well within the scope of the control statements in Java.
The problem can be expressed as follows:
* Pick some positive integer and call it n.
* If n is even, divide it by two.
* If n is odd, multiply it by three and add one.
Continue this process until n is equal to 1.
Hofstadter illustrates this process with the following example,
starting with the number n = 15:
15 is odd, so I make 3n+1: 46
46 is even, so I take half: 23
23 is odd, so I make 3n+1: 70
70 is even, so I take half: 35
35 is odd, so I make 3n+1: 106
106 is even, so I take half: 53
53 is odd, so I make 3n+1: 160
160 is even, so I take half: 80
80 is even, so I take half: 40
40 is even, so I take half: 20
20 is even, so I take half: 10
10 is even, so I take half: 5
5 is odd, so I make 3n+1: 16
16 is even, so I take half: 8
8 is even, so I take half: 4
4 is even, so I take half: 2
2 is even, so I take half: 1
As you can see from this example, the numbers go up and down, but eventually—at least for all numbers that have ever been tried—come down to end in 1.
In some respects, this process is reminiscent of the formation of hailstones,
which get carried upward by the winds over and over again before they finally descend to the ground.
Because of this analogy, this sequence of numbers is usually called the Hailstone sequence,
although it goes by many other names as well.
Write a program that reads in a number from the user and then displays the Hailstone sequence for that number,
followed by a line showing the number of steps taken to reach 1.
2. Description of the Code:
My first implementation of this algorithm used an iterative approach. I
later changed it to use a recursive approach because I felt the code was
a little bit easier to read and blowing the stack or performance wasn't
a big concern for this exercise.
The base case for the recursion is `n == 1`.
3. Errors and Warnings:
```bash
モ mvn test
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< ca.mokhan.comp268:assignment1 >--------------------
[INFO] Building assignment1 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- fmt-maven-plugin:2.8:format (default) @ assignment1 ---
[INFO] Processed 48 files (0 reformatted).
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ assignment1 ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /Users/mokha/development/gh/comp-268/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ assignment1 ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 24 source files to /Users/mokha/development/gh/comp-268/target/classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ assignment1 ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /Users/mokha/development/gh/comp-268/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ assignment1 ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 24 source files to /Users/mokha/development/gh/comp-268/target/test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ assignment1 ---
[INFO] Surefire report directory: /Users/mokha/development/gh/comp-268/target/surefire-reports
-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running ca.mokhan.comp268.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.006 sec
Running ca.mokhan.test.CandidateTest
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.05 sec
Running ca.mokhan.test.NumberTest
Tests run: 5, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.02 sec
Running ca.mokhan.test.EmployeeSavingsTest
Tests run: 6, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.006 sec
Running ca.mokhan.test.CartesianCoordinateSystemTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Running ca.mokhan.test.CommunicationTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running ca.mokhan.test.TaxReturnTest
Tests run: 12, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running ca.mokhan.test.BanffMarathonRunnerTest
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running ca.mokhan.test.AddressBookTest
Tests run: 12, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Running ca.mokhan.test.TriangleTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Running ca.mokhan.test.BonusOnSavingsTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Running ca.mokhan.test.HailstoneSequenceTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Results :
Tests run: 52, Failures: 0, Errors: 0, Skipped: 0
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.912 s
[INFO] Finished at: 2019-05-13T21:33:23-06:00
[INFO] ------------------------------------------------------------------------
```
4. Sample Input and Output:
Tests can be found in `HailstoneSequenceTest.java`.
5. Discussion:
|
