CS 342 Homework#1  Maven and Java

CS 342 Homework#1 
Maven and Java

Description:
In this homework, you will run a Maven project in your development environment of
choice. You will also create a new .java file with a few methods
Implementation Details:
What you have:
Download the zip file from Blackboard and go to the HomeworkOne directory. This is the
Maven project you will be working with. It is a small program that can calculate some
basic statistics (mean, median and standard deviation) from numbers read in from a text
file.
Take a look in the src/main/java folder. You will find two files: HomeworkOne.java and
Statistics.java. HomeworkOne.java just contains the main method. You will find some
code there but no need to change it.
Statistics.java is a class that reads in values from a file into an array. This class makes
calls to a StatFormulas class where the actual methods for calculating mean, median
and standard deviation will be located. You should notice that these method calls are
being made by the class name not a specific instance of that class. That means that
every method in the StatFormulas class will be static; creating a so called “static” outer
class. You should also notice that there is no StatFormulas.java file in your directory.
****You will be implementing that class; more on that in a bit.****
If you take a look at src/main/resources, you will find the two text files, values.txt and
values2.txt that this program uses to test the methods in the StatFormulas class.
Now take a look in the src/test/java directory and look at the StatMethodTest.java file.
This is a Junit5 test file. We will be doing unit tests with Junit5 soon but for now, you just
need to know that this is where the test cases are. Notice that for each file, 5 values and
6 values, we are testing the methods for mean, median and standard deviation (std) you
will write in the StatFormulas class you create.
Finally, take a look at the pom.xml file in the root directory, HomeworkOne. This
contains all of the dependencies this project needs to run.
CS 342 Homework#1 Fall 2019
What you need to do:
1) In the src/main/java directory, create a new java file called StatFormulas.java. This
file will have one class defined in it: public class StatFormulas
2) Inside of the StatFormulas class you need to implement the following methods:
public static double mean(double values[])
public static double median(double values[])
public static double std(double values[])
These are basic statistics formulas that are easily found if you are not familiar with
them. You will notice that your data is read into arrays of doubles. There are better data
structures in Java but since we have not covered them yet, we will stick with arrays
which everyone should be comfortable with. There are some helpful methods of the
Java Array class if you choose to use them. For instances; you will notice this line in the
constructor of the Statistics class:
Arrays.parallelSort(values);
This is a static method of the Array class that sorts an array. You will also find length
helpful.
How to develop this project:
You will need to import this project, the HomeworkOne directory, as a Maven project in
the IDE of your choice or just go to that directory from the command line. You can run
the Maven commands:
clean: removes all class files and reports.
test-compile: compiles files in the src/test/java directory
compile: compiles files in the src/main/java directory
test: runs all test cases
For each method you write, you should compile your project and run the tests. If the
method is correct, you will pass the two tests for that method (run with the values from
the text files).
You must also add the ability to run main in the pom.xml file. You do this by adding the
following line in the properties section:
 <exec.mainClass>HomeworkOne</exec.mainClass>
Run main with the following Maven command: exec:java
CS 342 Homework#1 Fall 2019
Electronic Submission:
Put the Maven template folder with your files in a .zip and name it with your netid +
MavenJava: for example, I would have a submission called mhalle5MavenJava.zip, and
submit it to the link on Blackboard course website.
Assignment Details:
Late work on a homework is NOT ACCEPTED. Anything past the deadline will result in
a zero.
We will test all homework on the command line using Maven 3.6.1.
You may develop in any IDE you chose but make sure your homework
can be run on the command line using Maven commands. Any
homework that does not run will result in a zero. If you are unsure
about using Maven, come see your TA or Professor.