Assignment 1

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Assignment 1

Objectives

● Introduction to Java

● Review methods, loops, and arrays

● Testing methods in Java

Introduction

In this assignment, you will write and test a set of methods. You are provided with a tester that calls the methods with a set of different inputs, and compares the value returned from the method with an intended result.

Some of the methods are completed for you, but the majority of them you will need to write yourselves until all of the expected results match the results actually returned.

Quick Start

1. Download A1Tester.java and A1Exercises.java into the same directory.

2. Read A1Tester.java and A1Exercises.java carefully. A1Tester.java contains all of the tests; it is the file you will compiling and executing. A1Tester.java contains all of the methods you will need to implement to complete the assignment.

a. Compile and run the A1Tester program from the directory you downloaded the files to.

    To compile:   javac A1Tester.java

    To run:          java A1Tester

b. The output should show that some tests are passing, but some are failing. Find the method with failing tests, fix the method, then recompile and rerun the tester until the tests pass. See the section below entitled Understanding the Test Programs for more information.

3. Implement each method in A1Exercises.java, by repeating the following steps:

a. Uncomment a test in the corresponding method in A1Tester.java

b. Compile and run A1Tester to ensure you have defined the method correctly.

c. Implement the method by completing the code within the method

d. Compile and run until all tests for the method pass.

CRITICAL: You must name the methods in A1Exercises.java as specified in the documentation (above the purpose) or you will receive a zero grade for that method (as the tests will not compile correctly). You cannot use java.util.Arrays methods or you will receive a zero grade for that method.

Submission and Grading

Submit A1Exercises.java with your name and student ID at the top of the file using BrightSpace.

If you chose not to complete some of the methods required, you must provide a stub for the incomplete method(s) in order for our tester to compile. I have provided some examples of a stub for you (numFactors and isPrime). Notice that these methods have a correct signature (name, return type, and parameter list), allowing the tester to call the methods, but their implementation is not correct. If you submit files that do not compile with our tester, you will receive a zero grade for the assignment. It is your responsibility to ensure you follow the specification and submit the correct files. Additionally, your code must not be written to specifically pass the test cases in the tester, instead, it must work on all valid inputs. We may change the input values when we run the tests and we will inspect your code for hard-coded solutions.

Be sure you submit your assignment, not just save a draft. ALL late and incorrect submissions will be given a ZERO grade. A reminder that it is OK to talk about your assignment with your classmates, but not to share code electronically or visually (on a display screen or paper). We will be using plagiarism detection software.

Understanding the test program

A1Tester.java tests your implementation of A1Exercises.java

The first things you should do after downloading the source files is to compile and run the test program:

Compile the test program by typing:   javac A1Tester.java

Run the test program by typing:         java A1Tester

You should see the following output:

Testing isFactor(3,3)

Expected: true

Returned: true

Testing isFactor(3,2)

Expected: false

Returned: false

Testing isFactor(8,2)

Expected: true

Returned: true

Testing isFactor(42,5)

Expected: false

Returned: false

Testing isFactor(102,17)

Expected: true

Returned: true

Testing calcPower(2,0)

Expected: 1

Returned: 1

Testing calcPower(2,3)

Expected: 8

Returned: 8

Testing calcPower(5,4)

Expected: 625

Returned: 625

Testing calcPower(13,2)

Expected: 169

Returned: 169

Testing numFactors(1)

Expected: 1

Returned: 0

Testing numFactors(4)

Expected: 4

Returned: 0

Testing numFactors(24)

Expected: 8

Returned: 0

Testing numFactors(51)

Expected: 4

Returned: 0

The first 27 lines are the output from the two methods implemented for you (isFactor and calcPower). As you can see, all of the returned results match the expected results, as the methods are implemented correctly. The tests for these two methods are written in A1Tester.java but the implementation for them is found in A1Exercises.java.

The next 12 lines are reporting that the current implementation is failing in the testNumFactors method when the numFactors method is called at lines 121, 127, 133, and 139. This is because we have only provided you with a stub for the numFactors method (it compiles and runs correctly, but there is a logic error in the implementation).

You will need to complete the implementation of all methods specified in A1Exercises.java. At this point, there is only documentation for each method, specifying the method name, purpose, number and types of arguments, and return type. Once you complete the implementation of a method, the returned result should match the expected result when you run the associated tests in A1Tester.java.