Computer Science II

Lab 2.0 - Operators and Conditions

An introduction to the operators and conditions in the Java programming language.

This is a lab used in Computer Science II (CSCE 156) for Fall 2024 in the School of Computing at the University of Nebraska-Lincoln.

Overview

Resources

• operator tutorial: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html
• if-else tutorial: http://download.oracle.com/javase/tutorial/java/nutsandbolts/if.html

Lab Objectives & Topics

Following the lab, you should be able to:

• use operators, such as +, -, *, and /
• use if-else statements to control the logical flow of the program.

Note that the lab may involve some concepts, classes, or methods not covered (yet) in the class. You should be able to complete the lab without fully understanding them. If you have any questions about them, please feel free to ask our LAs.

Peer Programming Pair-Up

At the start of each lab, you may find a team member by yourself or be randomly paired up with another student by a lab instructor. One of you will be designated the driver and the other is the navigator. Each week you should try to alternate: if you were a driver last week, be a navigator next, etc. If you prefer to work on this lab by yourself, that is fine too.

Note that each student must submit the code to GradeScope for grading.

1. Getting Started

Clone this project code for this lab from GitHub in Eclipse using the URL: https://github.com/lisongxu/CSCE156-Lab-Java-Cond. Please refer to Lab 1.0 for instructions on how to clone a project from GitHub in Eclipse.

2. Modifying the Statistics Java Programs

We continue to work on the Statistics Java programs. Note that the Statistics code in this lab is different from that of Lab 1, so you must clone the project code for this lab from GitHub.

Please modify Statistics.java as required below, so that StatisticsDemo.java outputs the correct answers.

1. Expand the src/main/java directory, then expand the unl.soc package, and then double-click on the Statistics.java file to open it.
2. Implement the getMax() method in the Statistics class. Use the getMin() method for directions on syntax.
3. Implement the getSum() method in the Statistics class. Use the other methods for direction on syntax.
4. Expand the src/main/java directory, expand the unl.soc package, and double-click on the StatisticsDemo.java file to open it.
5. Click on the "play" button to execute StatisticsDemo.java, and check the output in the "console" tab

3. Testing, Submitting, and Grading

3.1 Testing Locally

Before you submit your lab, you should run the JUnit tests locally to verify that your code is correct.

1. Expand the src/test/java directory, then expand the unl.soc package, and then double-click on the StatisiticsTests.java file to open it.
2. Run the test suite by clicking the usual "Play" button.
3. A report will be presented in a JUnit tab detailing which test cases pass and which fail along with the expected output and the actual output (for failed test cases).

3.2 Submitting

To submit your lab, do the following.

1. Go to Lab 2 on Canvas, and click the "Load Lab 2 in a new window" button which opens a GradeScope window for Lab 2.

2. Drag and Drop your modified Statistics.java, and then click the "Upload" button. Do not upload any other files.

3. Wait for the website to grade your code, and make sure that you pass all tests.

4. What if the test on GradeScope fails? Please test your program locally on your computer using the provided JUnit test suite, because the test on GradeScope is exactly the same as the provided JUnit test suite. Debugging your programs on GradeScope is not recommended because GradeScope gives very limited information.

3.3 Grading

For this lab, as long as you pass all the tests on GradeScope, you will get full points for the lab.