COS 126: Assignment 0. Hello, World

COS 126

Assignment 0

Programming Assignment

The purpose of this assignment is to introduce you to programming in Java and familiarize you with the mechanics of preparing and submitting assignment solutions. Every week you need to read BOTH the PROGRAMMING ASSIGNMENT and the CHECKLIST.

Your goal this week is to learn to use DrJava for editing programs, javac for compiling them, java for executing them, and Moodle for submitting them.

Hello, World. The purpose of this step is to set up your computer for developing Java programs.

Working at home. If you want to work on your home computer, follow the step-by-step instructions for your operating system: Windows, OS X, or Linux. If you're on the Princeton network, then you can download the files faster via our ftp server. If you are familiar with your operating system, you should be able to finish this part on your own. If you are hesitant, bring your laptop (and a network cable) to Friend 017. The labs are staffed in the evenings with knowledgeable TAs who can assist you. Don't be afraid to ask for help.
Working in a public cluster. If you prefer to work in one of the OIT public clusters follows the instructions for the Windows or OS X depending on your which type of computer you will be using, but skip the steps that involve installing software. If you are hesitant, work in Friend 016 or 017. The labs are staffed in the evenings with knowledgeable TAs who can assist you. Don't be afraid to ask for help.

Programming. Your job is to write two short programs on your own. We'll assume that you've already created, compiled, and executed HelloWorld.java by following the instructions in the previous part of the assignment.

Before completing this part, you should read Section 1.1 of Intro to Programming. Modify UseArgument.java to make a program HiFour.java that takes four names as command-line arguments and prints out a proper sentence with the names in the reverse of the order given, so that, for example,
```
% java HiFour Alice Bob Carol Dave
```
should output
```
Hi Dave, Carol, Bob, and Alice. 
```
Before completing this part, you should read Section 1.2 through page 22 of Intro to Programming. Write a program SumThree.java that reads in three integer command line arguments, x, y, and z. (You may assume that exactly three integer arguments will be entered when the program is run.) The program then outputs all three integers and their sum. For example,
```
java SumThree 2 5 8  
```
should output
```
2 + 5 + 8 = 15
```

Writeup. With each assignment you must submit a text file named readme.txt that is a narrative description of your work. We provide a readme.txt that you should use as a template. Download this file and answer all questions in the space provided. You will need to read the Assignment 0 checklist page, and the COS 126 Collaboration Policy in order to answer the related questions in your readme file. Note that every assignment will have a checklist; make sure to read it each week.

Browsing the course website. The next part of the assignment is to browse the COS 126 Web pages. The address is:

http://www.princeton.edu/~cos126

Cruise around the COS 126 Web site; it is essential that you understand what's where and how to get to it. Be sure to fill out the online questionnaire.

Submitting the assignment. The final part of the assignment is to submit HelloWorld.java, HiFour.java, SumThree.java and readme.txt via the Web submission system. To do this, launch your favorite browser and go to the COS 126 web page:

http://www.princeton.edu/~cos126

and select the HelloWorld assignment under Social Activities. After you submit your files, a Run Script button will appear. Be sure to hit it to check your program against our Java compiler. It should compile without errors or warnings; if not, fix the problem and resubmit the appropriate files. To submit a file, you must be registered for the course and know your NetID and OIT Email password.