Recitation 2 for CS160

Recitation R2 - Eclipse
Fall 2013

CS160: Foundations in Programming

The purpose of this lab is to learn the basics of using the Eclipse IDE and Java:

Get your Eclipse environment up and running
Write a couple of Java programs in Eclipse
Understand Java expressions
Submit recitation work to RamCT
Submit a Java program to Checkin on course website

Using Eclipse

Eclipse makes beginning programming easier by compiling and running your programs in a single step. Your TA will go over setting up Eclipse and your workspace.

To start Eclipse, find and click on the Eclipse Icon.
Select the Window→ Open Perspective→ Java
- You can change windows as need be to fit your work-flow.
- If your perspective ever gets too donked up, you can reset your perspective by going to Window→ Reset Perspective
Close the "Welcome" window if it doesn't disappear automatically.
Create a default comment header by going to Window→ Preferences→ Java→ Code Style→ Code Templates→ Code→ New Java files and putting a line for file name, your name, the class, and your email

Your TA will guide you in creating a project called P1 and class for starting the P1.

Creating a new project:
- Create a new project using the File→ New→ Project, and name it P1.
- Right click on P1 in the Package Explorer tab and choose New→ Class.
- Name it "P1" (Eclipse will add ".java" automatically) and type the following code between the brackets under "main":
  
  System.out.println( "Hello World!" );
Your code should look like this:
```
// P1 Assignment
// Author: Chris Wilcox
// Date:   8/26/2013
// Class:  CS160
// Email:  wilcox@cs.colostate.edu

public class P1
{
    public static void main( String[ ] args )
    {
        System.out.println( "Hello World!" ); 
    }
}
```
You can now run your program by clicking the green "Play" shaped button on the toolbar.
Note that the output will appear in the Console window at the bottom.
You should see the program print "Hello World!" on the first line of the console.
For detailed tutoring on using Eclipse, check out the website Eclipse.

Program Submission via Checkin

Your TA will now walk through logging in to the course website, submitting your code, and viewing preliminary test results.

Remember that this was just setting up for P1 and that there is still more to do before it is complete.

Show your P1.java program to the TA to get credit for this portion of the lab.

Java Programming

Create a new Java Project named R2, and make a class named R2. Your GTA will help you to print out the values of the following mathematical expressions:

12 + 7
12 / 7
12.0 / 7.0
12.0 / 7
12 % 7
3 - 7 * 6
(3 - 7) * 6
0.1 + 0.2 - 0.3

NOTE: Remember to use System.out.println( ) to print out the values of the expressions.

Initially you can use numeric constants in the print statements, but before you complete the program add the integer and double variables and use them in the computation. For example:


    int var1 = 12;
    

    int var2 = 7;
    

    double var3 = 7.0;
    

    double var4 = 12.0;

In a comment block at the bottom of your program, answer the following questions:

Explain the difference (or lack of it) in the result of 12 / 7, 12.0 / 7.0 and 12.0 / 7.
Explain the difference (or lack of it) in the result of 3 - 7 * 6 and (3 - 7) * 6.
Explain the result of 0.1 + 0.2 - 0.3

Show your R2.java program to the TA for grading and submit to RamCT to get credit for this lab.

Recitation R2 - Eclipse Fall 2013

Using Eclipse

Program Submission via Checkin

Java Programming

Recitation R2 - Eclipse
Fall 2013