Purpose: The first lab assignment is an opportunity to test your GitHub Classroom environment, making sure you understand how to begin writing programs using a codespace. This will also be your first look at variables, which will be a fundamental part of all your programs.
Learning Objectives:
In-Class 1: Variables are used to hold values in your programs. This allows you to set the value once and use that value many times later. For example, a String variable is used to hold a sequence of characters (think of it like a string of words). Instead of rewriting that sequence of characters repeatedly, you only need to use the variable.
To make this String variable, you must declare it. This variable declaration looks like the following:
String message;This includes the String type, the name of the variable, and the terminating semi-colon. There are rules about variable names to learn later, but you can effectively name the variable whatever you like. To give this variable a value, you must assign that value to it. This variable assignment looks like the following:
message = "Welcome to Java!";The equals sign is known as the assignment operator. The variable is placed on the left-hand side, and the value is placed on the right-hand side. Also notice that you do not specify the String type. That type only ever needs to be stated when you declare the variable. Once this variable has a value, you can now use it. The simplest use-case for a String is to print it:
System.out.println(message);Variables are placed into statements in order to use them, such as the placement of the message variable in this print statement. You will learn more about the rules for placing variables into statements later. And again, remember that you do not specify the String type when using a variable.
Before you start the main lab, try this quick exercise in your codespace:
- In the Java file named
InClass1_FirstName_LastName.java(replace with your name). Be sure to change this in the class header as well, on Line 9. - Inside the file, declare a String variable, assign it a value (like your favorite quote or greeting), and print it to the console.
- Run your program to see the output.
This is a simple way to practice using variables and printing output before you begin the full lab assignment below.
For this lab only, the Java file is already created for you, named Lab1_FirstName_LastName.java. Replace FirstName and LastName with your actual name, and do the same in the class header on Line 9. Note: In future labs, you will be responsible for creating the .java file yourself, including writing the correct class and method headers. This is an important skill for building your own programs from scratch.
Example: If your name is John Smith, create Lab1_John_Smith.java
The file Lab1_FirstName_LastName.java is already created for you. Make sure to update the filename and class name with your actual first and last name.
Fill in the header comments at the top of the file with your name, today's date, and a brief purpose statement. Confirm the class name matches your filename.
Inside the main method, declare a String variable. Choose a meaningful name, such as message, statement, or whyStatement.
Assign a value to your variable. Write a sentence about why you want to be a programmer or your goals for this course.
Use System.out.println() to print your variable to the console.
Add at least one comment in your code explaining what your code does or why you wrote it that way. This helps build good habits for future labs.
/**
* Name: [Your Name]
* Date: [Today's Date]
* Purpose: Lab 1 - Introduction to Variables and GitHub Classroom
*/
public class Lab1_YourFirstName_YourLastName
{
public static void main(String[] args)
{
// Declare a String variable
// Assign your personal statement to the variable
// Print the variable to the console
}
}- Open the terminal in your codespace (Terminal → New Terminal)
- Compile your program:
javac Lab1_YourFirstName_YourLastName.java
- Run your program:
java Lab1_YourFirstName_YourLastName
- Open your Java file
- Look for the "Run" button that appears above your main method
- Click it to compile and run your program automatically
When you run your program, you should see your personal statement printed to the console. For example:
I want to learn how to solve real-world problems with code.
If you see your message, your program is working correctly!
- Compilation errors: Check that your filename, class name, and method headers match the instructions. Make sure you end statements with a semicolon.
- No output: Confirm you used
System.out.println()and assigned a value to your variable. - Wrong filename/class name: Both should use your actual first and last name, and match each other.
- Typos: Double-check spelling, capitalization, and punctuation.
- Use VS Code's Source Control panel:
- Click the Source Control icon in the left sidebar
- Type a commit message
- Click "Commit" then "Sync Changes"
After pushing your changes, visit your assignment repository on GitHub Classroom. Confirm that your latest code and commit message appear, and that your files are named correctly. Check the "Actions" tab to see if your code passed the autograding tests.
Once you have verified your submission on GitHub Classroom, copy the URL of your assignment repository and submit this GitHub repository link to Blackboard as confirmation that you are DONE.
Lab1.java (100 points total): Criteria: Make sure you have the following in your program:
• String declaration (30 points) • String assignment (40 points) • println() statement (30 points)
InClass1.java (Participation points): Full credit is awarded for completing and submitting the in-class exercise, regardless of output or minor errors.
Remember: This is your first programming assignment! Take your time, ask questions, and don't worry if it takes a few tries to get everything working. The goal is to learn the process and get comfortable with the tools you'll be using throughout the course.
Important: Do NOT edit or tamper with any test files (such as Lab1Test.java or InClass1Test.java). These files are used for autograding and checking your work. In future labs, if test files appear to be modified, you may be contacted to verify the integrity of your submission.