Java Intro #

This lab will walk you through setting up the IntelliJ Integrated Development Environment (IDE) and introduce you to the the basics of Java.

[0] Setup #

GitHub Configuration #

You will have received an email inviting you to join. You can also log in to github.com to accept the invitation.

💻 Select [Projects] > [Get from VCS]

💻 Select [Github]

💻 Click [Authorize]

Clone the Repository #

💻 select [Projects] > [Get from VCS] > [Repository URL] #

Be sure to change yourgithubusername to your actual GitHub username.

https://github.com/isf-dp-cs/lab_intro_yourgithubusername

Cannot Find JDK 17 - Fix click to expand ⬇️

💻 Select [File] > [Project Structure]

💻 From the SDK: dropdown, select Java 21

[1] Variables #

In Java, you have to specify the data type of each variable as you declare it, like this:

int videosWatched = 353;

Java has 8 primitive data types:

You can print variables and text to the console like this:

System.out.println("Number of videos watched: " + videosWatched);

💻 Add each of the following variables to your code, and print each one to the console. Be sure to use an appropriate data type.

// add a variable that stores your username
// add a variable that stores the number of videos youve uploaded
// add a variable that stores the average rating you give to videos
// add a variable that stores the theme setting as 'D' 'L' or 'A' for dark mode, light mode, or auto
// add a variable that stores whether you are signed in or not
// add a variable that stores the name of your country

[2] Strings #

Strings are more complex objects that come with certain features. Here are some examples:

String firstName = "John";
String lastName = "Doe";
System.out.println(firstName + " " + lastName); // add Strings together

String txt = "Hello! World";
int length = txt.length(); // get the length of a String

String first = "java programming";
String second = "java programming";

boolean result1 = first.equals(second); // compare first and second Strings

String txt = "Hello World";
char letter = txt.charAt(2); // returns character at index 2

ANSI Codes #

ANSI escape codes are special codes that can change the formatting when you print to the console

String yellowBackground = "\u001b[43;1m";
String reset = "\u001b[0m";
System.out.println(yellowBackground + "the sun is yellow" + reset);

The 256 Background Colors follow a simple forumula: \u001b[48;5; + n + m

[3] Conditionals #

User Input #

In java, you get user input like this:

Scanner scanner = new Scanner(System.in); // create a Scanner object
System.out.print("Are you having a good class so far? (y/n)");
String input = scanner.nextLine(); // get the user input

Modulo #

Just like in pseudocode, we can use the modulo operator to calculate the remainder of division. In java, we will use the % operator for mod.

int a = 15;
int b = 8;
int remainder = a % b; // calculate the remainder

• ask the user for their name
• ask the user for their favorite color
• ask the user for their second favorite color
• print out the user’s name, alternating between the two colors for each letter

[4] Wordle #

Now it’s time to put all your new skills to good use! You will be coding the game Wordle.

Looping #

Right now, the code picks a random 5-letter word, and allows the user a single guess. Not much of a game!

💻 Add a loop to the code, so that the user gets 6 guesses. You can reference your code from the other files to write your loop.

Highlight #

A big part of Wordle is the feedback from the game. After each guess, the user is shown their guess, and each letter is highlighted according to these rules:

• GRAY backround: guess letters not included in the word
• YELLOW backround: guess letters in the wrong location
• GREEN backround: guess letters in the correct location

End the loop early #

Right now, the user will be asked for 6 guesses no matter what. However, if they guess correctly, the loop should end early. Here are three examples of while loops:

// java while loop
while (i < 6) {
	System.out.println("Hello World");
	i++;
}

// java while loop with OR logic 
while (i < 6 || i < 1) {
	System.out.println("Hello World");
	i++;
}

// java while loop with AND logic 
while (i < 6 && i > 0) {
	System.out.println("Hello World");
	i++;
}

[5] Deliverables #

⚡✨

💻 Push your code to GitHub.

Include a descriptive commit message.

✋ If you would like teacher feedback, begin your commit message with #feedback