📦 Part 5: Java Arrays – Store and Access Multiple Values

Ever wanted your code to remember a list of things? Like scores in a game, names of friends, or numbers from a quiz? That’s where arrays come in!

In Java, an array is like a row of boxes where each box holds a value — and each box has a number (called an index).

🧠 What Is an Array in Java?

An array lets you store multiple values in a single variable. Instead of writing this:

int score1 = 80;
int score2 = 90;
int score3 = 70;

You can write this:

int[] scores = {80, 90, 70};

Now you have all your scores in one place! Easy to manage. Easy to loop through.

🔢 How Do You Access an Array?

You use the index number. In Java, counting starts at 0. So:

System.out.println(scores[0]); // prints 80
System.out.println(scores[1]); // prints 90
System.out.println(scores[2]); // prints 70

⚠️ Important: If you try to access something that doesn’t exist (like scores[3]), you’ll get an error.

📥 Declaring Arrays in Java

There are two main ways to declare arrays:

// Method 1: Declare and assign values
String[] names = {"Rawisha", "Anna", "Leo"};

// Method 2: Declare first, then assign
int[] numbers = new int[3]; // makes room for 3 numbers
numbers[0] = 100;
numbers[1] = 200;
numbers[2] = 300;

🔁 Looping Through an Array

You can use a loop to print all values in an array:

for (int i = 0; i < scores.length; i++) {
    System.out.println("Score: " + scores[i]);
}

This works with any array! Just use array.length to get the number of items.

🎯 Real Example: Display Favorite Foods

String[] foods = {"Pizza", "Tacos", "Sushi"};

for (int i = 0; i < foods.length; i++) {
    System.out.println("I love " + foods[i]);
}

Output:

I love Pizza
I love Tacos
I love Sushi

👀 Common Mistakes to Avoid

• ❌ Forgetting arrays start at 0
• ❌ Trying to access an index that doesn’t exist
• ❌ Mixing up array types (int[] ≠ String[])

🧪 Mini Challenge: Store & Print 5 Favorite Numbers

Create an array with 5 numbers and print them using a loop.

int[] myNumbers = {7, 14, 21, 28, 35};

for (int i = 0; i < myNumbers.length; i++) {
    System.out.println(myNumbers[i]);
}

🧭 What’s Next?

In Part 6, we’ll explore:

• How to create your own methods (aka reusable code blocks)
• What void and return mean
• Why breaking code into pieces makes everything easier

✨ You’re now storing and using data like a real coder. High five!

📌 Java Array Cheat Sheet

// Declare and assign
int[] ages = {21, 25, 30};

// Access item
System.out.println(ages[0]);

// Get array length
System.out.println(ages.length);

// Loop through array
for (int i = 0; i < ages.length; i++) {
    System.out.println(ages[i]);
}