What is an Array in Java?

An array is a collection of elements of the same type stored in a contiguous memory location. Arrays have a fixed size once defined.

Declaring and Initializing Arrays

1️⃣ Declaration

int[] numbers;       // Preferred way
String names[];      // Also valid

2️⃣ Instantiation (Create with size)

numbers = new int[5];   // Array with 5 elements, default value 0

3️⃣ Declaration + Initialization

int[] scores = new int[3];          // [0, 0, 0]
String[] cities = {"Delhi", "Mumbai", "Chennai"};

Accessing Array Elements

• Use index (starts from 0).

System.out.println(cities[1]);     // Output: Mumbai
scores[0] = 90;                    // Assigning value

Example 1: Integer Array

public class ArrayExample {
    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40, 50};
        System.out.println("First element: " + numbers[0]);    // 10
        System.out.println("Third element: " + numbers[2]);    // 30
    }
}

Example 2: Loop Through an Array

Using a for loop:

for (int i = 0; i < numbers.length; i++) {
    System.out.println("Element at index " + i + ": " + numbers[i]);
}

Using an enhanced for loop:

for (int num : numbers) {
    System.out.println(num);
}

Example 3: String Array

public class StringArray {
    public static void main(String[] args) {
        String[] fruits = {"Apple", "Banana", "Mango"};

        for (String fruit : fruits) {
            System.out.println(fruit);
        }
    }
}

Array Properties

Bonus: Multidimensional Array

int[][] matrix = {
    {1, 2, 3},
    {4, 5, 6}
};

System.out.println(matrix[1][2]);   // Output: 6