An array in Java is a data structure that stores multiple values of the same type in a single variable in contiguous memory locations.
Thank you for reading this post, don't forget to subscribe!- They are useful for storing and managing collections of data.
Key Points to Remember:
- Arrays have fixed size once created.
- Elements are stored in contiguous memory locations.
- First element is accessed by index 0
- All elements must be of the same data type
- Array access is O(1) time complexity.
- Arrays are objects in Java, stored in heap memory.
1.) One-Dimensional Arrays:
A one-dimensional array is a linear collection of elements of the same data type stored in a single row.
Syntax:
dataType[] arrayName = {value1, value2, value3, ...};Declaration and Initialization:
public class OneDArrayExample {
public static void main(String[] args) {
// Declaration
int[] numbers;
// Declaration with initialization
int[] numbers = {10, 20, 30, 40, 50};
System.out.println("Using for loop:");
for (int i = 0; i < numbers.length; i++) {
System.out.println("Element at index " + i + ": " + numbers[i]);
}
}
}Accessing Elements:
public class OneDArrayExample {
public static void main(String[] args) {
int[] arr = {10, 20, 30, 40, 50};
System.out.println(arr[0]); // Output: 10 (first element)
System.out.println(arr[4]); // Output: 50 (last element)
arr[2] = 100; // Modify element at index 2
}
}2.) Multidimensional Arrays:
Java supports arrays of arrays, commonly used to represent matrices or tables.
Two-Dimensional Arrays:
syntax:
dataType[][] arrayName = {
{value1, value2},
{value3, value4}
};Example:
public class TwoDArrayExample {
public static void main(String[] args) {
int[][] matrix = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
System.out.println("2D Array Output:");
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix[i].length; j++) {
System.out.print(matrix[i][j] + " ");
}
System.out.println(); // new line
}
}
}