A single-dimensional array in Java is a linear data structure that holds a fixed-size sequence of elements of the same type. It is one of the most commonly used data structures in Java, particularly when you need to store and access a list of related data elements, such as numbers, strings, or objects.
Characteristics of Single-Dimensional Arrays:
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Fixed Size: Once an array is declared, its size cannot be changed.
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Index-Based Access: Elements in an array are accessed via their index, with the first element having an index of 0.
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Homogeneous Data: All elements in an array are of the same type (e.g., all integers, all strings, etc.).
Syntax for Declaring and Initializing a Single-Dimensional Array:
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Declaration:
type[] arrayName;Code language: CSS (css)type: The data type of the elements (e.g.,int,String,double).arrayName: The name of the array variable.
Initialization:
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You can initialize an array when you declare it or later in the program.
Example 1 (Declaration and Initialization at the Same Time):
int[] numbers = new int[5]; // Creates an array with 5 elements, initialized to 0
numbers[0] = 10;
numbers[1] = 20;
numbers[2] = 30;
numbers[3] = 40;
numbers[4] = 50;Code language: JavaScript (javascript)Example 2 (Declaration First, then Initialization):
int[] numbers = new int[5]; // Creates an array with 5 elements, initialized to 0
numbers[0] = 10;
numbers[1] = 20;
numbers[2] = 30;
numbers[3] = 40;
numbers[4] = 50;Code language: JavaScript (javascript)Accessing Elements in a Single-Dimensional Array:
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Array elements are accessed using indices, which start from 0.
Example:
System.out.println(numbers[0]); // Output: 10
System.out.println(numbers[4]); // Output: 50Code language: JavaScript (javascript)Iterating Through a Single-Dimensional Array:
You can loop through an array using a for loop or an enhanced for loop (also known as the “for-each” loop).
Example using a for loop:
for (int i = 0; i < numbers.length; i++) {
System.out.println(numbers[i]);
}Example using an enhanced for loop:
for (int number : numbers) {
System.out.println(number);
}Key Methods for Arrays:
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length: Thelengthproperty gives the number of elements in the array.
System.out.println(numbers.length); // Output: 5Code language: JavaScript (javascript)2. Arrays.toString(): You can use the Arrays.toString() method (from java.util.Arrays) to print an array in a human-readable format.
System.out.println(Arrays.toString(numbers)); // Output: [10, 20, 30, 40, 50]Code language: JavaScript (javascript)Example Program Using a Single-Dimensional Array:
import java.util.Arrays;
public class ArrayExample {
public static void main(String[] args) {
// Declare and initialize the array
int[] numbers = {1, 2, 3, 4, 5};
// Accessing elements in the array
System.out.println("First element: " + numbers[0]);
System.out.println("Last element: " + numbers[4]);
// Iterating over the array using a for loop
System.out.println("\nUsing for loop:");
for (int i = 0; i < numbers.length; i++) {
System.out.println(numbers[i]);
}
// Iterating over the array using the enhanced for loop
System.out.println("\nUsing enhanced for loop:");
for (int num : numbers) {
System.out.println(num);
}
// Printing the array using Arrays.toString()
System.out.println("\nArray contents: " + Arrays.toString(numbers));
}
}
/*
First element: 1
Last element: 5
Using for loop:
1
2
3
4
5
Using enhanced for loop:
1
2
3
4
5
Array contents: [1, 2, 3, 4, 5]
*/A single-dimensional array is a simple yet powerful data structure for storing a sequence of elements in Java. Understanding how to declare, initialize, access, and manipulate arrays is essential for working with many Java programs.