What is array? How arrays in java are different? Explain different types of arrays with example.

Array

An array is a collection of similar type of elements which has contiguous memory location.

 arrays in java are different are described below:-

Normally, an array is a collection of similar type of elements which has contiguous memory location.

Java array is an object which contains elements of a similar data type. Additionally, The elements of an array are stored in a contiguous memory location. It is a data structure where we store similar elements. We can store only a fixed set of elements in a Java array.

Array in Java is index-based, the first element of the array is stored at the 0th index, 2nd element is stored on the 1st index, and so on.

Types of Array in java

There are two types of array.

• Single Dimensional Array
• Multidimensional Array

1. Single Dimensional Array in java

Syntax to Declare an Array in java

dataType[] arr; or

dataType []arr; or

dataType arr[]; 

Instantiation of an Array in java

arr_ref_var-new datatype [size];

Let's see the simple example of a java array, where we are going to declare instantiate, initialize and traverse an array.

class Testarray

{

public static void main(String args[])

{

int a[]=new int[5];//declaration and instantiation

a[0]=10;//initialization

a[1]=20;

a[2]=70;

a[3]=40;

a[4]=50;

//printing array

for (int i=0;i<a.length; i++)//length is the property of array 

System.out.printIn(a[i]);

}

}

Output

10 

20

30

40

50

We can declare, instantiate and initialize the java array together by:

int a[]=[33,3,4,5);//declaration, instantiation and initialization

class Testarray

{

public static void main(String args[])

 {

int a[]=(3,7,9);//declaration, instantiation and initialization

//printing array

for(int i=0;i<a.length; i++)//length is the property of array 

System.out.printIn(a[i]);

}

}

output

3

7

9

2. Multidimensional array in java

In such cases, data is stored in row and column-based index which is also known as matrix form.

Syntax to Declare Multidimensional Array in java

dataType[][] ar;or

dataType [] []ar;or

dataType ar[][];or

dataType []ar[];

Example to instantiate Multidimensional Array in java

int[][] ar=new int [3] [3];//3 row and 3 column

Example of Multidimensional java array

Let's see the simple example to Declare instantiate, initialize and print the two-dimensional array.

import java.util.*;

class TestArray

{

public static void main(String args[])

{

int a[][]=new int[3][3];//declaration and instantiation

Scanner sc=new Scanner(System.in);

System.out.printIn("Enter elements");

for(int i=0;i<3;i++)

for(int j=0;j<3;j++)

a[i][j]=sc.nextint();

System.out.printIn("------Enter Elements Are----------\n");

for(int i=0;i<3;i++) ; 

{

for(int j=0;j<3;j++) ·

{

System.out.print(a[i][j]+" "); .. .

}

System.out.printIn();

}

}

}