Array Declarations in Java (Single and Multidimensional)

In Java, an Array is used to store multiple values of the same type in a single variable. There are two types of arrays in Java:

• Single-dimensional arrays
• Multi-dimensional arrays

In this article, we are going to discuss how to declare and use single and multidimensional arrays in Java.

Single-Dimensional Array

It is a collection of variables of the same type which is used by a common name. In an array, we can access each element with the help of an index.

Declaration of Single-Dimensional Array

The declaration of a single-dimensional array is:

dataType[] arrayName = new dataType[size];

Note: Here, dataType is the type of elements the array will store, arrayName is the name of the array variable, and size is the number of elements the array can hold.

Example:

We can write it in any way. Now, if declare the array like below:

Example:

Now, suppose we want to write multiple declaration of array variable then how we gonna do this.

Example:

When we are declaring multiple variable of same time at a time, we have to write variable first then declare that variable except first variable declaration. There is no restriction for the first variable.

Note: When we creates an array it is mandatory to pass the size of array, otherwise we will get compile time error. We can use new operator for creating an array.

Example:

Implementation of Single Dimensional Array

100
100
100

Now, we will discuss about Multidimensional Array in detail.

Multi-Dimensional Array

Suppose, we want to create mutli dimensional array of int data type.

Declaration of Mutli-Dimensional Array

The declaration of multidimensional array is:

dataType[][] arrayName = new dataType[rows][columns];

Note: Here, row is the number of rows and coloumn is the number of element in each row.

So, there are multiple ways to declare multidimensional array which are below with examples:

Example:

Now, suppose we want to write multiple declarations of array variable then we can use it like this.

Example:

Implementation of Mutli-Dimensional Array

Element at position (0,0): 100
Element at position (0,1): 100
Element at position (0,2): 100
Element at position (1,0): 100
Element at position (1,1): 100
Element at position (1,2): 100

Now, we are going to disucuss one more interesting thing that how to create one dimensional and two dimensional array without the help of new operator.

Example:

20
100 100 100 
100 100 100 
100 100 100 

Now, let's discuss, how to create one dimensional array and two dimensional array using new operator.

Example: