What is a Single and Multidimensional Array?
➢Single Array:
It is nothing but an object that holds the elements having same data type.
➢Multidimensional Array:
In simple terms, we can describe multidimensional arrays as an array of arrays.
Single Array:
When it comes to Java arrays, an array is a collection of like-typed variables i.e elements having same data type. Java arrays are different than arrays in C/C++. Some important points regarding java arrays are listed below.
In Java, all arrays are allocated dynamically.o Because arrays are objects in Java, we may use the object attribute length to determine their length. This differs from C/C++, where we use sizeof to find length.
o
A Java array variable can also be declared
like other variables with [] after the data type.
o
The array's variables are sorted, and each has an index starting at 0.
o
A static field, a local variable, or a method parameter can all be utilised with a Java array.
o
An array's size must be given using an int or short integer rather than a long number.
o
The direct superclass of an array type is
Object.
o
Every array type implements the Cloneable and java.io interfaces. Serializable.
Depending on the array's definition, it can include both primitive (int, char, etc.) and object (or non-primitive) pointers to a class. The actual values for primitive data types are stored in contiguous memory regions. The real objects are kept in a heap segment for class objects.
➢The
general form of a one-dimensional array declaration is :
type
var-name[];
OR
type[]
var-name;
➢Initializing an Array in
Java
Only a reference to an array is produced when an array is declared. You make an array like this to create or provide memory to the array: When it comes to one-dimensional arrays, the general form of new is as follows:
var-name = new type
[size];
int[] intArray = new
int[20];
When an array is declared, all that is produced is a reference to it. To generate or contribute memory to the array, you create an array like this: When it comes to one-dimensional arrays, new takes the following form:
➢Accessing Java Array
Elements using for Loop
The index of each element in the array is used to access it. The index starts at 0 and goes all the way to (total array size)-1. Java for Loop allows you to access all of the elements in an array.
for (int i = 0; i <
arr.length; i++)
System.out.println("Element at index
" + i + " : "+ arr[i]);
Multidimensional Array:
The simplest version of a multidimensional array is a two-dimensional array. For ease of understanding, we can think of a two-dimensional array as an array of one-dimensional arrays.
➢ Data in multidimensional arrays are stored in tabular
form.
Fig. Tabular Presentation Of 2-D Array
➢Declaration
● General form of declaring N-dimensional arrays:
data_type array_name [size1][size2]....[sizeN];
○ data_type: The data type that will be placed in the array.
○ array_name: Name of the array.
○ size1, size2,... ,sizeN: Dimensions and their sizes.
➢Examples:
○ Two dimensional array:
int two_d[10][20];
○ Three dimensional array:
int three_d[10][20][30];
We can declare a two dimensional integer
array say ‘x’ of size 10,20 as: int x[10][20];
Elements in two-dimensional arrays are
commonly referred by x[i][j] where i is the row number and ‘j’ is the column
number.
A two – dimensional array can be seen as a table with ‘x’ rows and ‘y’
column
○where the row number is in the range of 0 to (x-1)
○ and column number ranges from 0 to (y-1).
➢Initializing Two – Dimensional Arrays:
A Two-Dimensional array can be initialised in one of two ways.
First Method:
● int x[3][4] = {0, 1 ,2 ,3 ,4 , 5 , 6 , 7
, 8 , 9 , 10 , 11}.
○ There are three rows and four columns in the aforementioned array.
○ In the table, the components in the braces are retained in the same order as they occur in the braces.
○
The array will be filled in order, starting with the first four elements from the left in the first row, followed by the next four elements in the second row, and so on.
Better Method:
●
int x[3][4] = {{0,1,2,3}, {4,5,6,7}, {8,9,10,11}};
○ Nested brackets are used in this type of initialization.
○One row is represented by each set of inner braces.
○Because there are three rows in the previous example, there are three sets of inner braces.
➢Accessing Elements of Two-Dimensional
Arrays:
● In two-dimensional arrays, row and column indexes are utilised to access elements.●
Example: int x[2][1];● In the example above, the element in the third row and second column is represented.● Note: In arrays, if the array size is N,.
Its index will be from 0 to N-1. Therefore, for row index 2 row number is 2+1 =
3.● To print all the entries in a Two-Dimensional array, we can use nested for loops. We'll need two loops for the loops. One moves through the rows, while the other moves through the columns.
➢Three – dimensional Array (3D-Array)
A three-dimensional array is a more sophisticated version of a multidimensional array. For ease of understanding, a three-dimensional array can be thought of as an array of two-dimensional arrays.
Indirect Method of Declaration:
Declaration – Syntax:
data_type[][][] array_name = new data_type[x][y][z];
For example: int[][][] arr
= new int[10][20][30];
Initialization – Syntax:
array_name[array_index][row_index][column_index] = value;
For example: arr[0][0][0]
= 1;
Accessing Elements of
Three-Dimensional Arrays:
Elements in three-dimensional arrays are commonly referred by x[i][j][k]
where ‘i’ is the array number, ‘j’ is the row number and ‘k’ is the column
number.
3D array representation in tabular format: A three – dimensional
array can be seen as a tables of arrays with ‘x’ rows and ‘y’ columns where the
row number ranges from 0 to (x-1) and column number ranges from 0 to (y-1). A
three – dimensional array with 3 array containing 3 rows and 3 columns is shown
below:
Fig. Representation of 3-D array.
Comparison Between Types Of Arrays in Java
An array is a data structure that allows you to store variables of similar data kinds in close proximity. The array's key benefit is random access and cache friendliness. The array can be divided into three types:
·
One Dimensional
(1D) Array
·
Two Dimension (2D)
Array
·
Multidimensional
Array
· ➢
One Dimensional
Array:
o
It's a collection of variables with comparable data kinds.
o
It allows for random access, and all of the elements can be found by
their index.
o
The array's size is predetermined.
➢Single Array:
➢Multidimensional Array:
In simple terms, we can describe multidimensional arrays as an array of arrays.
Single Array:
When it comes to Java arrays, an array is a collection of like-typed variables i.e elements having same data type. Java arrays are different than arrays in C/C++. Some important points regarding java arrays are listed below.
o A Java array variable can also be declared like other variables with [] after the data type.
o The array's variables are sorted, and each has an index starting at 0.
o A static field, a local variable, or a method parameter can all be utilised with a Java array.
o An array's size must be given using an int or short integer rather than a long number.
o The direct superclass of an array type is Object.
o Every array type implements the Cloneable and java.io interfaces. Serializable.
Depending on the array's definition, it can include both primitive (int, char, etc.) and object (or non-primitive) pointers to a class. The actual values for primitive data types are stored in contiguous memory regions. The real objects are kept in a heap segment for class objects.
➢The general form of a one-dimensional array declaration is :
type
var-name[];
OR
type[] var-name;
➢Initializing an Array in Java
Only a reference to an array is produced when an array is declared. You make an array like this to create or provide memory to the array: When it comes to one-dimensional arrays, the general form of new is as follows:
var-name = new type
[size];
int[] intArray = new
int[20];
When an array is declared, all that is produced is a reference to it. To generate or contribute memory to the array, you create an array like this: When it comes to one-dimensional arrays, new takes the following form:
➢Accessing Java Array Elements using for Loop
The index of each element in the array is used to access it. The index starts at 0 and goes all the way to (total array size)-1. Java for Loop allows you to access all of the elements in an array.
for (int i = 0; i <
arr.length; i++)
System.out.println("Element at index " + i + " : "+ arr[i]);
Multidimensional Array:
The simplest version of a multidimensional array is a two-dimensional array. For ease of understanding, we can think of a two-dimensional array as an array of one-dimensional arrays.
➢ Data in multidimensional arrays are stored in tabular form.
Fig. Tabular Presentation Of 2-D Array
➢Declaration
● General form of declaring N-dimensional arrays:
data_type array_name [size1][size2]....[sizeN];
○ data_type: The data type that will be placed in the array.
○ array_name: Name of the array.
○ size1, size2,... ,sizeN: Dimensions and their sizes.
➢Examples:
○ Two dimensional array:
int two_d[10][20];
○ Three dimensional array:
int three_d[10][20][30];
We can declare a two dimensional integer
array say ‘x’ of size 10,20 as: int x[10][20];
Elements in two-dimensional arrays are commonly referred by x[i][j] where i is the row number and ‘j’ is the column number.
A two – dimensional array can be seen as a table with ‘x’ rows and ‘y’
column
○where the row number is in the range of 0 to (x-1)
○ and column number ranges from 0 to (y-1).
➢Initializing Two – Dimensional Arrays:
A Two-Dimensional array can be initialised in one of two ways.
First Method:
● int x[3][4] = {0, 1 ,2 ,3 ,4 , 5 , 6 , 7
, 8 , 9 , 10 , 11}.
○ There are three rows and four columns in the aforementioned array.
○ In the table, the components in the braces are retained in the same order as they occur in the braces.
○
The array will be filled in order, starting with the first four elements from the left in the first row, followed by the next four elements in the second row, and so on.
Better Method:
●
int x[3][4] = {{0,1,2,3}, {4,5,6,7}, {8,9,10,11}};
○ Nested brackets are used in this type of initialization.
○One row is represented by each set of inner braces.
○Because there are three rows in the previous example, there are three sets of inner braces.
➢Accessing Elements of Two-Dimensional Arrays:
➢Three – dimensional Array (3D-Array)
A three-dimensional array is a more sophisticated version of a multidimensional array. For ease of understanding, a three-dimensional array can be thought of as an array of two-dimensional arrays.
Indirect Method of Declaration:
Declaration – Syntax:
data_type[][][] array_name = new data_type[x][y][z];
For example: int[][][] arr = new int[10][20][30];
Initialization – Syntax:
array_name[array_index][row_index][column_index] = value;
For example: arr[0][0][0] = 1;
Accessing Elements of Three-Dimensional Arrays:
Elements in three-dimensional arrays are commonly referred by x[i][j][k] where ‘i’ is the array number, ‘j’ is the row number and ‘k’ is the column number.
3D array representation in tabular format: A three – dimensional array can be seen as a tables of arrays with ‘x’ rows and ‘y’ columns where the row number ranges from 0 to (x-1) and column number ranges from 0 to (y-1). A three – dimensional array with 3 array containing 3 rows and 3 columns is shown below:
Comparison Between Types Of Arrays in Java
An array is a data structure that allows you to store variables of similar data kinds in close proximity. The array's key benefit is random access and cache friendliness. The array can be divided into three types:
·
One Dimensional
(1D) Array
·
Two Dimension (2D)
Array
· Multidimensional Array
· ➢ One Dimensional Array:
o
It's a collection of variables with comparable data kinds.
o
It allows for random access, and all of the elements can be found by
their index.
o
The array's size is predetermined.
· ➢Two Dimensional Array:
o
It's a collection of lists
of the same data type variable.
o
It also allows for random
access, and all of the elements can be found by their index.
o
It can alternatively be
thought of as a set of 1D arrays. The Matrix is another name for it.
o
Its size can be expanded
from 2 to 3, then 4, and so on.
o
They're all known as
multi-dimensional arrays.
A
2D array is the most common multidimensional array.
o
It's a collection of lists
of the same data type variable.
o
It also allows for random
access, and all of the elements can be found by their index.
o
It can alternatively be
thought of as a set of 1D arrays. The Matrix is another name for it.
o
Its size can be expanded
from 2 to 3, then 4, and so on.
o They're all known as multi-dimensional arrays.
A 2D array is the most common multidimensional array.
Differences On The Basis Of Different Criteria:
o Criteria
One Dimensional
Array
Multidimensional
Array
Definition
Store a single list of the
element of a similar data type as a single dimensional array.
Store a single list of the
element of a similar data type as a two or multidimensional array.
Representation
Represent multiple data items as a
list.
Represent multiple data items as a
table consisting of rows and columns.
Dimension
One
Atleast two or more than two
Size(bytes)
size of(datatype of the variable of
the array) * size of the array
size of(datatype of the variable of
the array)* the number of rows* the number of columns.
Address calculation.
Address of a[index] is equal to (base Address+
Size of each element of array * index).
Address of a[i[[j] can be calculated in two ways
row-major and column-major
Column Major: Base Address + Size of each element
(number of rows(j-lower bound of the column)+(i-lower bound of the rows))
Row Major: Base Address + Size of each element
(number of columns(i-lower bound of the row)+(j-lower bound of the column))
Example
int arr[5]; //an array
with one row and five columns will be created.
{a , b , c , d , e}*
int arr[2][5]; //an
array with two rows and five columns will be created.
a b c d e
f g h i j
|
o Criteria |
One Dimensional
Array |
Multidimensional
Array |
|
Definition |
Store a single list of the
element of a similar data type as a single dimensional array. |
Store a single list of the
element of a similar data type as a two or multidimensional array. |
|
Representation |
Represent multiple data items as a
list. |
Represent multiple data items as a
table consisting of rows and columns. |
|
Dimension |
One |
Atleast two or more than two |
|
Size(bytes) |
size of(datatype of the variable of
the array) * size of the array |
size of(datatype of the variable of
the array)* the number of rows* the number of columns. |
|
Address calculation. |
Address of a[index] is equal to (base Address+
Size of each element of array * index). |
Address of a[i[[j] can be calculated in two ways
row-major and column-major Column Major: Base Address + Size of each element
(number of rows(j-lower bound of the column)+(i-lower bound of the rows)) Row Major: Base Address + Size of each element
(number of columns(i-lower bound of the row)+(j-lower bound of the column)) |
|
Example |
int arr[5]; //an array
with one row and five columns will be created. {a , b , c , d , e}* |
int arr[2][5]; //an
array with two rows and five columns will be created. a b c d e f g h i j |
Real Time Application Of Arrays and Multidimensional Arrays:
o Arrangement of the
leader-board of a game can be done simply through arrays to store the score and
arrange them in descending order to clearly make out the rank of each player in
the game.
o
A straightforward inquiry, The paper consists of a series of numbered
questions, each of which is assigned a score.
o
On a cell phone, there are contacts.
THANKYOU!REFERENCE:1]https://ieeexplore.ieee.org/document/7237077?arnumber=72370772] https://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html3]https://practice.geeksforgeeks.org/4]https://www.javatpoint.com/
o A straightforward inquiry, The paper consists of a series of numbered questions, each of which is assigned a score.
o On a cell phone, there are contacts.
