Two Dimensional Array in Java language

We will get to know about Two Dimensional Array in Java programming language in this tutorial.

In the Java Programming Language, an array is a fixed sequential collection of elements of the same data types. An array can be used to represent a list of numbers(int) or names (string) or other data type of similar elements. It is one of the ways of grouping similar type of data under single- variable name.

Three type of arrays in Java programming language.

1. One dimensional array

2. Two-dimensional array

3. Three-dimensional array

Two-dimensional array in java

Typically, the two-dimensional array is an array data structure and it is one of the types of the multi-dimensional array in the Java programming language. Two dimensional array may contain data types such as int[][] or float[][] or string[][] with two pairs of square brackets. The elements of the two-dimensional array are arranged in rows and columns as follows.

Two Dimension Array in Java language — Two Dimension Array in Java

Declaration

Syntax

Two dimensional Array can be declared as…

data_Type[][] array_name;  ------------ 1  or
data_Type [][]array_name;  ------------ 2 or
data_Type array_name [][];  ------------ 3  or
data_Type []array_name[] ;  ------------ 4

Example

Example for Two dimension Array declaration

int [][]number;

Two Dimension Array in Java language

Creation of two dimension Array

Syntax

data_type array_name=new data_type[row index][column index];

Example

int a=new int[3][4];// 3 row and 4 column

Initiation of two dimension array

We can initiate two-dimensional array in a various way. This method is initiated using one element. we put an element in every cell address.

Method 1

Syntax

array_name[row index][column index]=value;

Example

a[0][0]=45; //initialized first cell address

Example for initiation

array[0][0]=97; //this cell address is array[0][0]

array[0][1]=17; //this cell address is array[0][1]

array[0][2]=27; //this cell address is array[0][2]

array[0][3]=93; //this cell address is array[0][3]

array[1][0]=65; //this cell address is array[1][0]

array[1][1]=87; //this cell address is array[1][1]

array[1][2]=90; //this cell address is array[1][2]

array[1][3]=27; //this cell address is array[1][3]

array[2][0]=45; //this cell address is array[2][0]

array[2][1]=86; //this cell address is array[2][1]

array[2][2]=80; //this cell address is array[2][2]

array[2][3]=77; //this cell address is array[2][3]

Memory representation of above two dimension Array program

Method 2

int[][] marks={ //3 rows 4 coloum

{56,76,95,45}, //row 1

{42,65,37,58}, //row 2

{87,32,64,98}, //row 3

};

The default initial value of 2 – dim array in Java

When we declare an array, memory allocates space to store element and it is assigned to every cell by default initial value 0 for numeric, null for String, false for boolean etc.

We will learn deeply another chapter

class Default_Array{
public static void main(String args[]){
int age[][]=new int[2][3];  //2 d array declaration
for(int i=0; i<=1; i++){
    for(int j=0; j<=2; j++){
        System.out.println(age[i][j]);
                      }
                  }
              }
      }

When the above code is compiled and executed, it will produce the following results

How to display the array elements from the Two-dimensional array in Java

Accessing array elements

Display Array element in the 2d array

System.out.print(Array_name[column index][row index]);

Program 1

class twodarrayex{
public static void main(String args[])
{
int[][]marks; //declaration of array
marks=new int[2][3];//initiation of array
//initiate elements
marks[0][0]=25;
marks[0][1]=15;
marks[0][2]=20;
marks[1][0]=54;
marks[1][1]=10;
marks[1][2]=30;
//Display elements from array
System.out.println(marks[0][0]);
System.out.println(marks[0][1]);
System.out.println(marks[0][2]);
System.out.println(marks[1][0]);
System.out.println(marks[1][1]);
System.out.println(marks[1][2]);
}
}

When the above code is compiled and executed, it will produce the following results

Program

class TwoDarrayex1{
public static void main(String args[]){
int[][] array  =
{ //array declaration and initiation
{63,43,54,32}, 
{45,92,31,27},
{54,71,69,62},
};
//display elements
System.out.println(array[0][0]);
System.out.println(array[0][1]);
System.out.println(array[0][2]);
System.out.println(array[0][3]);
System.out.println(array[1][0]);
System.out.println(array[1][1]);
System.out.println(array[1][2]);
System.out.println(array[1][3]);
System.out.println(array[2][0]);
System.out.println(array[2][1]);
System.out.println(array[2][2]);
System.out.println(array[2][3]);

}
}

When the above code is compiled and executed, it will produce the following results

Program 1

class twodimArray{
public static void main (String args[]){
int[][] anArray;
anArray=new int[2][6];       // array declaration 
// array initiation
anArray[0][0]=124;           
anArray[0][1]=24;
anArray[0][2]=14;
anArray[0][3]=12;
anArray[0][4]=104;
anArray[0][5]=120;
anArray[1][0]=129;
anArray[1][1]=195;
anArray[1][2]=145;
anArray[1][3]=674;
anArray[1][4]=145;
anArray[1][5]=624;

//display array element
System.out.println("Element at index[0][0] :"+anArray[0][0]);
System.out.println("Element at index[0][1] :"+anArray[0][1]);
System.out.println("Element at index[0][2] :"+anArray[0][2]);
System.out.println("Element at index[0][3] :"+anArray[0][3]);
System.out.println("Element at index[0][4] :"+anArray[0][4]);
System.out.println("Element at index[0][5] :"+anArray[0][5]);
System.out.println("Element at index[1][0] :"+anArray[1][0]);
System.out.println("Element at index[1][1] :"+anArray[1][1]);
System.out.println("Element at index[1][2] :"+anArray[1][2]);
System.out.println("Element at index[1][3] :"+anArray[1][3]);
System.out.println("Element at index[1][4] :"+anArray[1][4]);
System.out.println("Element at index[1][5] :"+anArray[1][5]);
}
}

When the above code is compiled and executed, it will produce the following results

Element at index[0][0] : 124
Element at index[0][1] : 24
Element at index[0][2] : 14
Element at index[0][3] : 12
Element at index[0][4] : 104
Element at index[0][5] : 120
Element at index[1][0] : 129
Element at index[1][1] : 195
Element at index[1][2] : 145
Element at index[1][3] : 674
Element at index[1][4] : 145
Element at index[1][5] : 624

Access array elements using for loop in Java

We can print elements of all cells’ address in the two-dimensional array using nested for loop based in the index

for(int i=0; i<=1; i++){
for(int j=0; j<=5; j++){
System.out.println(array_name[i][j]);
}
}

class array2d{
public static void main (String args[]){
int[][] anArray;
anArray=new int[2][6];
anArray[0][0]=345;
anArray[0][1]=145;
anArray[0][2]=365;
anArray[0][3]=349;
anArray[0][4]=355;
anArray[0][5]=745;
anArray[1][0]=340;
anArray[1][1]=315;
anArray[1][2]=445;
anArray[1][3]=344;
anArray[1][4]=375;
anArray[1][5]=645;

for(int i=0; i<=anArray.length-1; i++){
    for(int j=0; j<=anArray.length-1; j++){
    System.out.println(anArray[i][j]);
}
    }
        }

            }

When the above code is compiled and executed, it will produce the following results

Access element in two dimension Array using enhanced for loop

We can print elements of all cells’ address in the two-dimensional array using nested enhanced for loop – based in an index

for(int[]:array_name){
for(int j:i){
System.out.println(j)
}
}

Program 1

class array_2d{
public static void main (String args[]){
int x[][]=new int[3][3];
x[0][0]=305;
x[0][1]=320;
x[0][2]=133;
x[1][0]=355;
x[1][1]=460;
x[1][2]=666;
x[2][0]=365;
x[2][1]=530;
x[2][2]=533;



for(int i[]:x){
    for(int j:i){
    System.out.println(j);
}
}
}

}

When the above code is compiled and executed, it will produce the following results

Access element in two dimension Array using while loop

We can print elements of all cells’ address in the two-dimensional array using nested While loop in Java based on the index

while(i<=1){
while(j<=2){
System.out.println(array_name[i][j]);
}
}

Program 1

class TwoD_array_while{
public static void main(String args[]){
int[][] array;  //array declaration
array=new int[2][3]; //array initiation
array[0][0]=967; //Assign value to array
array[0][1]=157;                
array[0][2]=247;          
array[1][0]=933;         
array[1][1]=625;             
array[1][2]=897;             

int i=0;
while(i<=1){//outer while loop
    int j=0;
    while(j<=2){//inner while loop
    System.out.println(array[i][j]);
    j++;
            }
        i++;
        }
    
    }

}

When the above code is compiled and executed, it will produce the following results