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
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.
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
int [][]number;
Syntax
data_type array_name=new data_type[row index][column index];
Example
int a=new int[3][4];// 3 row and 4 column
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
0 0 0 0 0 0
How to display the array elements from the Two-dimensional array in Java
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
25 15 20 54 10 30
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
63 43 54 32 45 92 31 27 54 71 69 62
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
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
345 145 365 349 355 745 340 315 445 344 375 645
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
305 320 133 355 420 666 365 530 533
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
967 157 247 933 625 897
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