Arrays

 Arrays

An array represents a group of elements of same data type.We can represents  several elements in a single array

Three types of array

1. One dimensional array

2. Two dimensional array

One dimensional array:-

Syntax:-

dataType[] arr;

(or)  

dataType []arr;

(or)  

dataType arr[];

Instantiation of an Array in Java:-

arrayname=new datatype[size];  

Example:-

class Test{  

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;  

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

System.out.println(a[i]);  

}}  

Output:-10 20 70 40 50

Declaration, Instantiation and Initialization of Java Array:-

Syntax:-
int a[]={33,3,4,5}; //declaration, instantiation and initialization  

Example:

class Test

{  

public static void main(String args[]){  

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

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

System.out.println(a[i]);  

}}  

Output:-

33

3

4

5

Two dimensional array:-

Syntax:-

dataType[][] arrayRefVar; 

(or)  

dataType [][]arrayRefVar; 

(or)  

dataType arrayRefVar[][]; 

(or)  

dataType []arrayRefVar[];  

Example:-

class Test{  
public static void main(String args[]){  
int arr[][]={{1,2,3},{2,4,5},{4,4,5}};  
for(int i=0;i<3;i++){  
 for(int j=0;j<3;j++){  
   System.out.print(a4 4 5rr[i][j]+" ");  
 }  
 System.out.println();  
}  
}} 
Output:-
1 2 3
2 4 5