Arrays in Java

An array is collection of values of same datatype.Its length is decided when it is created.It has index by which its element are accessed.
Index of array is always from 0 to n-1 ( for n size of array).

• How to declare array?

datatype[ ]  array_name; Example : ( int[] array_name; ) or (float[] array_name;)

• How to allocate memory to array?

array-name = new datatype[size];

 Example( array_name= new int[10];) or (array_name=new float[15]). 

size is number of elements you can store array.

• How you can initialize array?

array_name[0]= value;

array_name[1]=value1;

Example

array_name[0]=1;

array_name[2]=4;

Above example state that '1' value is stored at position 0 and '4' at position 2.

• How to access element of array at some position ?

System.out.println("Elements at position 1"+array_name[1]);

• How to do initialize and declare array in same step?

int array_name[] ={3,70,47,87,34,55};

Program Example in Eclipse

import java.util.Scanner;
public class arrayexp {

public static void main(String[] args) {
int i;
Scanner sc = new Scanner(System.in);
System.out.println("enter how much element u want in array ");
i=sc.nextInt();
int Arry[] = new int[i];
System.out.println("enter element s");
for(int a=0;a Arry[a]=sc.nextInt();
}
System.out.println("Elements in array are ");
for(int a=0;a System.out.print(" "+Arry[a]);
}

}


}

Output

enter how much element u want in array
4
enter element s
2
4
6
8
Elements in array are
 2 4 6 8