Array in Java

Introduction of Array In Java


Array is used to store similar type of elements. 

Array declaration :

For one dimensional

datatype arrayname[]=new datatype[size];

or

datatype arrayname[]={val1,val2.....valn};

For Two dimensional

datatype arrayname[][]=new datatype[rows][cols];

or

datatype arrayname[][]={
                       {val1,val2.....valn},
                       {val1,val2.....valn},
                       {val1,val2.....valn}
                       
                     };

Note

1. To check size of array

   Syntex :
   arrayname.length
   

2. To check size of individual row of array

   Syntex :
   arrayname[row-number].length
   

Save this file ArrayDemo.java

public class ArrayDemo
{
	public static void main(String args[])
	{
		int a[] = {34,345,6,89,76,34,34,56,78,89,56,23,23,45,34};
		int b[][] = 	{
							{1,2,3,4},
							{5,6,7,8}
						};
		int i, j; 
			
			
		System.out.println("Contents of A....");
		for (i=0;i<a.length;i++)
			System.out.println(a[i]);
			
			
		System.out.println("Contents of B....");
		for (i=0;i<b.length;i++)			
		{
			System.out.println();
			for (j=0;j<b[i].length;j++)	
				System.out.print(b[i][j] + "   ");
		}
		
		System.out.println();	
	}
}

Save this file ArrayDemo.java


import java.io.*;

public class ArrayDemo
{
	public static void main(String args[])
	{
		int num[][], i, j;
		num = new int[5][8];
		
		System.out.println(num.length);
		
		for (i=0;i<num.length;i++)
		{
			System.out.println("num[" + i + "] is an array with " + num[i].length + " elements");
		}
		
		Console console = System.console();
		for (i=0;i<num.length;i++)
		{
			System.out.println("Reading row #" + i + "....");
			for (j=0;j<num[i].length;j++)
			{
				System.out.print("Enter value #" + j + " : ");
				num[i][j] = Integer.parseInt(console.readLine());
			}
		}
		
		System.out.println("You entered the following values....");
		for (i=0;i<num.length;i++)
		{
			System.out.println();
			for (j=0;j<"num[i].length";j++)
				System.out.print(num[i][j] + "       ");
		}
	}
}