2-Dimensional array in java.

Two dimensional array is nothing but set of many one dimensional array which are represented in usually rows and columns but they are stored in continuous memory location.The syntax of 2-D array is

int twoD[][] = new int[4][5]; 

It allocates 4x5 int elements in an array which internally stores 80 bytes of memory(If one int takes 4 bytes of memory).

We can also assign the elements to an array dynamically and the syntax goes like this :

int[][] a={{1,2,3},{4,5,6},{8,9,10}};

We can also allocate row with different columns and this type of an array is called as jagged array.

int[][] a={{1,2,3},{5,6},{8,9,10,11}};

Sample code goes here:

import java.util.*;
class arraydemo
{
    public static void main(String args[])
    {
        Scanner scan=new Scanner(System.in);
        int r,c,a[][];
        System.out.println("Enter the number of rows"); 
        r=scan.nextInt(); //Number of rows in an array
        System.out.println("Enter the number of columns");
        c=scan.nextInt(); //number of columns in an array
        a=new int[r][c]; //To initialize two dimensional array
        System.out.println("Enter the elements in an array");
       for(int i=0;i<r;i++)
       {
           for(int j=0;j<c;j++)
           {
               a[i][j]=scan.nextInt(); //To input the elements from an user
           }
       }
       System.out.println("The elements in an array");
       for(int i=0;i<r;i++)
       {
           for(int j=0;j<c;j++)
           {
                System.out.print(a[i][j]+"  "); //Display the elements in a matrix form
           }
           System.out.println("");
       }
    }
}