Multidimensional Array

An multidimensional arrays are arrays of arrays. To declare a multidimensional array (2-D) variable, specify each additional index using another set of square brackets. For example, 
int twoD[ ][ ]  =  new int[4][5];

 This allocates a 4 by 5 array and assigns it to twoD. Internally this matrix is implemented as an array of arrays of int. You require two "for" loops to implement 2-D array.

 PROGRAM 
class TwoDArrayDemo {

 public static void main(String[] args) {
  
  int twoD[][]= new int[4][5];
  
  int i, j, k = 0;
  
  for(i=0; i<4; i++)
   for(j=0; j<5; j++) {
    twoD[i][j] = k;
    k++;
  }
  
  for(i=0; i<4; i++) {
   for(j=0; j<5; j++)
    System.out.print(twoD[i][j] + " ");
   System.out.println();
  }

 }
}
OUTPUT 
C:\>javac TwoDArrayDemo.java
C:\>java TwoDArrayDemo
0 1 2 3 4 
5 6 7 8 9 
10 11 12 13 14 
15 16 17 18 19

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