public

class Array2Demo {

public static void main(String[] args){

int[][] arr = new int [3][4];

arr[1][2] = 78;

int[][] arr1 = new int[3][];

arr1[0] =new int[3];

arr1[1] = new int[1];

arr1[2] = new int [2];

arr1[0][2] = 90;

arr1[1][0] = 80;

arr1[2][1] = 70;

int[][] arr2 = {{1,2,3,4},{5,6},{7,7},{8,9}};

int sum=0;

for(int x=0; x<arr2.length; x++){

for(int y=0; y<arr2[x].length ; y++){

sum +=arr2[x][y];

}

}

//System.out.println("sum =" + " " + sum);

// System.out.println(arr);

// System.out.println(arr[0]);

// System.out.println(arr[0][0]);

// System.out.println(arr[1][2]);

//

// System.out.println(arr1);

// System.out.println(arr1[0]);

// System.out.println(arr1[0][2]);

// System.out.println(arr1[1][0]);

// System.out.println(arr1[2][1]);

//

// System.out.println(arr2);

// System.out.println(arr2[0]);

// System.out.println(arr2[0][3]);

//

// System.out.println(arr2.length);

// System.out.println(arr2[1].length);

}

}

Array2Demo