Question

how to pass the input through 2d array argument in java

Answer 1

you can use two 'for loops' to take the input in a 2d array. Basically we can visualize a 2d array as an simple array in which all the individual elements are themselves an array. So the first 'for' loop will is used for traversing the main array index while the 2nd 'for' loop is used to input the elements in the inner array at a particular index.

0	1	2	3	4	5	6	7
a1	b1	c1	d1	e1	f1	g1	h1
a2	b2	c2	d2	e2	f2	g2	h2
a3	b3	c3	d3	e3	f3	g3	h3
a4	b4	c4	d4	e4	f4	g4	h4

 for(int i=0 ; i<n1 ; i++){                           // n1 is the no. of arrays in the main array\

for(int j=0 ; j<n2;j++){                             // n2 is the no. of elements in the subsequent arrays

arr[i][j] = sc.nextInt();

}}

Answer 2

I've put together a small code where one can pass 2d arrays as arguments to functions. This demonstrates that we pass arguments by reference as loadIdentity changes the array:

public class Main
{
    public static void loadIdentity(int[][] array)
    {
        for (int row = 0; row < array.length; row++)
        {
            for (int column = 0; column < array[row].length; column++)
            {
                array[row][column] = row == column ? 1 : 0;
            }
        }
    }
    
    public static void print(int[][] array)
    {
        for (int row = 0; row < array.length; row++)
        {
            for (int column = 0; column < array[row].length; column++)
            {
                System.out.print(array[row][column] + " ");
            }
            System.out.println();
        }
    }
    
    public static void main(String[] args)
    {
        int[][] array = {{1, 2}, {3, 4}};

        System.out.println("Original array:");
        print(array);

        System.out.println();
        System.out.println("Identity array:");
        loadIdentity(array);
        print(array);
    }
}