CODEWITHSUNDEEP
javaarraysfor-loop
emma
emma

Reputation: 47

Value of array with two dimensions

Can you please help me understand what the following code means and what the value of number[2][2] is?

public static void main(String[] args) {
    int[][] numbers = new int [3][3];

    for (int i = 0; i < numbers.length; i++) {
        for (int j = 0; j < numbers[0].length; j++) {
            numbers[i][j] = i*j;
        }

Upvotes: 0

Views: 48

Answers (1)

Md Shafayet Maruf
Md Shafayet Maruf

Reputation: 46

In Java, a multiple dimension array is constructed with multiple one dimensional arrays. In your example numbers[3][3] will look like the below array:

numbers = [
     [0, 0, 0],
     [0, 1, 2],
     [0, 2, 4]
]

Now when you ask what will be the length of numbers[0]? Then it is easy to say 3. numbers[0] holds [0, 0, 0]. And if you ask what is the value of numbers[2][2] then it is 4 ( since array index starts with 0 ).

Now here I put another example.

public class Array {
    public static void main(String[] args) {
        int[][] numbers = new int[3][];
        numbers[0] = new int[2];
        numbers[1] = new int[3];
        numbers[2] = new int[4];

        for (int i = 0; i < numbers.length; i++) {
            for (int j = 0; j < numbers[i].length; j++) {
                numbers[i][j] = j;
            }
        }

        for (int i = 0; i < numbers.length; i++) {
            for (int j = 0; j < numbers[i].length; j++) {
                System.out.print(numbers[i][j] + " ");
            }
            System.out.println();
        }
    }
}

Here I take an array and make the internal array size differently. This array will look like this:

numbers = [
     [0, 1],
     [0, 1, 2],
     [0, 1, 2, 3]
]

Here I create the first array with size 2, second array with size 3 and third array with size 4, put some data into it and simply print it.

I think you may now visualize what numbers[0].length actually means.

Upvotes: 1

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