Jagged Array in Java

Prerequisite : Arrays in Java

Jagged array is array of arrays such that member arrays can be of different sizes, i.e., we can create a 2-D arrays but with variable number of columns in each row. These type of arrays are also known as Jagged arrays.

Following are Java programs to demonstrate the above concept.

// Program to demonstrate 2-D jagged array in Java
class Main
{
    public static void main(String[] args)
    {
        // Declaring 2-D array with 2 rows
        int arr[][] = new int[2][];

        // Making the above array Jagged

        // First row has 3 columns
        arr[0] = new int[3];

        // Second row has 2 columns
        arr[1] = new int[2];

        // Initializing array
        int count = 0;
        for (int i=0; i<arr.length; i++)
            for(int j=0; j<arr[i].length; j++)
                arr[i][j] = count++;

        // Displaying the values of 2D Jagged array
        System.out.println("Contents of 2D Jagged Array");
        for (int i=0; i<arr.length; i++)
        {
            for (int j=0; j<arr[i].length; j++)
                System.out.print(arr[i][j] + " ");
            System.out.println();
        }
    }
}

Output:

Contents of 2D Jagged Array
0 1 2 
3 4

Following is another example where i’th row has i columns, i.e., first row has 1 element, second row has two elements and so on.

// Another Java program to demonstrate 2-D jagged 
// array such that first row has 1 element, second
// row has two elements and so on.
class Main
{
    public static void main(String[] args)
    {
        int r = 5;

        // Declaring 2-D array with 5 rows
        int arr[][] = new int[r][];

        // Creating a 2D array such that first row
        // has 1 element, second row has two 
        // elements and so on.
        for (int i=0; i<arr.length; i++)
            arr[i] = new int[i+1];

        // Initializing array
        int count = 0;
        for (int i=0; i<arr.length; i++)
            for(int j=0; j<arr[i].length; j++)
                arr[i][j] = count++;

        // Displaying the values of 2D Jagged array
        System.out.println("Contents of 2D Jagged Array");
        for (int i=0; i<arr.length; i++)
        {
            for (int j=0; j<arr[i].length; j++)
                System.out.print(arr[i][j] + " ");
            System.out.println();
        }
    }
}

Output:

Contents of 2D Jagged Array
0 
1 2 
3 4 5 
6 7 8 9 
10 11 12 13 14 

This article is contributed by Rahul Agrawal. If you like GeeksforGeeks and would like to contribute, you can also write an article and mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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