Length of each Row

The length of a 2D array is the number of rows it has. The row index runs from 0 to length-1.

Each row of a 2D array can have a different number of elements, so each row has its own length:

class unevenExample3
{
  public static void main( String[] arg )
  {
    // declare and construct a 2D array
    int[][] uneven = 
        { { 1, 9, 4 },
          { 0, 2},
          { 0, 1, 2, 3, 4 } };

    // length of the array (number of rows)
    System.out.println("Length of array is: " + uneven.length );

    // length of each row (number of its columns)
    System.out.println("Length of row[0] is: " + uneven[0].length );
    System.out.println("Length of row[1] is: " + uneven[1].length );
    System.out.println("Length of row[2] is: " + uneven[2].length );
  }
}

Notice that uneven[0] refers to row 0 of the array, uneven[1] refers to row 1, and so on.