Getting the length of two-dimensional array

Question

How do I get the second dimension of an array if I don't know it? array.length gives only the first dimension.

For example, in

public class B {     public static void main(String [] main){         int [] [] nir = new int [2] [3];         System.out.println(nir.length);     } } 

how would I get the value of the second dimension of nir, which is 3.

Thanks

Answer 1

which 3?

You've created a multi-dimentional array. nir is an array of int arrays; you've got two arrays of length three.

System.out.println(nir[0].length);  

would give you the length of your first array.

Also worth noting is that you don't have to initialize a multi-dimensional array as you did, which means all the arrays don't have to be the same length (or exist at all).

int nir[][] = new int[5][]; nir[0] = new int[5]; nir[1] = new int[3]; System.out.println(nir[0].length); // 5 System.out.println(nir[1].length); // 3 System.out.println(nir[2].length); // Null pointer exception 

Answer 2

In the latest version of JAVA this is how you do it:

nir.length //is the first dimension nir[0].length //is the second dimension