A 2d array in Java (and many other languages) is just an array of 1d arrays. If you think of it as rows and columns, then each row may have the same number of columns, but that's not necessarily true. You get the number of rows by a.length and the number of columns in the second row, for example, as a.length. That should be enough for you to finish your assignment.
Joined: Jul 07, 2007
Yes, the original thing I got stuck in my mind was that I forgot each row has same number of columns. a.length == a.length so this will work
As picking any row will yield same amount of columns for traditional array. But you also mentioned that each row may have different columns. While I am not quite familiar with that but I think I have heard of it before. I am not sure how to initialize array like that. But I came up with the following code, it might be able to still generate the last value of the 2d array when each row may have different numbers of columns and also if the numbers of columns was not given. I guess this is what I was looking for when I first asked the question.