Win a copy of Re-engineering Legacy Software this week in the Refactoring forum
or Docker in Action in the Agile forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

Multidimensional Arrays

 
Ravi Ahuja
Ranch Hand
Posts: 45
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

[ans]
Hello Everyone
Can Anyone explain me what is the answer of the above program
and why ?
[/ans]
 
Barry Gaunt
Ranch Hand
Posts: 7729
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Please mention the source of any mock exam question that you post.
 
Greg L Tonn
Ranch Hand
Posts: 52
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The only one I know that would work is "B" but I don't know the others.

Could someone give an idea of how to draw/map this out on paper so we could figure it out for ourselves?

Thanks
 
Andy Morris
Ranch Hand
Posts: 78
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The answer is A, B, E and F (correct me if you disagree!)

A: b2[0][1] refers to a 2d array, which b is.
B: b[0][0] refers to a byte value, which b3 is.
E: b2[0][1][0][0] refers to a single byte value, as does b[0][0]
F: b2[0][1] refers to a 2d array, which 'big' is.

C: b2[1][1][0] refers to a 1d array, whereas b[0][0] refers to a single byte
D: b2[1][2][0] refers to a 1d array, whereas b is a 2d array

If you can't just see the number of dimensions when looking at the code you could look at an array like this:

byte b2 [][][][] = new byte [2][3][1][2]; //a 4d array

If you put:
b2[0][1][0][0] you're referring to a single value
b2[0][1][0] you're referring to a 1d array
b2[0][1] you're referring to a 2d array
b2[0] you're referring to a 3d array
b2 you're referring to a 4d array

Notice the pattern - so you could apply this to other arrays:

e.g
byte [][] b = new byte [2][1]; //a 2d array

b[0][0] single value
b[0] 1d array
b 2d array

There might be easier ways of working this out but I think once you're familiar with working with arrays (through practise) it's like doing timestables and the answer is obvious.
[ November 27, 2006: Message edited by: Andy Morris ]
 
Greg L Tonn
Ranch Hand
Posts: 52
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Andy,

So it doesn't matter what the size of the array is only the demensions?
 
Andy Morris
Ranch Hand
Posts: 78
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
For compilation only the dimensions matter.
For runtime the size does matter (you'll get ArrayIndexOutOfBoundsExceptions if you reference an index that is not valid).
 
Nikhil Bansal
Ranch Hand
Posts: 60
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks Andy for your inputs.It really helped.

Regards

Nikhil
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic