About Question enthuware.ocajp.i.v7.2.938 :

[admin]

You need to understand that length and dimensions are two different things. Sq Brackets denote dimensions while the number inside the bracket is the length of that dimension. I would suggest you to go through any basic tutorial on arrays before attempting these questions.
HTH,
Paul.

[Roibeard]

Ok, thank you.

[flex567]

Does [] have the lowest operator precedence?
And () the highest?

[admin]

Not really. Check this out: https://introcs.cs.princeton.edu/java/11precedence/

[daveyj]

I have gone through this question enthuware.ocajp.i.v8.2.938 and the comments, and I still couldn't get why ia.length is 4, after looking through books and online I'm just not getting it so I decided to write a program to display everything about a multi-dimensional array and it seems to only back up what I thought. Obviously your questions is correct, so can someone please tell me what I am missing? In my program the result of ia.length is 3 yet the only thing that has 3 is the declaration [][][]

class Test{
public static void main(String[] args){
String ia[][][] = { // ia has length 3 as it has 3 multi-dimensional arrays
{ // array ia[0] length 2, it has 2 arrays
{"1a","2a","3a","4a","5a","6a","7a"}, // array [0][0] length is 7, it has 7 elements
{"1b","2b","3b","4b","5b","6b","7b"} // array [0][1] length is 7, it has 7 elements
},
{ // array ia[1] length 4, it has 4 arrays
{"1c","2c","3c","4c","5c"}, // array [1][0] length is 5, it has 5 elements
{"1d","2d","3d","4d","5d"}, // array [1][1] length is 5, it has 5 elements
{"1e","2e","3e","4e","5e"}, // array [1][2] length is 5, it has 5 elements
{"1f","2f","3f","4f","5f"} // array [1][3] length is 5, it has 5 elements
},
{ //array is[2] length 2, it has 2 arrays
{"1g","2g"}, //array [2][0] length is 2, it has 2 elements
{"1h","2h"} //array [2][1] length is 2, it has 2 elements
}
};
System.out.println("ia.length = " + ia.length);
System.out.println("ia[0].length = " + ia[0].length);
System.out.println("ia[1].length = " + ia[1].length);
System.out.println("ia[2].length = " +ia[2].length);
System.out.println("ia[0][0].length = " + ia[0][0].length+", ia[0][1].length = "+ ia[0][1].length);
System.out.println("ia[1][0].length = " + ia[1][0].length+", ia[1][1].length = "+ ia[1][1].length+", ia[1][2].length = "+ ia[1][2].length);
System.out.println("ia[2][0].length = " + ia[2][0].length+", ia[2][1].length = "+ ia[2][1].length);
System.out.println( ia[0][0][0] + ia[0][0][1] + ia[0][0][5] + ia[0][0][6]);
System.out.println( ia[0][1][0] + ia[0][1][1] + ia[0][1][5] + ia[0][1][6]);
System.out.println( ia[1][0][0] + ia[0][0][1] + ia[1][0][3] + ia[0][0][4]);
System.out.println( ia[1][1][0] + ia[1][1][1] + ia[1][1][3] + ia[1][1][4]);
System.out.println( ia[1][2][0] + ia[1][2][1] + ia[1][2][3] + ia[1][2][4]);
System.out.println( ia[1][3][0] + ia[1][3][1] + ia[1][3][3] + ia[1][3][4]);
System.out.println( ia[2][0][0] + ia[2][0][1]);
System.out.println( ia[2][1][0] + ia[2][1][1]);
}
}

Results :
ia.length = 3
ia[0].length = 2
ia[1].length = 4
ia[2].length = 2
ia[0][0].length = 7, ia[0][1].length = 7
ia[1][0].length = 5, ia[1][1].length = 5, ia[1][2].length = 5
ia[2][0].length = 2, ia[2][1].length = 2
1a2a6a7a
1b2b6b7b
1c2a4c5a
1d2d4d5d
1e2e4e5e
1f2f4f5f
1g2g
1h2h

[admin]

Your code is different from the one given in the question. You are missing the line var i = 4;

[daveyj]

Hi admin,

Thank you for your reply. I know mine is different, I wasn't trying to replicate it exactly, but just to map out all the elements. What I don't understand is in my code ia.length is 3 which to my understanding is due to the face that it is a 3 dimensional array and the 3 arrays within it are of different lengths, 2, 4 & 2 as below, which is confirmed by the results of running my code.

Results :
ia.length = 3
ia[0].length = 2
ia[1].length = 4
ia[2].length = 2

But then the question is throwing me because I was expecting ia.length to be 3, regardless of what the value of i is equal to, my thinking is that ia.length should always be 3 because there are 3 [][][] and that it doesn't relate to the value of i. Obviously this is not the case but that seems to be what my code is showing, and I can't understand why.

Any help with understanding this would be greatly appreciated, my exam is scheduled for next week and I want to get my head around this before then.

[admin]

Dimensions is not the same as number of elements! Just because it is a three dimensional array doesn't mean its length is three. By that logic, do you think a two dimensional array will have only two elements and a one dimensional array will have only 1 element?
int[] a = {1, 2, 3, 4}. Here, a.length is 4, not 1!