int x[][] = {{1, 2}, {3, 4}};
Since arrays are objects and 2-dimensional arrays are arrays of arrays, then how many objects are in this little piece of code?
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How many are they in your opinion and why do you think like that ?Joe2013– Joe20132013-04-03 10:14:21 +00:00Commented Apr 3, 2013 at 10:14
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I want to say either 2 or 3, but I wasn't sure if maybe the whole thing could be considered 1 object.Kacy Raye– Kacy Raye2013-04-03 10:14:21 +00:00Commented Apr 3, 2013 at 10:14
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Refer here stackoverflow.com/questions/5892905/…Joe2013– Joe20132013-04-03 10:16:14 +00:00Commented Apr 3, 2013 at 10:16
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@Joe2013 - This question is substantially different to that one. This one is about multi-dimensional arrays.Stephen C– Stephen C2013-04-03 12:20:13 +00:00Commented Apr 3, 2013 at 12:20
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2 Answers
Three. One for the top level array of int[] objects, and two int[] objects.
The elements (the integers themselves) are not objects.
My criterion for being "an object" is something that has java.lang.Object as a direct or indirect supertype. All array types are implicitly subtypes of Object, but int is a primitive data type ... and not a subtype of Object.
The other thing to note is that int[][] means "array of int[]" ... in a very literal sense. The int[] objects that you find in an int[][] are real, first-class objects. Your declaration
int[][] x = {{1,2}, {3,4}};
is a short-hand for this:
int[][] x = new int[2][]();
x[0] = new int[]{1, 2};
x[1] = new int[]{3, 4};
4 Comments
Kacy Raye
Thank you. I was leaning towards 3, but I wanted to be sure. And thanks for not being condescending or giving my question a negative vote. I read an entire chapter on arrays and googled for an answer to this question and since it was not explicitly stated anywhere I resorted to stackoverflow. I didn't think it was a dumb question, but some people gave it negative votes.
Neil
And of course
x[0] = new int[]{1, 2}; (which you seem to have typoed as )) is itself shorthand.
Stephen C
@Neil - Thanks. Right on both counts. However, I don't need to drill down through the 2nd level of short-hand to make the point I am trying to make.
Neil
Indeed, you only needed to show all of the objects.
You can adopt three point of views:
- There are four
intvalues in your 2-dimentional array. - You can also see a single 1-dimentional array containing two 1-dimentional arrays, each containing two values.
- A third point of view, centered on
intvsarraysis exposed by Stephen C in his answer, which makes three arrays and fourintvalues and is actually the second-one rephrased differently (so 3 POVs)
