Java: Swap two rows of 3-dimensional array

Question

I have this array:

int[][][] D = new int[N][M][2];

My question is: how can I swap D[N][M][0] and D[N][M][1] (it is NOT swap two elements, but swap whole array). It maybe seems silly, but I cannot imagine how 3-dimensional array organize, so I don't know which is the best method to copy it. Moreover, I don't sure does D[N][M][0] and D[N][M][1] is two block consecutive in memory ? If not, so I should do that:

int[][][] D = new int[2][N][M]

right ?

Thanks :)

As written D[N][M][0] is an int element, not an array. So you are asking to swap two ints, I believe. — BlackVegetable
– BlackVegetable, Commented Jan 12, 2013 at 19:18
@BlackVegetable No.I have noted that copy whole array, not single element. But I don't really know how to write it clearly. Can you fix my post ? — hqt
– hqt, Commented Jan 12, 2013 at 19:19
As Aleksander Gralak answered, you want to omit the last [0] as it indicates a particular index of that final array. You want D[A][B] to be switched not an element within D[A][B]. — BlackVegetable
– BlackVegetable, Commented Jan 12, 2013 at 19:20
No you do not have to copy one by one. Look at my answer. Each element in multidimensional array is just a reference to the array which is one dimension smaller. At the end when you have only one dimension, then you have real values. — Aleksander Gralak
– Aleksander Gralak, Commented Jan 12, 2013 at 19:22
@AleksanderGralak I think you confused me with another poster. I never proposed switching one by one. In fact, I agree with you. — BlackVegetable
– BlackVegetable, Commented Jan 12, 2013 at 19:23

Charles Menguy · Accepted Answer · 2013-01-12 19:22:09Z

1

D[N][M][0] is just a single int. The whole row is under this reference D[N][M], so to swap rows do this:

int[] tmp = D[N][M];
D[N][M] = D[N][M+1];
D[N][M+1] = tmp;

edited Jan 12, 2013 at 19:22

Charles Menguy

41.6k18 gold badges97 silver badges117 bronze badges

answered Jan 12, 2013 at 19:17

Aleksander Gralak

1,51910 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

BlackVegetable Over a year ago

Just make sure that M+1 is not out of the bounds of the array. (+1)

Collectives™ on Stack Overflow

Java: Swap two rows of 3-dimensional array

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related