Multidimensional Array c++

Question

Possible Duplicate:
Multi-dimensional array in C++

I need to create a function that has one parameter which is a multi-dimensional array with two dimensions being user-specified, e.g.

    int function(int a, int b, int array[a][b])
    {
     ...

    }

How would I do that in C++ ?

Your old question should be reopened shortly. – Pubby Jan 17 '12 at 22:14 — Pubby, Jan 17 '12 at 22:14

Neil · Answer 1 · 2012-01-17T22:36:38.943

2

You can do something like this with a template:

template <int A, int B>
int function(int array[A][B])
{
 ...
}

Note that this generates a block of code for each size of array that you use. You can optimise slightly by passing in the outer dimension as a function parameter instead of a template parameter (you can't change the inner dimension because you can't have an array of an array of unknown size).

EDIT: As pointed out on the duplicate bug, I got my template array syntax wrong.

edited Jan 17 '12 at 22:36

answered Jan 17 '12 at 22:15

Neil

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This doesn't fulfill the "user-specified" part, as `A` and `B` should be specified at compile time. – Tamer Shlash Jan 17 '12 at 22:28
1

@Mr.TAMER Depends on your definition of user, I guess - I was assuming he meant caller. – Neil Jan 17 '12 at 22:34

shift66 · Answer 2 · 2012-01-17T22:27:54.123

0

You have to pass size with parameters.
int function(int a, int b, int array[][])
There is no length() method or a method like that in C++. If you pass an array, it's just a link to that. This is the same as int function(int a, int b, int** array)
EDIT:
Note that if you use square braces, not asterisks, you have to give size of all dimensions except the first one. Actually you're passing array of arrays and compiler must know size of each of them.

edited Jan 17 '12 at 22:27

answered Jan 17 '12 at 22:13

shift66

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I tried that but it gave me that eror: declaration of ‘function’ as multidimensional array must have bounds for all dimensions except the first – Gonenc Jan 17 '12 at 22:16
Try with int**.It is reference to your matrix an should work. Wait, Ill edit my answer. – shift66 Jan 17 '12 at 22:18
1

No, this won't work. A two-dimensional array of `int` can't decay to `int**`. – R. Martinho Fernandes Jan 17 '12 at 22:27

Multidimensional Array c++

2 Answers2