Re: returning three dimensional array

•

What is DaniWeb IT Discussion Community?

You're currently browsing the C section within the Software Development category of DaniWeb, a massive community of 373,495 software developers, web developers, Internet marketers, and tech gurus who are all enthusiastic about making contacts, networking, and learning from each other. In fact, there are 3,887 IT professionals currently interacting right now! Registration is free, only takes a minute and lets you enjoy all of the interactive features of the site.

Join our community!

Please support our C advertiser:

returning three dimensional array

•

Join Date: Oct 2007

Location: Cherry Hill, NJ

Posts: 1,733

Reputation: Duoas is a name known to all

Rep Power: 9

Solved Threads: 172

Duoas

Offline

Posting Virtuoso

Re: returning three dimensional array

Nov 2nd, 2007

I'm sure you are getting a perfectly fine return value. Your problem is that you have not supplied any type information that the compiler can use to "know" about your array.

First, please see the Wikipedia here.

Next, please be aware that only the first dimension can be [] in C, and only when you are not actually creating data. Other dimensions must have a size. So
int Mat[][][];
is an error, as is
int Mat [][10][5];
but
void printarray( int a[][10][5], int depth );
is not.

However, int *Mat; knows nothing about how many dimensions the array has, or even if it really is an array.

If your array has variable size dimensions, then you should use a simple flat array (or pointer) and calculate things on your own:

Help with Code Tags

(Toggle Plain Text)

int *index_2d_array( int *arr, int height, int width, int y, int x ) {
  int index = (y * width) + x;
  return &(arr[ index ]);
  }

// two differently sized arrays with a "center" element
int a[5][5] = {
  { 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0 },
  { 0, 0, 7, 0, 0 },
  { 0, 0, 0, 0, 0 },
  { 0, 0, 0, 0, 0 }
  };
int b[3][5] = {
  { 0, 0, 0, 0, 0 },
  { 0, 0, 4, 0, 0 },
  { 0, 0, 0, 0, 0 }
  }
// a[3][4] = b[1][3]
*index_2d_array( a,   5, 5,   3, 4 ) = *index_2d_array( b,   3, 5,   1, 3 );

If your Mat object is a variable-sized array, you should create a small library of functions to handle it, and place all relevant information in a structure. For example:

Help with Code Tags

(Toggle Plain Text)

typedef struct {
  int *data;
  int width, height, depth;
  } Mat_t;

int *Mat_element( Mat_t Mat, int z, int y, int x );

Hope this helps.

DaniWeb Home > Forums > Software Development > C > returning three...

Re: returning three dimensional array

returning three dimensional array

Re: returning three dimensional array