I need to dinamically allocate an two dimensional array in VC++, but i have no idea how to do it. Anyone can help, please ?

As far as I know, that is impossible. One workaround is the following:

char *DynamicArray = NULL;

void main()
{
DynamicArray = new char[x * y];
DynamicArray[x][y] = ''!'';
}

You can do something like that. It will not actually be a 2d array, but you can access it as one. x and y are not variables, just placeholder data to show you the example

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You are not a real programmer until you end all your sentences with semicolons;

Yanroy@usa.com

That won't work. I don't even think that will compile. Since this question keeps coming up, please go read:

http://www.cerfnet.com/~mpcline/c++-faq-lite/freestore-mgmt.html#[16.15]

And read the follow up question if you so desire.

-Brian

Edited by - osmanb on 3/29/00 11:38:04 AM

I also should have mentioned that I'd rather just use a vector of vectors, which makes them resizable:

#include <vector>using namespace std;int main(){ vector<double> TempRow(100); // One row w/100 things vector<vector<double> > Matrix(100,TempRow); // 100 copies of TempRow... now a 100x100 matrix ...}  

-Brian

Edited by - osmanb on 3/29/00 11:37:00 AM

One way to do that is as follows:

char** 2D_Array;

...

for (int i = 0; i < 10; i++)
2D_Array = new char[10];


something like that should work just fine.. haven''t tested that, and haven''t programmed in C/C++ in a few months so I don''t remember exactly if that would compile. (I think it will)

..-=ViKtOr=-..

oppps..

2D_Array = new char[10];

should read

2D_Array = new char[10];

basically the code allocates 10x10 array of chars..

good luck!

..-=ViKtOr=-..

god dammit... i thought i forgot to type it but it seems like the message board removes the brackets

what you need is this... 2D_Array
<br><br>hope this shows up..<br><br>you need rectangular brackets (symbolizing an array) and an "i" between the brackets.. you place that right after 2D_Array on the second line of code.. i hope you understrand what i''ve tried to show you..<br><br>l8r<br><br>..-=ViKtOr=-.. </i>

Gladiator:
You still need to allocate the base indirection layer.

typedef char * pchar;

char ** CharArray = new pchar[X_DIM];
for (int j = 0; j < X_DIM; j++) {
CharArray[j] = new char[Y_DIM];
}

To deallocate:

for (int j = 0; j < X_DIM; j++) {
delete [] (CharArray[j]);
}
delete [] CharArray;

criminy, why all the crazy code. All you need to do is allocate a single dimension array of the size you need for a double dimension array and then index the array using offsets.

I.E.

char* array = new char[x*y];
array[x+y*width] = ''new value here'';

all you actually have to know ahead of time is the width, which can be calculated when you create the array.

The first x is the width, and the y the height.

The second x is the column you want, and the y the row.

Bworks.Com

quote: criminy, why all the crazy code.

Many library routines require that matrices be given to them in standard double-derefernced two-d arrays rather than one-d arrays that use funky indexing. It also aids clarity of code. e.g. array[3][4] makes a lot more sense and looks cleaner than array[3 * 7 + 4].