Question

I need to create a sort of 2D array in which each one of the secondary arrays are of different length. I have a 1D array of known length (which defines the number of arrays to be formed) with each element having a number that denotes the length of the secondary array in that position.

Each one of the arrays are fairly large so i don’t want to create a one-size-fits-all “fake” 2D heap array to cover everything.

How would i go about doing this? Any 2D array I have made before are always rectangular.

I’m trying to do this so that i can create some code to dynamically generate threads to split up some workload.

Thanks,

-Faken

Answer 1

You can do something like following :

int **array = new int*[3];
array[0] = new int[5];
array[1] = new int[2];
array[2] = new int[11];

Do not forget to deallocate properly after you are done with using array.

EDIT :

You can put secondary pointer initialization in the loop in the following way :

int cells[] = {5,2,11};
int **array = new int*[3];
for (int i = 0; i < 3; i++){
  array[i] = new int[cells[i]];
}

PS : I personally prefer to use Boost.MultiArray when I need multidimensional arrays. You might also want to have a look at it.