Question

I have to create a 3-Dimensional array, wich gets allocated at object creation. I’ve done such stuff before with normal arrays.

typedef unsigned char byte;  // =|
byte ***data;

Answer 1

If you’re using C++, I strongly advise you using std::vector instead of raw arrays.

Something like:

std::vector<std::vector<std::vector<char> > > data(3, std::vector<std::vector<char> >(3, std::vector<char>(3, 0)));

Will create a 3x3x3 array of chars, all initialized to 0.

You can then access the items the same way you would with a char***:

data[0][0][0] = 1;

---

Depending on your needs you might also use only one std::vector and inline your three-dimensional space into it. This would fasten both computation and copy operations, as the values would then be in a contiguous block of memory.

The way you could inline the values depending on your needs, but here is an example:

For a 3 dimensional array like this:

a----b
|\   |\
| d----c
e-|--f |
 \|   \|
  h----g

You might store values like this in memory:

a, b, c, d, e, f, g, h

This require some maths, but if you encapsulate this, you can even achieve the same level of usability of a vector of vector of vector, with much higher performances.