Correct way to use an array to access multiple arrays of different length in C++

Question

I have several two dimensional arrays of various, differing lengths:

int Array_A[][2] = {{...}, {...}, {...}, ...};
int Array_B[][2] = {{...}, {...}, ...};
int Array_C[][2] = {{...}, ...};

I need another array which allows me to access these arrays:

??? Full_Array[] = {Array_A, Array_B, Array_C};

What is the correct type of ??? that I should use? I tried uint** and uint* but neither works.

If it's not doable, suppose I am not allowed to change the definition of Array_A, Array_B, ... What is a good way to define Full_Array?

Answer 1

Array_A, Array_B, and Array_C are all arrays of arrays of 2 ints, so they can all undergo the array-to-pointer conversion at the top level into pointer to array of 2 ints.

So Full_Array needs to be an array of pointers to arrays of 2 ints. The declaration can be written:

int (*FullArray[])[2] = {Array_A, Array_B, Array_C};

Note that there is no way to tell what the lengths of the subarrays are, unless you have sentinel values.

Answer 2

If the arrays Array_A, Array_B, and Array_C are of the same size, you can create pointers to them using the & operator and store them in an array. If they are of different sizes, the & operator will create different pointer types and you won't be able to store them in the pointer array.

int Array_A[3][2] = { ... };
int Array_B[3][2] = { ... };
int Array_C[3][2] = { ... };

typedef int (*PtrType)[3][2];
PtrType Full_Array[] = {&Array_A, &Array_B, &Array_C};

The following will be an error.

int Array_A[][2] = { {}, {}, {} }; // Implied dimensions [3][2]
int Array_B[][2] = { {}, {} };     // Implied dimensions [2][2]
int Array_C[][2] = { {}, {}, {} }; // Implied dimensions [3][2]

typedef int (*PtrType)[3][2];
PtrType Full_Array[] = {&Array_A, &Array_B, &Array_C};