Passing pointer to 2D array c++

Question

I'm having this problem for quite a long time - I have fixed sized 2D array as a class member.

class myClass
{ 
public:
        void getpointeM(...??????...);
        double * retpointM();

private:

   double M[3][3];

};

int main()
{
     myClass moo;
     double *A[3][3];

     moo.getpointM( A );  ???
     A = moo.retpointM(); ???

} 

I'd like to pass pointer to M matrix outside. It's probably very simple, but I just can't find the proper combination of & and * etc.

Thanks for help.

Answer 1

double *A[3][3]; is a 2-dimensional array of double *s. You want double (*A)[3][3]; .

Then, note that A and *A and **A all have the same address, just different types.

Making a typedef can simplify things:

typedef double d3x3[3][3];

This being C++, you should pass the variable by reference, not pointer:

void getpointeM( d3x3 &matrix );

Now you don't need to use parens in type names, and the compiler makes sure you're passing an array of the correct size.