Question

How can I let a pointer assigned with a two dimensional array?

The following code won’t work.

float a1[2][2] = { {0,1},{2,3}};
float a2[3][2] = { {0,1},{2,3},{4,5}};
float a3[4][2] = { {0,1},{2,3},{4,5},{6,7}};

float** b = (float**)a1;

//float** b = (float**)a2;
//float** b = (float**)a3;

cout << b[0][0] << b[0][1] <<  b[1][0] <<  b[1][1] << endl;

Answer 1

a1 is not convertible to float**. So what you’re doing is illegal, and wouldn’t produce the desired result.

Try this:

float (*b)[2] = a1;
cout << b[0][0] << b[0][1] <<  b[1][0] <<  b[1][1] << endl;

This will work because two dimensional array of type float[M][2] can convert to float (*)[2]. They’re compatible for any value of M.

As a general rule, Type[M][N] can convert to Type (*)[N] for any non-negative integral value of M and N.