c - Two dimensional array address and corresponding pointer to its 1st element -

in terms of 1 dimensional array, array name address of first element. fine assign pointer, below:

char data[5]; char* p_data=data; 

so think should same 2 dimensional array. array name should address of first element's address. so, i'd this:

char data[5][5]; char** pp_data=data; 

then warning saying pointer type char** incompatible char[ ][ ].

why happen? comprehend pointer , array concept wrong?

you're right array referred pointer first element. when have "two dimensional" array

char data[5][5]; 

what have array of arrays. first element of array data array of 5 characters. code work:

char (*pa_data)[5] = data; 

here pa_data pointer array. compiler won't complain it, may or may not useful you.

it's true pointer-to-pointer char **pp_data can made act two-dimensional array, have memory allocation work. turns out in array-of-arrays char data[5][5] there's no pointer-to-char pp_data pointer to. (in particular, not pp_data = &data[0][0].)

see this question in c faq list.