Differences when using ** in C

Question

I started learning C recently, and I\'m having a problem understanding pointer syntax, for example when I write the following line:

int ** arr = NULL;
         


        

Answer 1

How can I know if :

• arr is a pointer to a pointer of an integer

It is always a pointer to pointer to integer.

• arr is a pointer to an array of pointers to integers
• arr is a pointer to an array of pointers to arrays of integers

It can never be that. A pointer to an array of pointers to integers would be declared like this:

int* (*arr)[n]

It sounds as if you have been tricked to use int** by poor teachers/books/tutorials. It is almost always incorrect practice, as explained here and here and ( with detailed explanation about array pointers) here.

EDIT

Finally got around to writing a detailed post explaining what arrays are, what look-up tables are, why the latter are bad and what you should use instead: Correctly allocating multi-dimensional arrays.