Because I couldn't find any reading that explains anything more than int(*p)[5]; I decided to ask a question here, that may also be used as a reference in use of other users, because it is a bit confusing I think. What the heck is int*(*asex)[5]; ?

I am self-taught, but also I've never seen it explained in a variety of different courses AND I never used it in practice. Right now, I need a clear explanation of that, because I am creating a C code analyzer for my project. Even though it wasn't directly explained to me, I am used to the language semantics so here is what I think it means:

• int(*a)[5]; Clearly a pointer to an array of 5 ints (pointer to int[5])
• int(**asex)[5]; pointer to an array of 5 int pointers?
• int(*arr[10])[10]; That should be an array of 10 pointers to int[10]
• int*(*asex)[5]; What is that? pointer to a pointer to int[5] ?

What did I got wrong? Additionally, I feel like the only real advantage of this is shown with pointer arithmetic, is that true?

CodePudding user response：

There is a trick to read these definitions: the spiral method.

1. start from the symbol
2. parse the suffix operators left to right ([] for arrays and () for functions), if you reach a ), skip to the next rule
3. then parse the prefix operators right to left, * for pointer to
4. when you reach a ( skip back to step 2 for the parenthesized expression.
5. if you reach the final type stop.

Applying this to the examples:

• int(*a)[5]; defines a pointer to arrays of 5 ints. Typically the type received by a function taking a matrix defined as int mat[4][5];
• int(**asex)[5]; defines a pointer to a pointer to arrays of 5 ints. The type of the address of the function argument defined above.
• int(*arr[10])[10]; defines an array of 10 pointers to arrays of 10 ints. You could store 10 pointers to matrices with 10 columns and various numbers of rows.
• Finally int*(*asex)[5]; defines a pointer to arrays of 5 pointers to int.