Is there a convention for pointer declarations in C? [closed]

Question

When declaring pointers in C, there are 3 variants:

Variant A:

int* ptr; 

Variant B:

int *ptr; 

Variant C:

int * ptr; 

• In A, the indirection operator has been appended to the type.
• In B, the indirection operator has been prepended to the variable.
• In C, the indirection operator stands freely in between type and variable.

The way a pointer is declared differs depending on the type of documentation I read. Some authors seem to have a preference for certain variants, others use several.

• Am I correct to assume that there is no difference in functionality between the different variants?
• If yes, is there a convention for which variant one should be using in C?

Answer 1

Something nobody else has mentioned is that

int *ptr; 

corresponds more closely to the language grammar.

• int *ptr; is a declaration, which consists of:
  • a declaration-specifier int, followed by
  • a declarator, *ptr.

(That actually skips a number of steps, but it gets the basic idea across.)

Since declaration follows use, what this means is that *ptr is of type int. It follows from this that ptr is of type int*.

One could argue that this makes it better than

int* ptr; 

for the same reason that

x = y+z; 

is better than

x=y + z; 

Of course you can write

int* ptr; 

and read it as "ptr is of type int*". And plenty of programmers do exactly that, and get along just fine (it tends to be the preferred style in C++). The compiler doesn't care which way you do it, and anyone reading your code shouldn't have trouble understanding it either way.

But whichever spacing you choose, you need to understand what int *ptr; really means, so that when you see

int *ptr, i; 

in someone else's code (as you inevitably will), you'll immediately understand that ptr is a pointer and i is an int.

And if you're working with other programmers on a project, you should follow whatever existing convention is in the coding standards, or if there isn't one, the way the code is already written. I personally prefer int *ptr; to int* ptr;, but using a mixture of both styles is far worse than using either one consistently.