C Pointer Declarations

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C/C++ Pointer Declaration Syntax – It makes sense!

I never really liked the way pointers are declared in C/C++:

int *a, *b, *c; // a, b and c are pointers to int

The reason is that I am used to reading variable declarations as MyType myVar1, myVar2, myVar3; and I always read “int*” as the type “integer pointer”�. I therefore wanted the following

int* a, b, c; // a is a pointer to int, b and c are ints

to mean that a, b and c all were of type int*, i.e. pointers to int. and I therefore found it slightly annoying to repeat the asterisk for every variable. This also meant that the symbol * had two slightly different meanings to me: (1) It declares a pointer or (2) it dereferences a pointer. I usually don't declare a whole lot of pointers in one line, but still, this is a (minor) annoyance I have briefly discussed with few fellow programmers over the years. Today I started reading C Traps and Pitfalls by Andrew Koenig and after reading one sentence, in chapter two, the pointer declaration syntax suddenly makes – at least some – sense:

[…] Analogously,

float *pf;

means that *pf is a float and therefore that pf is a pointer to a float.

Of course! If we instead of looking at it as a variable a of type int*, read it as *a – i.e. “a dereferenced” –� it makes sense. That is indeed an int, and that also means that * always means “dereference”�.

Discussion

• http://www.reddit.com/r/programming/comments/pz3n0/cc_pointer_declaration_syntax_it_makes_sense/
• http://news.ycombinator.com/item?id=3615750

Whatever gets you through the day. I personally always need the * next to the variable so there's no mistaken what it is. I also, always try to prefix my pointer variables with "p" so that I know what I'm working with later. It's just a matter of style really. I see it both ways in code and always cringe when it's moved away from the variable.

My problem with attaching it to the variable is twofold: It blends in with pointer dereferences and it doesn't make sense in the function return value scenario:

int *function_call();

The pointer is not to the function, it is to the return value. My preference is to not take sides, I just put spaces on both sides:

int * function_call();
int * a, * b, * c;

@jwmcglynn: the function call is the same. If you dererence function_call(), you get an integer.

@jwmcglynn: ouch... Spaces on both sides? In the case of returning a pointer, I would put the * next to the return type because, clearly, it does not belong next to the function. I've never seen the * next to the function; ever. Spaces on both sides, in my opinion, makes the code less readable. This is all just my opinion. I'm not saying I'm right or an authority on style.

This mode of thought doesn't make a lot of sense (syntactically) with casting.

This is well-defined, you just need to think like a compiler:
http://ieng9.ucsd.edu/~cs30x/rt_lt.rule.html

把优先级记好就可以了