Correct Way of Declaring Pointer Variables in C/C++

Correct way of declaring pointer variables in C/C++

Bjarne Stroustrup said:

The choice between "int* p;" and "int *p;" is not about right and wrong, but about style and emphasis. C emphasized expressions; declarations were often considered little more than a necessary evil. C++, on the other hand, has a heavy emphasis on types.

A "typical C programmer" writes "int *p;" and explains it "*p is what is the int" emphasizing syntax, and may point to the C (and C++) declaration grammar to argue for the correctness of the style. Indeed, the * binds to the name p in the grammar.

A "typical C++ programmer" writes "int* p;" and explains it "p is a pointer to an int" emphasizing type. Indeed the type of p is int*. I clearly prefer that emphasis and see it as important for using the more advanced parts of C++ well.

Source: http://www.stroustrup.com/bs_faq2.html#whitespace

I'd recommend the latter style because in the situation where you are declaring multiple pointers in a single line (your 4th example), having the asterisk with the variable will be what you're used to.

Pointer declaration in C, whats the difference?

Grammatically, the type uint8_t is a declaration-specifier; whereas the pointer * is a declarator. According to C's grammar declarators bind to the declared name rather than the declaration-specifier. Consequently your first line is parsed like:

uint8_t (*start_ptr), end_ptr;

i.e. only the first name becomes a pointer.

This is one reason some tend to put the space before the pointer * rather than after. The correct way to declare those in one line would be:

uint8_t *start_ptr, *end_ptr; // both are pointers to uint8_t.

How can I declare a Pointer to a struct in C?

It doesn't matter where you put the spaces. struct Card* p and struct Card *p are equally valid; it's just a matter of style as to which one you prefer.

I agree the second form is more common, but what's most important is that you use one form consistently throughout your code. Your boss / teacher / other developers may also have coding style standards that specify which form to use.

In C, what is the correct syntax for declaring pointers?

It is simply a matter of how you like to read it.

The reason that some people put it like this:

Type *instance;

Is because it says that only instance is a pointer. Because if you have a list of variables:

int* a, b, c;

Only a is a pointer, so it's easier like so

int *a, b, c, *d;

Where both a and d are pointers. It actually makes no difference, it's just about readability.

Other people like having the * next to the type, because (among other reasons) they consider it a "pointer to an integer" and think the * belongs with the type, not the variable.

Personally, I always do

Type *instance;

But it really is up to you, and your company/school code style guidelines.

What is the correct way to declare a pointer to a __far pointer?

I believe you would do this:

unsigned int * __far *VariableThreePtrPtr;

A far pointer to a far pointer would be:

unsigned int * __far * __far VariableFourPtrPtr;

In C, does it matter where I put the * in a pointer variable declaration?

Basically, there's no difference between them.

But I prefer this method:

int *p;

Instead of:

int* p;

or

int * p;

The reason is that because if you want to declare a number of int * in the same line, it makes more sense to have the * next to the identifier instead of the type because that looks cleaner and less confusing. e.g.

int *p, *q, *r;

is better than:

int* p, *q, * r;

If you don't like my reasons, make sure you stick to one of them and don't vary the usage.

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