CODEWITHSUNDEEP
cpointers
user1758424
user1758424

Reputation: 85

Initializing pointers in C

I see two option to assign a pointer

1.

int p=5;
int *r=&p

2.

int p
int *r;
r=&p;

Why do they use in 1 with asterisk and in two without?

Upvotes: 2

Views: 1808

Answers (5)

Oki Sallata
Oki Sallata

Reputation: 374

because in 1. int *r=&p is declaration.

and in 2. r=&p is not in declaration.

asterix (*) means data type of pointer.

For more information, you can read here

Upvotes: 0

ppeterka
ppeterka

Reputation: 20726

The second is exactly the same. The first example declares the variable and assigns value too in one go. The declaration part needs the *, as that specifies that this variable will store a pointer to an int value. The value assignment part doesn't need this kind of thing, since the variable r is already declared to be a pointer.

Upvotes: 0

Andriy
Andriy

Reputation: 8604

Case 2: int *r is a declaration of an uninitialized pointer to int; r = &p is an assignment which sets the value to the pointer.

Case 1: int *r=&p is a declaration of a pointer to int which is initialized with the address of p.

Upvotes: 0

Mat
Mat

Reputation: 206689

You should read this:

int *r [...]

as:

(int *) r [...]

The type of r is int *. If you look at it that way, you'll see that both versions are identical.

Upvotes: 8

Some programmer dude
Some programmer dude

Reputation: 409166

The two alternatives are actually the same. The first is just less text.

The asterisk, when used in a declaration like int *r, is what tells the compiler that the variable r is a pointer.

Upvotes: 3

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