What does this symbol mean: ->

as in:

something->new

thanks and happy new year!

thanks

For C....

If you have a structure called mystruct with a member called var, you would access var with mystruct.var.

If you had a pointer to the structure, you would use mystruct->var

Buy a good book about C, for example "The C Programming Language" and learn some C, or read some reference.

klausi

Code:

---

struct FOO
{
    char *stuff = "floobie";
};

int main(void)
{
    struct FOO foo;
    struct FOO *pFoo;

    puts(foo.stuff); /*This will work, prints floobie*/
    puts(pFoo->stuff); /*okay here too, prints floobie*/

    puts(foo->stuff);
    /*bzzzzt, wrong answer!
    **foo is a direct instance, not a pointer
    **-> is used to with a pointer to a struct
    */
    puts(pFoo.stuff);
    /*bzzzzt, also wrong!
    **pFoo is a pointer, treat it like one
    ** the . operator is used for a direct instance only
    */

    return EXIT_SUCCESS;
}

---

-Prelude

I'll make it even easier to understand:

some_struct->element is exactly the same as saying (*some_struct).element

But who wants to dereference a struct just to access its elements? It is a shortcut, like i++ or x |= 7.

a helpful aspect of this deferencing is that passing a pointer to a user defined conglomerate type as an argument to a function is a lot less expensive on the stack than passing the whole instance of the type...

I had been wondering the same thing. Thanks for the answer.
master5001 I have never seen x | = 7 before. What does the |= do?

x |= 7

It's like saying x = x | 7

the | symbol is the bitwsie OR.

It basically works like this...let's say you have two numbers, 2 and 1

0000000010 (binary 2)
0000000001 (binary 1)

well when you bitwise OR them, it comes out like this:

Code:

---

0000000010
          | (OR)
 0000000001
---------------------
 0000000011

---

which is 3

see what it did? Every there was a 1 in a place that there wasn't one in the other number, it put a 1 there. You can basically think of it as adding or combining numbers in binary (but only think of it like that in binary terms, because 6 | 6 != 12, that 2 | 1 = 3 is just sorta a conincidence.

thanks Ken
That is easy enough to understand.

It means "go through".

So if you have a pointer to and structure named 'bunnywabbit'. You can "go through" it (called indirection) to access it's fields.

[code]
typedef struct
{
int ears;
int feet;
int whiskers;
int tail;
}wabbit;


wabbit *bunnywabbit;

bunnywabbit = (wabbit*)malloc(sizeof(wabbit));

bunnywabbit->ears = 2;
bunnywabbit->feet = 4;
bunnywabbit->whiskers = 6;
bunnywabbit->tail = 1;

[\code]

enjoy.

Try code tag the other way (forgive my sorry old head)--

Code:

---


typedef struct
  {
  int ears;
  int feet;
  int whiskers;
  int tail;
  }wabbit;


wabbit *bunnywabbit;

bunnywabbit = (wabbit*)malloc(sizeof(wabbit));

bunnywabbit->ears = 2;
bunnywabbit->feet = 4;
bunnywabbit->whiskers = 6;
bunnywabbit->tail = 1;

---

enjoy.