Thread: How did you master pointers?

Originally Posted by Afrinux

Thanks guys!
I have read salem and xeddiex examples. At first glance, I have to admit it, I havent understand everything yet. But I will make an effort to understand both explanations and when I get stuck again, I will come back to ask questions. Here I understand that a pointer to a pointer has to point to another pointer's address.
If I understand, a pointer can also point to a pointer's address. Then what is the use of pointer to a pointer, if a normal pointer can point to another pointer's address?
Comparing salem's example and xeddiex's example:
A pointer can point to a variable address ( ptr = &addr; ) as well to another pointer address (int *p2p = &p; ).
Will this pointer (int *p2p = &p; ) have the same function as the pointer (int **p2p2 = &p )?
Or did xeddiex mean (int **p2p = &p; )? See how fast I get confused

fgw_three and Mad_guy, thanks again. I will try drawing as well.
Afrinux

Ok, first off, It's normal to be confused, you have to in order to "master" pointers:P. Else you're probably some super geeky weirdo who'd I wouldn't wanna socialize with (just joking).

Like I stated in my first post: The address of a pointer variable (pointers are variables too) is not the same as the address of a non-pointer variable. A pointer with only 1 asterisk can only hold an address (variable, array etc,) that is not a pointer. A pointer with 2 asterisk can only hold an address of a pointer which was declared as as a, pointer (char*).

char **p2p;
char *p = &p2p; // no-no
char *p = p2p; // no-no

char variable;
char *p = &variable; // ok

[BTW: p2p stands for pointer to pointer so don't think I'm declaring it as a normal pointer, which I would declare as, p]


xeddiex.

Originally Posted by xeddiex

Ok, first off, It's normal to be confused, you have to in order to "master" pointers:P. Else you're probably some super geeky weirdo who'd I wouldn't wanna socialize with (just joking).

hahaha! I might be a geek, but I might come out with a code which can make, any dude takes Angelina Jolie or Jennifer Lopez out. I am sure you will be begging to socialize with me (..., now I am dreaming ).
Thanks for the detailled explanation. And also thank you fgw_three.
I tried to have a look at a pointer to a pointer. Well I think it is too early for the challenge. I gotta stick to normal pointers first. And after that, I will give them a re-try.
Afrinux

Originally Posted by Afrinux

Thanks guys!
I Then what is the use of pointer to a pointer, if a normal pointer can point to another pointer's address?

fgw_three and Mad_guy, thanks again. I will try drawing as well.
Afrinux

First off, you're welcome. Along the way I've had many folks who've helped me to learn things, and I've always felt the best way to thank them is to pass knowledge on in like manner.....

This probably won't make much sense to you, but I'm at work and don't have the time to make a proper example, but a pointer to a pointer is useful is you need to pass a pointer by reference into a function.

Suppose you have a function that, among other things, malloc's some memory. If you malloc the memory inside the function, and have associate it with a pointer defined inside that function, the pointer will disappear when the function returns. (The malloc-ed memory won't, and that would be a memory leak, but that's a different story).

So, you pass the ADDRESS of a pointer into your function, and associate the malloc-ed memory with that pointer (that is defined outside your function).

Thus, you need a pointer to a pointer.....

Hope that helps a little....