Programming Forums > Application Development > C++

DaWei · Apr 30th, 2006, 8:20 AM

'*' is not "the address of". '&' is "the address of" (in one of its guises). '*' is the opposite (the thangy residing at the address).

Darkhack · Apr 30th, 2006, 10:26 AM

Quote:

Originally Posted by DaWei

'*' is not "the address of". '&' is "the address of" (in one of its guises). '*' is the opposite (the thangy residing at the address).

Ooops!!! DaWei is 100% correct. I'm an idiot. This is why I only have PHP and C# listed as my languages in my profile. Let me try this one more time..

(Toggle Plain Text)

var x = My House
var *y = &x;
print x;   //prints My House
print y;   //prints 0x010000
print *y;  //prints My House

& is read as "the address of"
* is read as "contents of the address"

There are also "pointers to pointers" with **. But I won't go into that on the basis that I might screw up again. :o

Twilight · Apr 30th, 2006, 10:34 PM

Quote:

Originally Posted by grumpy

Arrays are not pointers. In some contexts, in C and C++, pointers and arrays can be treated as if they are equivalent. In reality, however, they are very different things.

That is incorrect. It is easier to work with advanced data structures if you understand pointers. It is, however, possible to do advanced work with data structures with no pointer in sight. Some of the earliest advanced work on data structures (including implementation of linked lists and binary trees) was implemented using programming languages that did not even support anything like a pointer. The only issue is that, if pointers are not used, the bookkeeping techniques to identify (in a linked list) the next node are different. Given that people tend to misuse pointers quite regularly it is often true that, in practice, linked lists implemented without pointers are actually more robust because the programmer does better bookkeeping.

Yeah, I had a feeling I was gonna get called on the array thing, since it doesn't end up as a pointer when you convert it to assembly. But it's almost a pointer :p

However, I had no idea you could do LL's and BST's without pointers. Is it only other languages that can do that, or C++ too?

lectricpharaoh · Apr 30th, 2006, 10:47 PM

Quote:

Originally Posted by Twilight

Yeah, I had a feeling I was gonna get called on the array thing, since it doesn't end up as a pointer when you convert it to assembly. But it's almost a pointer :p

However, I had no idea you could do LL's and BST's without pointers. Is it only other languages that can do that, or C++ too?

You can do it in pretty much any language, though if the language in question doesn't support user-defined types (structs, classes, or something roughly equivalent), it's much messier.

As to how to do it, it's simple: instead of using actual pointers, you allocate an array, and then store indices into the array. Of course, you still have issues regarding the need to resize the array, but even some languages that don't directly support pointers have facilities to do this.

DaWei · Apr 30th, 2006, 10:49 PM

Quote:

Yeah, I had a feeling I was gonna get called on the array thing, since it doesn't end up as a pointer when you convert it to assembly.

Non-sequitur, has nothing to do with it.

OopSheMishtamesh · May 5th, 2006, 7:13 PM

Quote:

Originally Posted by DaWei

Non-sequitur, has nothing to do with it.

couldn't agree more !

OpenLoop · May 5th, 2006, 7:43 PM

I've read a couple of posts about how no one will pay you if you program without classes or pointer. That's a false statement and my paycheck proves it

Let's remember, C is a great language with many applications in embedded and linux, yet it doesn't have classes.
COBOL is good for business applications and data manipulation, yet it doesn't have pointers

mohamad_atef · May 7th, 2006, 12:11 PM

pointers are so important and we can't do without them.

Soulstorm · May 7th, 2006, 1:57 PM

Quote:

Originally Posted by hervens48

Hey people.
Ive read so many tutorials about pointers, but i simply cant get them.
I understand their syntax and everything, but i cant understand what their really for. To me, their just simple intengers.
So is it possible to write a really really large program without using pointers or classes?

Although you can write most programs without the use of pointers, They will tend to be larger in size than otherwise.

Alsom without pointers, you can't proceed into understanding polymorphism in C++.

Although errors with pointers will give you the creeps at first, it is an essential part of C++ programming. And do not forget that the only reason that a thing like this exists, is to facilitate the work of programmmers, and not make it more difficult than it already is. So, as you understand, you will become more efficient if you use pointers and references.

Finally, without pointers, you will really have no luck if you intend to proceed into learning Objective-C (not that you said that you intend to, but just saying...

)

Everyone sees it as a difficult part of C++ at first, and that is proved by the numbers of tutorials and threads on pointers on the internet. But don't let that intimidate you...

DaWei · May 7th, 2006, 4:00 PM

There's a Pointer Basics link in my sig and Narue has a good one, too.

Apr 30th, 2006, 8:20 AM	#11
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	'' is not "the address of". '&' is "the address of" (in one of its guises). '' is the opposite (the thangy residing at the address). __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

May 7th, 2006, 4:00 PM	#20
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	There's a Pointer Basics link in my sig and Narue has a good one, too. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

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May 5th, 2006, 7:43 PM	#17
OpenLoop Expert Programmer Join Date: May 2005 Location: East Lansing, MI Posts: 663 Rep Power: 4	I've read a couple of posts about how no one will pay you if you program without classes or pointer. That's a false statement and my paycheck proves it Let's remember, C is a great language with many applications in embedded and linux, yet it doesn't have classes. COBOL is good for business applications and data manipulation, yet it doesn't have pointers

May 7th, 2006, 12:11 PM	#18
mohamad_atef Newbie Join Date: May 2006 Posts: 1 Rep Power: 0	pointers are so important and we can't do without them.

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Programming Forums > Application Development > C++

Can you program without pointers?