reference to self ... so to speak

Im just getting back into C and Im realizing how much I've forgotten (or didn't know)

anyhow I'm trying to do some OOP. And I've got a class, where I want to define a pointer to the same class. That way I can make references to "siblings". Does anyone know what is the way to go about this?

are you talking about the "this" pointer?

wouldn't that be pointing to itself then?

I want to point to the same type but a different instance

essentialy I want to do this

Code:

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class myClass{
   
    myClass *pointer;

}

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So in essence you did it correctly... So what is the problem?

Quote:

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Originally Posted by scorche

essentialy I want to do this

Code:

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class myClass{
   
    myClass *pointer;

}

---

---

It's really just assigning

pointer = this;

But then you could just use "this" directly.

edit:
I think I really must be missing something in the question

Quote:

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Originally Posted by scorche

essentialy I want to do this

Code:

---

class myClass{
   
    myClass *pointer;

}

---

---

Sorry to burst your bubble, but:

Code:

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class myClass
{
    myClass* pointer;
}

---

This is a pointer to the same class type.

Code:

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class myClass
{
    myClass& reference;
}

---

This is a reference to the same class type.

And this is C++, not C (big difference).

he did say both pointer and reference in his post. So its pretty easy to assume he meant pointer here.

I dislike the idea to use the word "reference" to something if you aren't actually using references because C++ sets them apart.
And I wanted to fix that ugly bind-to-the-name style :)

sorry, I've spent the last 2 years sonverting c++ practices to actionscript, and now I'm doing it the other way round...

thanks, I'll give it a go

now I'm getting this error

i switched to

Code:

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class myClass
{
    myClass& reference;
}

---

63 error: structure `_class' with uninitialized reference members

Using a reference is harder than a pointer, because you have to initialize the reference in the constructor's initialization list. (And it also makes copying harder.)

I'd just use a pointer and set it to null if you don't have an address to assign to it when you construct the object.

Elysia kind of has a point about this specific case (though I will argue with her about passing things by pointer/reference at times). You could make a reference....

Example:

Code:

---

class MyBaseClass
{
private:
  int x, y;

public:
  MyBaseClass() : x(0), y(0) { }
  virtual ~MyBaseClass() { }

  virtual void doSomething() = 0;

  int getX() const { return x; }
  int getY() const { return y; }
  void setX(int X) { x = X; }
  void setY(int Y) { y = Y; }
};

class MyOther : public MyBaseClass
{
protected:
  MyBaseClass &ref;

public:
  MyOther(MyBaseClass &Ref) : ref(Ref) { }
  virtual ~MyOther() { }

  virtual void doSomething() { /* whatever */ }
};

---

Anyway, not the best example but you see the difference.

references have to be initialized when the reference is declared... probably not the best choice here as both the siblings would need to be instantiated together (and I can't really imagine a good way to do that)

"So in essence you did it correctly... So what is the problem?"

I don't know... it gave me an error :)
but I think it's ok now, must have done something silly...

I guess that's why I get an error when I'm creating the class

Fair enough. I do silly things all the time.

now I get an error here :

Code:

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myVector[myClass.size-1]._reference_tomyClass = & myVector[myClass.size];

---

I think I did it right ... but maybe I missed something


***** EDIT

I'm anitiot ...

I missed the ()

thanks everyone for your help

Could you provide more code and the exact error message? It makes it easier to help diagnose the problem.

anitiot is a good word :) I was reading it as Ani-tiot. Which is clearly not the intent

Can I recommend that you avoid using the word "reference" for pointers and vice versa?
In C++, a pointer to something is NOT a reference to something.
You can create confusion. But regardless if don't, it's just good practice to name your variables correctly.

right... 'cause they're 2 different things

except i'm pointing to a class that I'm refrencing it to. so I'm calling it a reference not because it is a c++ reference, but because in the use of it, I use it as because refrence-relation to another class, but then I didn't need to have it in the examples..

I will make a compromise with you, Elysia. I will always call a reference (&) a reference on the C++ board, and a pointer (*) a pointer on the C++ board. But on the C board I am allowed to call a pointer parameter (*) a reference.

By the way:

Quote:

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Originally Posted by urbandictionary

"anitiot isn't defined yet."

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Quote:

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Originally Posted by master5001

IBut on the C board I am allowed to call a pointer parameter (*) a reference.

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I will disagree.
A pointer is not a reference, even if it's C.
But of course, I'm not allowed to dictate what you are allowed to do and what you are not.

Well I do try to be respectful of other competent members. I suppose this may be an issue of newfangled teaching techniques that are floating around these days. I can agree with you to an extent, but in C and assembler a pointer is the only way to pass by reference. If anything, I would make stronger argumets for a reference to be renamed to something else. But there is no more appropriate moniker than "reference." So without introducing circular logic the point is moot. I do appreciate your concern over use of the appropriate descriptions though. It is beneficial to those who are learning. But a lot of books will also tend to say something is being passed by reference (when you would say "pointer").

If anything, I can re-negotiate the compromise to for C I will use the term "passing by address" which I think even you can conceed is accurate and unambiguous. But using such terms runs the risk of people not knowing what I mean.

Quote:

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Originally Posted by master5001

...but in C and assembler a pointer is the only way to pass by reference...

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No, you can only pass by pointer.
Simple.

Quote:

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If anything, I can re-negotiate the compromise to for C I will use the term "passing by address" which I think even you can conceed is accurate and unambiguous. But using such terms runs the risk of people not knowing what I mean.

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Usually, from what I've seen or remembered, I don't think it matters that much if you pointer, address or reference.
And if they don't know, then it is a simple matter of educating them.

But I stand firm to my own beliefs that you can not pass by reference in C, only by pointer. The end.
I am grateful that you are trying to respect this, though.

>> I suppose this may be an issue of newfangled teaching techniques that are floating around these days. <<

I think this might just be Elysia's personal preference. I know I've never heard anybody else complain about referring to a pointer as referencing another object.

As long as people are aware that in C++ the term "reference" has a specific well-defined meaning beyond the normal programming term, then I don't think its wrong to use both in the proper context.

It's like the terms string or map. There is a C++ string and a C++ map, but that doesn't mean that a sequence of characters can't also be called a string and it doesn't mean you can't map one object to another with something other than a std::map.

>> No, you can only pass by pointer. Simple. <<

Not so simple. Pass-by-reference is a well defined programming term. You can't just stop using it because the word reference is used elsewhere.

Quote:

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Originally Posted by Elysia

No, you can only pass by pointer.
Simple.

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"Pass by reference" is a parameter passing method in the literature. It can be implemented via pointers, C++ references, etc.

Yeah we will have to agree to disagree. Though I guess I agree with you almost asymptotically. I mean there is only a very small amount of disagreement on the issue. I can certainly say its one of those things I will have to shrug off because it doesn't matter. I just hate needing to "choose my words carefully." However look at the silver lining, I will just say what I am going to say and by doing so you are guaranteed a boost in post count ;)

Quote:

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Originally Posted by laserlight

"Pass by reference" is a parameter passing method in the literature. It can be implemented via pointers, C++ references, etc.

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You are my official best friend of the day. Thank you laserlight.

Quote:

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Originally Posted by laserlight

"Pass by reference" is a parameter passing method in the literature. It can be implemented via pointers, C++ references, etc.

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I realize it may have further meanings and can indeed mean both things, but I will have to disagree.
In C, you can only pass by pointer. It's etched into the language.

Also, if you're talking programming languages, it's better to use programming-language specific words over more general ones.
If I say, you should store a reference to that and that, it might imply, in C++, that you should actually store a reference, and not a pointer.

So long story short, it's pass by pointer or nothing in my book, though not necessarily anyone else's.

I concur with the majority opinion. C++ provides two ways to "pass by reference". Blame Stroustrup for calling one of them "reference" to confuse the issue.

In C references (&) do not exist. Which I am well aware that you know. Bleh... laserlight, just close the thread.

Quote:

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Originally Posted by Elysia

In C, you can only pass by pointer. It's etched into the language.

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No, in C, you can only pass by value.

Quote:

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Originally Posted by Elysia

Also, if you're talking programming languages, it's better to use programming-language specific words over more general ones.

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The phrase is in the programming language literature.

Thanks for the correction.
Anyway, this is pointless. No more arguments from me.

Likewise. No hostility or arguments here. I just hate to see stuff drag out aimlessly. This is what happens when beginners aren't posting fun to answer questions :P

Quote:

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This is what happens when beginners aren't posting fun to answer questions :P

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Go check the C forum ;)