Thread: Class acessing caller?

Ok, I have a class function:

Code:

//Just an example
class Pointless {
 private:
  int x;
 public:
  Pointless();
  int GetX() {return x;}

  Pointless ReturnSelf();
};

Pointless Pointless::ReturnSelf() {
 return Self;
}

Thats an example, I know I could inline ReturnSelf to :P.

So, I just want to return whatever called ReturnSelf. Like:

Code:

int main() {
 Pointless a;
 Pointless *b;

 b = &a.ReturnSelf(); // Is this even valid expression? -,-.

Once again, thats an example :P. But it would be the eqivalent of:

Code:

int main() {
 Pointless a;
 Pointless *b;

 b = &a;
}

Thank you for your help!

[edit]
Miswrote my example... -,-.

Copy constructor.

www.google.com

If that isn't what you're looking for, then maybe someone else will get your question better.

Umm...? What do I copy when I dont know the name of what I'm attempting to copy...

Code:

class Pointless {
 private:
  int x;
 public:
  Pointless();
  int GetX() {return x;}
  Pointless(const Pointless &p) {x=p.GetX();}

  Pointless ReturnSelf();
};

Pointless Pointless::ReturnSelf() {
 return Self;
}

What? Once again, I'm trying to get the object that called it.

Code:

Pointless a;
Pointless *b;

b = &a.ReturnSelf();

=

Code:

Pointless a;
Pointless *b;

b = &a;

You're trying to copy a into b. What do you mean you don't know what you're attempting to copy?

Code:

#include <iostream>

class Foo {
   public:
     Foo(int);           // The constructor
     Foo(const Foo&);    // The copy constructor
     ~Foo();
     
     int x;
};

Foo::Foo(int num) : x(num) {}
Foo::Foo(const Foo& foo) { x = foo.x; }
Foo::~Foo() {}
    
int main() {
    Foo One(5);       // Calls the constructor
    Foo Two(One);     // Calls the copy constructor
    
    std::cout << Two.x;
    std::cin.get();

    return 0;

}

How are you referring to the object calling the function there?

I dunno, maybe this would do what you are trying, but I haven't compiled to double check.

Code:

&Pointless Pointless::ReturnSelf() {
 return &this;
}

Code:

int main() {
 Pointless a;
 Pointless *b;

 b = a.ReturnSelf();

As Quantum stated:

the this keyword should return the caller that you are attempting to do.

------------------------------------------------------------------------------------------
This section is if you are trying to make a copy, which I am unsure if this is what your intention ultimately is. So you can ignore this part if it doesn't help you.

Note in your example:

Code:

int main() {
 Pointless a;
 Pointless *b;

 b = &a.ReturnSelf(); // Is this even valid expression? -,-.

If this code works, which it might if you replace Self with the this pointer it still won't make a copy of a and store it in b, rather it just makes b point to a. So any changes to one will also be made to the other. b & a are now essentially one object b a.k.a. a.

If you want a true copy you need a copy constructor like someone else mentioned.

Code:

// Note this is a public funtion in Pointless Class.

void Pointless::Operator=(Pointless pIn)
{
   this.x = pIn.x;
}

Code:

int main()
{
Pointless a, b;
b = a;
}

Something like this. Look up overloading the = operator or just use the word copy instead like:

Code:

// Note this is a public funtion in Pointless Class.

void Pointless::copy(Pointless pIn)
{
   this.x = pIn.x;
}

Code:

int main()
{
Pointless a, b;
b.copy(a);
}

P.S. Some of my code may not compile correctly, but the principles should be correct.

Hope some, if any, of this helped.
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By the way, how do you guys have signatures on your posts? I didn't see a sig. option anywhere. Is it because I haven't posted enough yet?

Oh, very nice. I've never seen that keyword. I suppose you can give that a try.

Ah thank you, I was trying to find out how to get at "this". Thanks .

Originally Posted by Blackroot

Ah thank you, I was trying to find out how to get at "this". Thanks .

Why, though? What's wrong with &?