quick question

[Amon Ra]

probably a stupid one:
if in VB code i encounter AddressOf, what would i replace it with in C++? just omit it? or use & ?
thanks

[crptcblade]

I believe & is the AddressOf operator, yes.

[Amon Ra]

what about Me?
thanks

[filburt1]

Originally posted by crptcblade
I believe & is the AddressOf operator, yes.

If you pass a variable to a function and it does not need to be modified, here's a trick that saves memory:

int foo(const int &i)

You reference i just as normal, but since you don't need to modify it you pass a constant reference pointer instead of a whole new copy of the object/variable.

[jim mcnamara]

VB Me = VC++ this

ie., use this

Is not completely the same, but good enuff.

[kedaman]

Originally posted by crptcblade
I believe & is the AddressOf operator, yes.

AddressOf in vb is only used to retrieve the address of a function. the function name addresses the function in C++

& in C++ is used to retrieve the address of a variable, equivalent to varptr in vb.

[Amon Ra]

so isn't "this" used in classes?
then if i can use it outside classes, i can use it replace "Me" right?
thanks

[CornedBee]

this is a POINTER, and it is used to pass the class object you are in as parameter or return value.
For example, the MFC CRect has a function named UpperLeft() that returns a changable reference to a CPoint that represents the upper left point of the rectangle:

// CRect is derived from windows RECT, so it has left, top, right and bottom as members, in this order.
// CPoint is derived from windows POINT, so it has x and y as members, in this order.

// return a CPoint object through which the upper left edge of the rect can be changed
inline CPoint & CRect::UpperLeft()
{
    return *((CPoint*)(this));
}

// for the lower right point:
inline CPoint & CRect::LowerRight()
{
    return *(((CPoint*)this)+1);
}

RECT:
LONG left, top, right, bottom;

POINT:
LONG x, y;

This is a cool way to use the this-pointer.

There is another:

class B;

class A
{
public:
  A(B* b);
  B* parent;
}

class B
{
public:
  B();
  A embedded;
}

A::A(B* b)
{
  parent = b;
}

B::B()
 : embedded(this)  // constructor list: the clean way to construct an embedded object
{
}

The A class requires a B pointer in it's constructor. To get one, you need the this pointer in the B constructor.

[Amon Ra]

okok, but what if i use "this" outside of a class? ok, i am trying to understand the ssubtimer from vbaccelerator, but i cant figure out what the me has to do when calling lets say AttachMessage..

AttachMessage Me, Me.hwnd, WM_SIZE

[CornedBee]

I don't know about Me in VB (what it does exactly).
If you use "this" outside a class, you'll get this error:
error C2673: '(function name)': global functions don't have a this-pointer
As always, this is a translation from german...

If you use the Me in a module attached to a form, al functions probably are member functions of the form class. This could be why Me works "outside" classes.

[Amon Ra]

ok, so might the Me some sort of a pointer(i know there aren't any in VB) to the window class or something? i really need to find an equivalent..
thanks =)

[abdul]

"Me" is no way related to "this" in a class.
VB has just made this object to simplify the code a bit. So, for example, you don't need to write the name of the form. You can just write "Me" instead.

[abdul]

Originally posted by Amon Ra
ok, so might the Me some sort of a pointer(i know there aren't any in VB) to the window class or something? i really need to find an equivalent..
thanks =)

"Me" is just used in vb. You need to use the handle of the window to work with its properties.
And you always use API to do that because there is no object in C++ (like form,timer,commandbutton,etc in vb).

[jim mcnamara]

anything in C that references the firaty element of a vector is in itself a pointer

char *t;
char tmp[80];
  t = tmp;             << is legal

[CornedBee]

uuhhh. jim, what has this got to do with the thread? Nothing personal, just wondering...