proably a simple c++ question

[Radical Edward]

I have a book here on c++ which I am trying to follow, but at one point it swaps the

thing.function();

for

thing->function();

what is the difference?

[pablissimo]

I think -> dereferences first. So if 'thing' is a pointer to some object, thing->function() first deferences the pointer to get the object it points to, then called its function() method on it.

For example, from the MSDN site:

   // Declare a new object of type Point.
   Point ptOrigin;

   // Member function calls use the . member-selection operator.
   ptOrigin.SetX( 0 );

cf

   // Declare a pointer to an object of type Point.
   Point *pptCurrent = new Point;

   // Member function calls use the -> member-selection operator.
   pptCurrent->SetX( ptOrigin.GetX() + 10 );

Note the differences between how Point ptOrigin and pptCurrent are defined.

[Radical Edward]

excellent. thanks

[Weeks]

Yeah what pab said.

1) thing.function(arg);
2) thing->function(arg);

'thing' in 2 is a pointer, 'thing' in 1 isn't.

[queball]

thing 2 doesn't even have to be a literal pointer, it could just be something that operator-> is defined for. Often an iterator.