Question

I’m currently coding on a project and I have a function that looks like this:

Room::addItem(Item*&); //not written by me

I have some trouble understanding what to send as parameter.. the “*&” mess it up for me.

I’ve tried the following:

foo.addItem(loadItem());         //Returns an Item-object
/*and*/
foo.addItem(loadItem());         //Returns an Item-pointer

edit: It would be nice if you explain what the “*&” means. I want to understand it next time I run in to it 😉

Answer 1

The addItem function accepts argument of type Item* and the pointer is passed by reference. It means that the function addItem can modify the pointer internally. This may also imply that the object is being reallocated or modified inside this function.

Example:

void pointerByValue(int* ptr)
{
   ptr = new int[10];
}


void pointerByReference(int*& ptr)
{
  ptr = new int[10];
}

void main()
{
   int* p = NULL; //A NULL pointer

   pointerByValue(p); //p is still NULL

   pointerByReference(p); //memory has now been allocated to p
}

Pointer By Reference are only valid in C++.