How does passing objects to functions work?

[riptyde]

I've been reading up on c++ a lot lately and I seem to be understanding everything, except this concept. I can't seem to find information anywhere about how passing an object to a function works. I watched this tutorial:

http://www.youtube.com/watch?v=jn3lT07owCo&feature=BFa&list=SPAE85DE8440AA6B83&lf=list_related

as well as its second part and saw it being done, but I can't seem to grasp the concept since it wasn't thoroughly explained in the video.

If someone could clarify how it works I would be greatly appreciative!
Thank you!

[Gaminic]

Haven't watched the video, but you can pass objects to functions just like you would any other variable type:

struct POD {
    int x, y;
    Pod(int X, int Y) : x(X), y(Y) {};
}
int sumXY(POD p) {
  return p.x+p.y;
}
int main() {
  POD myPod(4,5);
  cout << "Value of x + y: " << sumXY(myPod);
  return 0;
}

Just like with basic types, you can pass objects by value (but you generally shouldn't, since copying large objects is expensive), pointer or reference.

[sohguanh]

First, do you know how passing in a primitive type to function work? That is passed in a int,char etc into a function? If yes, then passing in object is similar. The only difference is the object is composed of many primitive/object types internally. Since composed of many primitive/object types it is important for performance not a whole copy of the object is passed in but a reference or a pointer of an object into it.