C++ lists usage

Question

In Java there is a collection called ArrayList. It allows programmer to add an object of type T and remove them by issuing a simple methods, like

list.remove(object);
list.add(object);

For C++ I've found that standard vectors are using value objects only, so I dont see the way to achieve same functionality. The case is that I want to hold a reference to an object elsewhere why being able remove or add it using some composition pattern. What I'm asking for is how to achieve something like this in C++:

class Composite {

  ArrayList<Composite> children = new ArrayList<>();

  public void addChild(Composite child) {
    children.add(child);
  }


  public void removeChild(Composite child) {
    children.remove(child)
  }
}


class Test{
  public static void main() {
    Composite a = new Composite();
    Composite b = new Composite();
    a.addChild(b);
    a.removeChild(b);

    // from here on a.children is empty.        
  }

} 

I dont even know how to bite this thing in C++. Thanks.

UPDATE: Thanks to the ResidenBiscuit answer and others comments I was able to figure out the basic code for this, which is available at this pastebin url: http://pastebin.com/h17hh3r4

Answer 1

In Java, everything besides POD is a reference. There's no specifying you want a reference, because that's all you get.

Not so much in C++. Everything defaults to value. If you want a std::list of reference types, then you'll need a compiler supporting C++11 std::reference_wrapper. You can then do:

std::list<std::reference_wrapper<Type>> t_list

To add to this list, you would need to use std::ref:

t_list.push_back(std::ref(myObj))

Now everything you add into this list will just be a std::reference_wrapper type. You could also store pointers instead by just doing:

std::list<Type*> tptr_list

Which may be easier, or the only option if you don't have a C++11 compliant compiler.