/**
 * compile and run with these commands:
 *
 * g++ -std=c++11 -fno-elide-constructors test-move.cpp
 * ./a.outmain()
 *
 * will output the following:

fn()
construct
move
move assignment
delete. (data size = 0)
move
move assignment
delete. (data size = 0)
1
2
3
4
5
delete. (data size = 5)

 *
 **/

#include <iostream>
#include <vector>

using namespace std;

class Object
{
  public:
    Object()
    {
        clog << "construct\n";
        // using initializer list:
        _data = {1,2,3,4,5};
    }

    Object(Object& obj)
    : _data(obj._data)
    {
        clog << "copy\n";
    }

    Object& operator=(Object& obj)
    {
        clog << "copy assignment\n";
        _data = obj._data;
        return *this;
    }

    Object(Object&& obj)
    {
        clog << "move\n";
        // this passes obj along to
        // the move assignment operator
        *this = move(obj);
    }

    Object& operator=(Object&& obj)
    {
        clog << "move assignment\n";
        // all member variables must be
        // move individually
        _data = move(obj._data);
        return *this;
    }

   ~Object()
    {
        // delete. If _data.size() == 0,
        // we are merely deleting a reference
        // and no deallocation is taking place
        clog << "delete."
             << " (data size = "
             << _data.size()
             << ")\n";
    }

    vector<double> _data;
};

Object fn()
{
    clog << "fn()\n";
    Object obj;
    return obj;
}

int main()
{
    clog << "main()\n";

    Object obj = fn();

    // range-based for-loop and the auto keyword
    for (auto x : obj._data)
    {
        cout << x << endl;
    }
}