Move Semantics and Perfect Forwarding in C++11

//COPY ELISION

#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>


//#define MOVE_FUNCTIONALITY

int count_copies = 0;
int count_allocations = 0;
int elem_access = 0;

class Array
{
    int m_size;  
    double *m_array;    
public:
    Array():m_size(0),m_array(nullptr) {}
    Array(int n):m_size(n),m_array(new double[n])
    {
        std::cout << ">>>allocate:" << n << std::endl;
        count_allocations += n;        
    }

    Array(const Array& x):m_size(x.m_size),m_array(new double[m_size])
    {
        std::cout << ">>>(const Array& x) copy:" << m_size << std::endl;
        count_allocations += m_size;
        count_copies += m_size;        
        std::copy(x.m_array, x.m_array+x.m_size, m_array); 
    }

#ifdef MOVE_FUNCTIONALITY
    Array(Array&& x):m_size(x.m_size),m_array(x.m_array)
    {    
        std::cout << ">>>(Array&&) move" << std::endl;
        x.m_size = 0;       // clearing the contents of x
        x.m_array = nullptr;        
    }
#endif

    virtual ~Array()
    { 
        std::cout << ">>>delete: " << m_size << std::endl;
        delete [] m_array;
    }


    auto Swap(Array& y) -> void
    {        
        std::cout << ">>>swap" << std::endl;
        int n = m_size;
        double* v = m_array;
        m_size = y.m_size;
        m_array = y.m_array;
        y.m_size = n;
        y.m_array = v;
    }

#ifdef MOVE_FUNCTIONALITY
    auto operator=(Array&& x) -> Array&
    { 
        Swap(x);
        return *this;
    }
#endif

    auto operator=(const Array& x) -> Array&
    {                
        if (x.m_size == m_size)
        {
            std::cout << ">>>copy assignment:" << m_size << std::endl;
            count_copies += m_size;            
            std::copy(x.m_array, x.m_array+x.m_size, m_array);
        }
        else
        {
            Array y(x);
            Swap(y);
        }
        return *this;        
    }


    auto operator[](int i) -> double&
    {
        elem_access++;
        return m_array[i];
    }

    auto operator[](int i) const -> double
    {
        elem_access++;
        return m_array[i];
    }

    auto size() const ->int { return m_size;}

#ifdef MOVE_FUNCTIONALITY

    template<class T>
    friend auto operator+(T&& x, const Array& y) -> Array
    {      
        int n = x.m_size;        
        Array z(std::forward<T>(x));
        for (int i = 0; i < n; ++i)
        {
            elem_access+=2;
            z.m_array[i] += y.m_array[i];
        }        
        return z;
    }

    template<class T>
    friend auto operator+(T&& x, Array&& y) -> Array
    {        
        return std::move(y)+x;        
    }
#else
    friend auto operator+(const Array& x, const Array& y) -> Array
    {                
        int n = x.m_size;
        Array z(n);        
        for (int i = 0; i < n; ++i)
        { 
            elem_access += 3;
            z.m_array[i] = x.m_array[i] + y.m_array[i];
        }        
        return z;
    }          
#endif

    void print(const std::string& title) const
    {
        std::cout << title;
        for (int i = 0; i < m_size; ++i)
        {
            elem_access++;
            std::cout << " " << m_array[i];
        };     
        std::cout << std::endl;         
    }
};

const Array f()
{
    Array z(2);
    z[0] = 2.1;
    z[1] = 33.2;
    return z;
}

Array f1()
{
    Array z(2);
    z[0] = 2.1;
    z[1] = 33.2;
    return z;
}

void g(Array&& a)
{    
    a.print("g(Array&&)");
}

void g(const Array& a)
{    
    a.print("g(const Array&)");
}

void pf(Array a)
{    
    a.print("pf(Array)");
}

int main()
{
    {
        Array p(f());
        p.print("p");
        g(f());
        g(f1());
        pf(f());        
    }
    std::cout << "total allocations (elements):" << count_allocations << std::endl;
    int total_elem_access = count_copies*2 + elem_access;
    std::cout << "total elem access (elements):" << total_elem_access << std::endl;
    return 0;          
}