我对一段c++程序的理解，望大家指教

#include <stdio.h>
#include <iostream.h>
//using namespace std;


class Point
{
public:
    Point()
    {
        m_x = 0;
        m_y = 0;
        cout<<"construct: x = "<<m_x<<" y = "<<m_y<<endl;
    }

    Point(unsigned int x, unsigned int y)
    {
        m_x = x;
        m_y = y;
        cout<<"construct: x = "<<m_x<<" y = "<<m_y<<endl;
    }

    void print()
    {
        cout<<"x = "<<m_x<<endl;
        cout<<"y = "<<m_y<<endl;
        cout<<endl;
    }

    Point(const Point& p):m_x(p.m_x),m_y(p.m_y){

        cout<<"copy construcor of this from p:(m_x="<<p.m_x<<",m_y="<<p.m_y<<")"<<endl;
    }
    
    ~Point(){
        cout<<"~Point():x="<<m_x<<"y="<<m_y<<endl;

    }

    friend Point operator+(Point& pt, int nOffset);
    friend Point operator+(int nOffset, Point& pt);
public:
    unsigned int m_x;
    unsigned int m_y;
};

Point operator+(Point& pt, int nOffset)
{
    
    //Point temp=pt;//等同于Point temp(pt);初始化是调用拷贝构造函数滴。

    Point temp;
    temp = pt;//调用赋值操作符

    temp.m_x += nOffset;
    temp.m_y += nOffset;
    printf("where\n");
    return temp;
}




int main(int argc, char* argv[])
{
    Point pt(10, 20);

    cout<<"+++++++++++++++++++++"<<endl;
    Point& ptt= pt+3; //这里加不加&（即Point ptt= pt+3似乎没影响），似乎结果都一样，这里有点不明白，请大家指教

    ptt.print();

    cout<<"+++++++++++++++++++++"<<endl;
    pt=pt+4;
    pt.print();

    cout<<"+++++++++++++++++++++"<<endl;
    pt = pt + 1;
    
    getchar();
    return 0;
}

/*

通过对程序3进行单步调试发现：运行结果如下
我的理解如下：有什么不妥的地方，请多多指教

construct: x = 10 y = 20 //pt构造
+++++++++++++++++++++
construct: x = 0 y = 0 //temp构造
where
copy construcor of this from p:(m_x=13,m_y=23) //生成临时对象
~Point():x=13y=23            //析构temp
x = 13
y = 23

+++++++++++++++++++++
construct: x = 0 y = 0 //temp构造
where
copy construcor of this from p:(m_x=14,m_y=24) //生成临时对象
~Point():x=14y=24 //析构temp
~Point():x=14y=24         //析构临时对象，由于这里没有被赋值给另一个对象
x = 14
y = 24
  
+++++++++++++++++++++
construct: x = 0 y = 0 //temp构造
where
copy construcor of this from p:(m_x=15,m_y=25) //生成临时对象
~Point():x=15y=25 //析构temp
~Point():x=15y=25 //析构临时对象，由于这里没有被赋值给另一个对象

~Point():x=13y=23        //析构ptt
~Point():x=15y=25        //析构最初的pt

*/