C++ 对象成员指针

Coordinate.h

class Coordinate{
public:
     Coordinate(int x, int y);
     ~Coordinate();
     int getX();
     int getY();
private:
     int m_iX;
     int m_iY;
};

Coordinate.cpp

#include<iostream>
#include "Coordinate.h"
using namespace std;

Coordinate::Coordinate(int x, int y)
{
      m_iX = x;
      m_iY = y;
      cout << "Coordinate(" << m_iX << "," << m_iY << ")" << endl;
}

Coordinate::~Coordinate()
{
     cout << "~Coordinate(" << m_iX << "," << m_iY << ")" << endl;
}

int Coordinate::getX()
{
      return m_iX;
}

int Coordinate::getY()
{
      return m_iY;
}

Line.h

#include "Coordinate.h"

class Line{
public:
      Line(int x1, int y1, int x2, int y2);
      ~Line();
      printInfo();
private:
      Coordinate *m_pCoorA;
      Coordinate *m_pCoorB;
};

Line.cpp

#include<iostream>
#include "Line.h"
using namespace std;

Line::Line(int x1, int y1, int x2, int y2)
{
      m_pCoorA = new Coordinate(x1, y1);
      m_pCoorB = new Coordinate(x2, y2);
      cout << "Line()" << endl;
}

Line::~Line()
{
      delete m_pCoorA;
      m_pCoorA = NULL;
      delete m_pCoorB;
      m_pCoorB = NULL;
      cout << "~Line()" << endl;
}

void Line::printInfo()
{
      cout << "(" << m_pCoorA->m_iX << "," << m_pCoorA->m_iY << ")" << endl;
       cout << "(" << m_pCoorB->m_iX << "," << m_pCoorB->m_iY << ")" << endl;
}

demo.cpp

#include<iostream>
#include "Line.h"
using namespace std;

int main()
{
     Line *p = new Line(1, 2, 3, 4);
     p->printInfo();
     delete p;
     p = NULL;
     cout << sizeof(p) << endl;
     cout << sizeof(Line) << endl;
     
     return 0;
}