c++中的继承关系

 #include <iostream>
  #include <string>
  #include <sstream>
  
  using namespace std;
  
 class Object
  {
  protected:
     string mName;
     string mInfo;
 public:
     Object()
     {
         mName = "Object";
         mInfo = "";
     }
     inline string getName()
     {
         return mName;
     }
     inline string getInfo()
     {
         return mInfo;
     }
 };
 
 class Point : public Object
 {
 private:
     int mX;
     int mY;
 public:
     Point(int x = 0, int y = 0)
     {
         ostringstream oss;
 
         mX = x;
         mY = y;
         mName = "Point";
         
         oss << "Point(" << mX << ", " << mY << ")";
         mInfo = oss.str();
     }
     inline int getX()
     {
         return mX;
     }
     inline int getY()
     {
         return mY;
     }
 };
 
 class Line : public Object
 {
 private:
     Point mP1;
     Point mP2;
 public:
     Line(Point p1, Point p2)
     {
         mP1 = p1;
         mP2 = p2;
         mName = "Line"; 
         mInfo = "Line from " + p1.getInfo() + " to " + p2.getInfo();
     }
     inline Point getStartPoint()
     {
         return mP1;
     }
     inline Point getEndPoint()
     {
         return mP2;
     }
 };
 
 int main(int argc, char const *argv[])
 {
     Object obj;
     cout << obj.getName() << endl;
     cout << obj.getInfo() << endl << endl;
 
     Point p1(1, 2);
     Point p2(3, 4);
     cout << p1.getName() << endl;
     cout << p1.getInfo() << endl;
     cout << p2.getName() << endl;
     cout << p2.getInfo() << endl << endl;
 
     Line line(p1, p2);
     cout << line.getName() << endl;
     cout << line.getInfo() << endl << endl;
 
     return 0;
 }