c++ - 声明类和继承的冲突

Question

我有一个类 Point 和 Vector Vector 继承自 Point 并且 Point 使用 Vector 作为友元 我有一个 cpp 文件..我该如何解决这个冲突。 我不想使用头文件 我的代码是:

 class Vector:Point
 {
  //something
 };

 class Point
 {
 public:
     friend class Vector;

     double x;
     double y;
     Vector Point::operator-( Point Q)        // Vector diff of Points
     {
         Vector v;
         v.x = x - Q.x;
         v.y = y - Q.y;
         v.z = z - Q.z;
         v.dimn = max( dimn, Q.dim());
         return v;
     }

     Point Point::operator+( Vector v)        // +ve translation
     {
         Point P;
         P.x = x + v.x;
         P.y = y + v.y;
         P.z = z + v.z;
         P.dimn = max( dimn, v.dim());
         return P;
     }

     Point Point::operator-( Vector v)        // -ve translation
     {
         Point P;
         P.x = x - v.x;
         P.y = y - v.y;
         P.z = z - v.z;
         P.dimn = max( dimn, v.dim());
         return P;
     }

     Point& Point::operator+=( Vector v)        // +ve translation
     {
         x += v.x;
         y += v.y;
         z += v.z;
         dimn = max( dimn, v.dim());
         return *this;
     }

     Point& Point::operator-=( Vector v)        // -ve translation
     {
         x -= v.x;
         y -= v.y;
         z -= v.z;
         dimn = max( dimn, v.dim());
         return *this;
     }
};

Answer 1

尝试前向声明-

class Vector;
class Point { ... }