c++ - 递归友元类

Question

有没有办法解决这个问题:

class B;

class C { 
 public:
  C() { }
 private:
  int i;
  friend B::B();
};

class B { 
 public:
  B() { }
 private:
  int i;
  friend C::C();
};

给出错误:

prog.cpp:8: error: invalid use of incomplete type ‘struct B’
prog.cpp:1: error: forward declaration of ‘struct B’

Answer 1

你就是不能这样做。移除循环依赖。