C++虚函数的陷阱

首先看一段代码： 1 class B 2 { 3 public: 4     virtual void fun(int i = 1) 5     { 6         std::cout << "base fun called， " << i; 7     }; 8 }; 9 10 class D : public B 11 { 12 private: 13     virtual void fun(int i = 2) 14     { 15         std::cout << "driver fun called， " << i; 16     };