C++ philosophy: Changing the accessibility of a class member should never change the meaning of a program.

 

代码

   
     

    
      
    
      #include 
    
      <
    
      iostream
    
      >
    
      

    
      using
    
       std::cout;

    
      using
    
       std::endl;

    
      class
    
       Base1{

    
      public
    
      :
 
    
      void
    
       foo(){cout
    
      <<
    
       
    
      "
    
      Base1::foo
    
      "
    
      <<
    
      endl;};
};


    
      class
    
       Base2{

    
      private
    
      :
 
    
      void
    
       foo(){cout
    
      <<
    
       
    
      "
    
      Base1::foo
    
      "
    
      <<
    
      endl;};
};


    
      class
    
       Dirived : 
    
      public
    
       Base1,
    
      public
    
       Base2{};


    
      int
    
       main(){
 Dirived d;
 d.foo();
 
    
      return
    
       
    
      0
    
      ;
}

   
     

 

d.foo();这一行编译器会报错 error: "Dirived::foo" is ambiguous

那么既然，Bas2的foo是一个私有函数，在Dirived类中并不可见，为什么编译器还傻傻的说ambiguous呢?