slicing problem

 

 

代码

   
     

    
      
    
      class
    
       Base{

    
      public
    
      :
 Base():m(
    
      0
    
      ){};
 
    
      //
    
      Base(const Base& rhs):m(rhs.m){cout<<"Copy constructor, rhs is "<<&rhs<<" this pointer is "<<this<<endl;}
    
      

    
       
    
      void
    
       add(){m
    
      ++
    
      ;};
 
    
      int
    
       m;
};

    
      class
    
       Derived : 
    
      public
    
       Base{};

    
      int
    
       main(){
 Derived d;
 cout
    
      <<
    
      d.m
    
      <<
    
      endl;
 static_cast
    
      <
    
      Base
    
      &>
    
      (d).add();
 cout
    
      <<
    
      d.m
    
      <<
    
      endl;
 
    
      //
    
      so called "slicing problem"
    
      

    
       static_cast
    
      <
    
      Base
    
      >
    
      (d).add();
 　 
    
      //
    
      Base(static_cast<Base&>(d)).add();
    
      

    
       cout
    
      <<
    
      d.m
    
      <<
    
      endl;
 
    
      return
    
       
    
      0
    
      ;
}
   
     

 

嘿嘿，猜猜看static_cast<Base>(d).add(); 这一行，编译器到底干了些什么.