Source type not polymorphic

I want to be able to add the functionality (somehow) in red. Any ideas?

Code:

---

#include <iostream>
 
struct Foo{
 
  public:
    int getInt(){ return mInt; }
 
  protected:
    int mInt;
 
  friend class FooModifier;
};
 
class Bar : public Foo{
 
  public:
    char getChar(){ return mChar; }
 
  private:
    char mChar;
 
  friend class FooModifier;
};
 
class FooModifier{
 
  public:
    FooModifier( Foo* f )
    : mFoo( f ){}
 
    void setInt( int n ){ mFoo->mInt = n; }
    void setChar( char c ){ dynamic_cast<Bar*>(mFoo)->mChar = c; } // Source of problem
 
  private:
    Foo* mFoo;
};
 
 
int main(){
 
  Foo* f = new Foo();
  FooModifier fm(f);
  fm.setInt(5);
  std::cout << f->getInt() << "\n";
 
  Bar* b = new Bar();
  FooModifier fm2( dynamic_cast<Foo*>(b) );
  fm2.setInt(7);
  std::cout << b->getInt() << "\n";
 
  // Want to be able to modify both foo and bars
  fm2.setChar('k');
std::cout << b->getChar() << "\n";
 
  return 0;
}

---

You can add a virtual getter/setter.

assuming you haven't dumbed down the types you're using for the purposes of your example, you could use a polymorphic setter method. you can assign int to char just fine, it will just ignore the upper 3 bytes.

This design doesn't seem right to me. A Bar does not work like a Foo because a Bar has a char member that can be retrieved and set.

It would make more sense if Foo had virtual functions that could be called by FooModifier to handle all necessary tasks.
'
It seems as if Bar should really contain Foo, or they should be unrelated.

Nevermind, I don't need to be able to modify bar's extra stuff that foo doesn't havve. Sorry for the bother.