How to hide a public function inherit from base class

Dracula Wang

I have 2 classes, B inherit from A, but actually A have a function: fun should not present in B, so I code as blow,

class A{
public:
virtual void fun(){cout << "a" << endl; };
};

class B : public A{
virtual void fun(){};
};

But this take no effect, I can call the fun in class b,

int main()
{
A a;
B b;
A *pa = new B;

a.fun();
b.A::fun();
pa->fun();

}

the output is

a
a

How to decline the function call? Thanks.

CPallini

What is your point? pa->fun() doesn't fit your needs?

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

Dracula Wang

yes, the A::fun() is bad for the B, will case error, so i want let A::fun to be public, but to B the fun must cannot be call

CPallini

What about (1) Writing A class without fun function. (2) Writing a (say) AA class that inherits from A and provides fun function. (3) Writing a B class that inherits from A class and therefore is not able to call fun function? Of course A class consumers should become AA class ones. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

Dracula Wang

yeah, that's the better way to do, but in this project others may dislike this implement, they didn't want their code update, @_@. Thanks for all your help.

BadKarma

Hi, I don't understand what you don't want to happen for the B class. do you want to hide the functionaly from a b object or the declaration; like this:

int main()
{
 A a;
 B b;

 a.fun();  //  outputs "a"
 b.fun();  //  compiles but doens't do something
 // or
 b.fun();  //  doens't compile

 A* p = &b;
 p->fun(); //  compiles but doens't do something

 b.A::fun();  // compiles but doens't do something
 
}

Maybe you could use the Facade pattern to hide the unwanted A functionaly.

Learn from the mistakes of others, you may not live long enough to make them all yourself.