Why private method overwrites base class public virtual method(with public inheritance)?

Asked Apr 02 '19 at 13:20

Active Apr 02 '19 at 13:20

Viewed 55 times

Example code

#include <iostream>

class A 
{
    public :
     A() {}
     virtual void F() { std::cout << "A::f";}
};

class B: public A
{
    public:
     B() {}


    private:
      void F()  { std::cout << "B::f"; }
};

int main()
{
    B b;
    A * ptr = &b;
    ptr->F();
    return 0;
}

Method F() from class B overrides A::F() despite fact it's in private section not public. Why I cannot have private method B::F() which doesn't overrides A::F() ?

If virtuals works without checking private/public sections, maybe there should be any warning or error thrown?

asked Apr 02 '19 at 13:20

s.paszko

Why would you want such a thing? What problem are you trying to solve? – john Apr 02 '19 at 13:22
1

Not quite a dup like the one I closed with, but highly related and provides excellent rationale https://stackoverflow.com/questions/50722824/c-override-private-pure-virtual-method-as-public – StoryTeller - Unslander Monica Apr 02 '19 at 13:23
How would you then distinguish between these functions? `void B::G() { F(); }` - which `F`? – Daniel Langr Apr 02 '19 at 13:23
With namespace always `void B::G() { B::F(); }`. – s.paszko Apr 02 '19 at 13:27
1

@s.paszko Then, I don't understand your point. Why don't you simple name your private function a different way than `F`? – Daniel Langr Apr 02 '19 at 13:34
private/public are access specifiers -- they only control who outside your class is allowed to access the function. It has no bearing on the overRIDE (not overWRITE) mechanism in any way. – Chris Uzdavinis Apr 02 '19 at 13:45

Why private method overwrites base class public virtual method(with public inheritance)?

0 Answers0

Linked