C++ Programming - OOPS Concepts - Discussion

Given answer is correct.

#include <iostream>
using namespace std;
class A
{
public:
void f() { cout << "A plain" << endl; }
};
class B : public A
{ public:
void f() { cout << "B plain" << endl; }
};
int main(){
A a;
B b;
a.f();
b.f();
}
o/p : A plain
B plain

Reason : It does so because methods of both classes are unknown to each other. They do need 'virtual' keyword if u intend to use method overriding i.e. Polymorphism which implemented using references and pointers.

This is wrong only base class is executed bcoj both have same prototype if we call them reverse ie base class as derived or vice versa then what is the difference between them.

Yes, if you don't give a virtual key word in base class, the function in the base-class gets executed even if you call derived class object. If you use the virtual key word before function in the base class you can call any of the function.

Please, anybody give me the right answer.

If virtual not used so only baser class function is called. If virtual keyword used so both can be called.

D option is correct without doubt. I agree with the given answer.

Yes, only base class function will be invoked irrespective of an object.

So, the answer is B.

Yes, it's B. Agree with the above explanation.

I think B is the right answer if you want to call a derive class same prototype function you have to use virtual concept.

Option B is correct. When we use virtual function for declaring base class then only it will calls to derived version of function as late binding takes place.

If we don't use virtual function for declaring base class then it will calls base class function. Because early binding takes place.