Virtual Functions and V-Table Interview Questions Mock Test

Question 1: C++ OOPS Virtual Function Concept

What is a virtual function in C++?

Question 2: C++ OOPS Virtual Function Syntax

Which keyword is used to declare a virtual function in C++?

Question 3: C++ OOPS Virtual Function Example

What will be the output?

#include <iostream>
using namespace std;
class Base {
public:
    virtual void show() { cout << "Base"; }
};
class Derived : public Base {
public:
    void show() { cout << "Derived"; }
};
int main() {
    Base* b = new Derived();
    b->show();
}

Question 4: C++ OOPS Non-Virtual Function Call

What happens if virtual is removed in the above code?

Question 5: C++ OOPS Pure Virtual Function & V-Table

Which statement is true about pure virtual functions?

Question 6: C++ OOPS V-Table Concept

What is the V-Table in C++?

Question 7: C++ OOPS Multiple Inheritance & V-Table

How is V-Table affected in multiple inheritance?

Question 8: C++ OOPS Virtual Destructor Importance

Why should destructors be declared virtual in base classes?

Question 9: C++ OOPS V-Table and Object Size

How does adding virtual functions affect object size?

Question 10: C++ OOPS Virtual Function Override Example

What will be the output?

#include <iostream>
using namespace std;
class A { public: virtual void f() { cout << "A"; } };
class B : public A { public: void f() { cout << "B"; } };
class C : public B { public: void f() { cout << "C"; } };
int main() {
    A* p = new C();
    p->f();
}