How do I use virtual functions in C++?

How do I use virtual functions in C++?

Virtual functions in C++ allow you to achieve polymorphism. You declare a function as virtual in a base class, and then you can override it in derived classes.

Can you give me an example of how to implement a virtual function?

Sure! Here's a simple example:

class Base {
public:
    virtual void show() {
        std::cout << "Base class show function called.";
    }
};

class Derived : public Base {
public:
    void show() override {
        std::cout << "Derived class show function called.";
    }
};

int main() {
    Base* b;
    Derived d;
    b = &d;
    b->show(); // Calls Derived's show()
}

What happens if I don't use the virtual keyword?

If you don't use the virtual keyword, the function call will be resolved at compile time, leading to static binding. This means the base class version will be called, even if you have a derived class object.

Are there any performance implications of using virtual functions?

Yes, there can be a slight performance overhead due to dynamic dispatch. However, the benefits of polymorphism often outweigh this cost.