What are virtual functions in C++? Explain how they enable polymorphism and dynamic method dispatching.

In C++, virtual functions play a crucial role in achieving polymorphism and dynamic method dispatching. They allow a program to determine the appropriate function to be executed based on the type of the object at runtime. Virtual functions enable code to be written in a more generic and flexible manner, facilitating the implementation of inheritance hierarchies and allowing objects of derived classes to be treated as objects of their base class. Let's explore the concept of virtual functions, their role in achieving polymorphism, and how they enable dynamic method dispatching.

1. Virtual Functions:
A virtual function is a member function declared in a base class that can be overridden by a derived class. By marking a member function as virtual in the base class, you indicate that it can have different implementations in the derived classes. The derived classes can override the virtual function to provide their own specific implementation while maintaining the same function signature.

To declare a virtual function, use the `virtual` keyword in the base class. The derived classes can override the virtual function using the `override` keyword to ensure that the function signature matches that of the base class.

Here's an example that demonstrates the usage of virtual functions:

```
cpp`class Shape {
public:
virtual void draw() {
cout << "Drawing a shape." << endl;
}
};

class Circle : public Shape {
public:
void draw() override {
cout << "Drawing a circle." << endl;
}
};

class Square : public Shape {
public:
void draw() override {
cout << "Drawing a square." << endl;
}
};

int main() {
Shape* shape1 = new Circle();
Shape* shape2 = new Square();

shape1->draw(); // Calls the overridden function in Circle
shape2->draw(); // Calls the overridden function in Square

delete shape1;
delete shape2;

return 0;
}`
```
In this example, the `Shape` class declares a virtual function `draw()`. The `Circle` and `Square` classes inherit from `Shape` and override the `draw()` function with their specific implementations. When calling the `draw()` function on objects of the base class type (`Shape*`), the appropriate overridden function is executed based on the actual type of the object.

2. Polymorphism and Dynamic Method Dispatching:
Virtual functions enable polymorphism, which means that objects of different derived classes can be treated as objects of their common base class. When a virtual function is called through a base class pointer or reference, the actual implementation of the function is determined at runtime based on the type of the object being referred to.

In the example above, both `shape1` and `shape2` are pointers of type `Shape*` pointing to objects of derived classes (`Circle` and `Square`). When the `draw()` function is called on these pointers, the appropriate overridden function in the derived class is executed.

This dynamic method dispatching is achieved through a mechanism called the vtable (virtual function table) or vptr (virtual pointer). Each object of a class with virtual functions contains a hidden vptr, which points to the vtable. The vtable is a table of function pointers that maps each virtual function to its appropriate implementation based on the class hierarchy.

During runtime, when a virtual function is called, the vptr is used to determine the correct function to be executed. This allows for the flexibility of calling the appropriate overridden function based on the actual type of the object being referred to, even though the reference or pointer is of the base class type.

Benefits of Virtual Functions:

* Polymorphism: Virtual functions enable polymorphism, allowing objects of derived classes to be treated as objects of their base class. This provides flexibility and ext