Q.2 Solution......
Q.2 Explain Virtual and Pure Virtual function with example.
Solution :-
Virtual and Pure Virtual Functions in C++
In Object-Oriented Programming (OOP), the concept of polymorphism allows the same function name to behave differently depending on the type of object that calls it. In C++, this is mainly achieved through virtual functions and pure virtual functions.
1. Virtual Function
A virtual function is a member function in a base class that can be overridden in the derived class.
It is declared using the keyword
virtualinside the base class.When a base class pointer points to a derived class object, calling a virtual function ensures that the derived class version of the function is executed (this is called runtime polymorphism or dynamic binding).
Example: Virtual Function
#include <iostream>
using namespace std;
class Animal {
public:
virtual void sound() { // Virtual function
cout << "Animal makes a sound" << endl;
}
};
class Dog : public Animal {
public:
void sound() override {
cout << "Dog barks" << endl;
}
};
int main() {
Animal* a; // Base class pointer
Dog d;
a = &d; // Pointing to derived class object
a->sound(); // Calls Dog's version due to virtual function
return 0;
}
2. Pure Virtual Function
A pure virtual function is a virtual function that has no definition in the base class.
It is declared by assigning
= 0at the end of the function declaration.A class containing at least one pure virtual function is called an Abstract Class.
Objects cannot be created from abstract classes; they only serve as blueprints for derived classes.
Derived classes must override pure virtual functions; otherwise, they also become abstract.
Example: Pure Virtual Function
#include <iostream>
using namespace std;
class Shape {
public:
// Pure virtual function
virtual void draw() = 0;
};
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* s; // Base class pointer
Circle c;
Square sq;
s = &c;
s->draw(); // Calls Circle's draw()
s = &sq;
s->draw(); // Calls Square's draw()
return 0;
}