C++ Abstract Class and Pure Virtual Function Example

✅ C++ Program: Abstract Class and Pure Virtual Functions

#include <iostream>
using namespace std;

// Abstract class
class Animal {
public:
    // Pure virtual function
    virtual void sound() = 0;
};

// Derived class Dog
class Dog : public Animal {
public:
    void sound() override {
        cout << "Dog barks 🐶\n";
    }
};

// Derived class Cat
class Cat : public Animal {
public:
    void sound() override {
        cout << "Cat meows 🐱\n";
    }
};

int main() {
    // Animal a;   ❌ ERROR: object of abstract class not allowed

    Animal *ptr;   // ✅ Abstract class pointer

    Dog d;
    Cat c;

    ptr = &d;
    ptr->sound();   // Calls Dog’s version

    ptr = &c;
    ptr->sound();   // Calls Cat’s version
}
  

📘 Explanation:

This program demonstrates the use of abstract classes and pure virtual functions in C++. Key points:

• Animal is an abstract class because it has a pure virtual function sound().
• You cannot create objects of abstract classes.
• You can create pointers of abstract class type and point them to derived objects.
• Runtime polymorphism ensures the correct function is called based on the object assigned.

🧾 Sample Output:

Dog barks 🐶
Cat meows 🐱
  

🔑 Keywords:

C++ abstract class, pure virtual function, runtime polymorphism, OOPs in C++, C++ class hierarchy

📌 Hashtags:

#CPlusPlus #AbstractClass #Polymorphism #OOP #CppInterview #VirtualFunctions

🔍 Search Description:

This C++ program demonstrates abstract classes and pure virtual functions using Animal, Dog, and Cat classes. Explains runtime polymorphism with sample output.