Write a program to implement multilevel inheritance in C++

🔷 Implementing Multilevel Inheritance in C++

Inheritance is a powerful concept in object-oriented programming that allows us to create a hierarchy of classes. One of the common and useful forms of inheritance in C++ is Multilevel Inheritance.

✅ What is Multilevel Inheritance?

Multilevel inheritance refers to a scenario where a class is derived from another derived class. This creates a chain of inheritance where:

• Class B inherits from Class A
• Class C inherits from Class B

This structure helps in extending the functionality and reusability of code over multiple levels of class hierarchy.

> 📌 Example: `Person → Employee → Manager`

🧠 Why Use Multilevel Inheritance?

• To model real-world hierarchical relationships.
• To reuse code across multiple levels of classes.
• To extend the functionalities of base classes in a structured manner.

🧑‍💻 C++ Program to Demonstrate Multilevel Inheritance

Let’s implement a simple program using three classes:

• `Person` – Base class (Level 1)
• `Employee` – Derived from `Person` (Level 2)
• `Manager` – Derived from `Employee` (Level 3)

#include <iostream>

using namespace std;

// Base Class - Level 1

class Person {

protected:

    string name;

    int age;

public:

    void setPerson(string n, int a) {

        name = n;

        age = a;

    }

    void showPerson() {

        cout << "Name: " << name << endl;

        cout << "Age: " << age << endl;

    }

};

// Derived Class - Level 2

class Employee : public Person {

protected:

    int empID;

    string department;

public:

    void setEmployee(int id, string dept) {

        empID = id;

        department = dept;

    }

    void showEmployee() {

        cout << "Employee ID: " << empID << endl;

        cout << "Department: " << department << endl;

    }

};

// Derived Class - Level 3

class Manager : public Employee {

private:

    int teamSize;

    string level;

public:

    void setManager(int tSize, string lvl) {

        teamSize = tSize;

        level = lvl;

    }

    void showManager() {

        showPerson();    // From Person

        showEmployee();  // From Employee

        cout << "Team Size: " << teamSize << endl;

        cout << "Manager Level: " << level << endl;

    }

};

int main() {

    Manager m1;

    m1.setPerson("Vivek Bhardwaj", 30);

    m1.setEmployee(101, "IT");

    m1.setManager(5, "Senior Manager");

    cout << "Manager Profile:\n";

    m1.showManager();

    return 0;

}

🖨️ Output

Manager Profile:

Name: Vivek Bhardwaj

Age: 30

Employee ID: 101

Department: IT

Team Size: 5

Manager Level: Senior Manager

📘 Explanation

• `Manager` inherits from `Employee`, which inherits from `Person`.
• All member functions and variables from `Person` and `Employee` are available to `Manager`.
• This multilevel structure models a real-world scenario where a manager is an employee, and an employee is a person.

📝 Conclusion

Multilevel inheritance in C++ provides a structured approach to model hierarchical relationships among classes. It promotes better code reuse, cleaner designs, and is essential in large-scale applications that involve real-world entities with tiered roles.

By understanding and applying multilevel inheritance, programmers can build flexible and extendable systems with minimal code redundancy.