Introduction To Inheritance | Inheritance

What is Inheritance?

Inheritance is one of the four fundamental principles of Object-Oriented Programming (OOP). It allows one class (the derived or child class) to inherit attributes and methods from another class (the base or parent class). This promotes code reusability and establishes a natural hierarchy between classes. Inheritance allows the derived class to inherit and override methods of the base class, which can be useful for extending functionality.

Why Use Inheritance?

Inheritance provides several benefits:

Code Reusability: You can use existing code without rewriting it.
Establishing a Natural Hierarchy: It creates a relationship between base and derived classes.
Extending Functionality: Derived classes can add new features or override existing ones.
Maintenance: Easier to manage and maintain code.

Basic Syntax of Inheritance

In C++, the syntax for inheritance involves the use of a colon (:) followed by the access specifier and the base class name.

class BaseClass {
    // Base class code
};

class DerivedClass : public BaseClass {
    // Derived class code
};

Types of Inheritance

There are different types of inheritance in C++:

Single Inheritance
Multiple Inheritance
Multilevel Inheritance
Hierarchical Inheritance
Hybrid Inheritance

Example of Single Inheritance

In single inheritance, a class inherits from one base class. Here's an example:

#include <iostream>
using namespace std;

class Base {
public:
    void show() {
        cout << "Base class method" << endl;
    }
};

class Derived : public Base {
public:
    void display() {
        cout << "Derived class method" << endl;
    }
};

int main() {
    Derived obj;
    obj.show();
    obj.display();
    return 0;
}

Base class method
Derived class method

Example of Multilevel Inheritance

In multilevel inheritance, a class is derived from another derived class. Here's an example:

#include <iostream>
using namespace std;

class Base {
public:
    void show() {
        cout << "Base class method" << endl;
    }
};

class Intermediate : public Base {
public:
    void display() {
        cout << "Intermediate class method" << endl;
    }
};

class Derived : public Intermediate {
public:
    void print() {
        cout << "Derived class method" << endl;
    }
};

int main() {
    Derived obj;
    obj.show();
    obj.display();
    obj.print();
    return 0;
}

Base class method
Intermediate class method
Derived class method

Access Specifiers in Inheritance

Access specifiers play an important role in inheritance. They define the accessibility of the base class members in the derived class:

public: Public members of the base class become public members of the derived class.
protected: Public and protected members of the base class become protected members of the derived class.
private: Public and protected members of the base class become private members of the derived class.

Conclusion

Inheritance is a powerful feature of C++ that allows for the creation of a new class by reusing the properties and behaviors of an existing class. It not only promotes code reusability but also helps in creating a natural hierarchical relationship between classes. With different types of inheritance, C++ provides a flexible way to extend and enhance the functionality of programs.

Introduction to Inheritance in C++