Inheritance in C++ Explained with Types, Syntax, and Examples | HackMNC Blog | HackMNC

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Inheritance in C++ is one of the four fundamental principles of Object-Oriented Programming (OOP). It allows a class (derived class) to acquire the properties and behaviors of another class (base class).

Using inheritance, developers can reuse existing code, build hierarchical relationships between classes, and make programs more modular and maintainable.

In this guide, you will learn:

What inheritance in C++ is
Syntax of inheritance
Different types of inheritance
Modes of inheritance
Practical C++ examples

What Is Inheritance in C++

Inheritance in C++ is one of the four pillars of Object-Oriented Programming (OOP). In inheritance, the properties and member functions of a base class (parent class) are inherited by the derived class (child class).

Why Use Inheritance in C++

Inheritance in C++ offers several advantages when designing object-oriented programs.

Code Reusability

Common functionality can be written once in the base class and reused in multiple derived classes.
Improved Code Organization

Classes can be structured in a logical hierarchy.
Easy Maintenance

Changes made in the base class automatically reflect in derived classes.
Extensibility

New features can be added by creating new derived classes without modifying existing code.

Syntax Of Inheritance In c++

cpp

#include<iostream>
#include<string>
using namespace std;
 
//base class
class Student{
    public:
    string name;
    int roll_number;
};
 
// derived class
class Club_Member: public Student{ 
    public:
    string domain;
    string role;
};
 
int main(){  
    Club_Member cm;
 
    cm.name  = "Gyan";        // inherited from Student class
    cm.roll_number = 2302080019; 
    cm.domain = "WebD";
    cm.role = "Backend Lead";
 
    return 0;

Mode Of Inheritance in C++

Base Class Member	Private Inheritance	Protected Inheritance	Public Inheritance
Private	Not Accessible	Not Accessible	Not Accessible
Protected	Private	Protected	Protected
Public	Private	Protected	Public

The mode of inheritance determines how the members of the base class are accessible in the derived class.

Types Of Inheritance in C++

C++ supports several types of inheritance in Object-Oriented Programming.

1. Single Inheritance

In single inheritance, one derived class inherits from a single base class.

cpp

//base class
class Student{
    public:
    string name;
    int roll_number;
};
 
// derived class
class Club_Member: public Student{ 
    public:
    string domain;
    string role;
};

2. Multi Level Inheritance

In multilevel inheritance, a class is derived from another derived class, forming a chain of inheritance.

cpp

// base class
class Person{
    public:
    string name;
    string gender;
 
};
 
// derived class 1
class Student: public Person{
    public:
    string department;
    int roll_number;
};
 
// derived class 2
class Club_Member: public Student{ 
    public:
    string domain;
    string role;
};

3. Multiple Inheritance

In multiple inheritance , one child class inherit properties and member functions from more than one parent class

cpp

// base class 1
class Person{
    public:
    string name;
    string gender;
 
};
// base class 2
class Student{
    public:
    string department;
    int roll_number;
};
// derived class 
class Club_Member: public Student , public Person{ 
    public:
    string domain;
    string role;
};

4. Hierarchical Inheritance

In hierarchical inheritance multiple child class inherit from a single parent class

cpp

// Parent class
class Person{
    public:
    string name;
    string gender;
 
};
// child class 1 / derived  class 1
class Student: public Person{
    public:
    string department;
    int roll_number;
};
// child class 2 / derived class 2 
class Club_Member: public Person{ 
    public:
    string domain;
    string role;
};

5. Hybrid Inheritance

In hybrid inheritance is a mixture of inheritance , there can be more than one inheritance

cpp

class Person{
public:
    string name;
};
 
class Student : public Person{
public:
    int roll;
};
 
class Sports{
public:
    string sport;
};
 
class Player : public Student, public Sports{
public:
    int ranking;
};

Real World Example Of Inheritance

cpp

class Vehicle{
public:
    int speed;
 
    void move(){
        cout << "Vehicle is moving" << endl;
    }
};
 
class Car : public Vehicle{
public:
    int gears;
};

Here, Car inherits properties of Vehicle. This allows the car object to use the move() function and speed variable.

Advantages of Inheritance in C++

Reduces code duplication
Improves maintainability
Supports polymorphism
Helps build hierarchical class relationships

Disadvantages of Inheritance in C++

Tight coupling between classes
Changes in base class affect derived classes
Can increase complexity in large systems

Difference Between Inheritance and Polymorphism in C++

Feature	Inheritance	Polymorphism
Purpose	Code reuse	Method behavior change
Relationship	IS-A	Same interface different behavior
Example	Car inherits Vehicle	Function overloading

How Inheritance Works in C++

In C++, inheritance allows a derived class to access the public and protected members of the base class. The derived class can also add new properties and methods or override existing ones.

Inheritance creates an "is-a" relationship between classes. For example, a Car is a type of Vehicle.

Key Takeaways

Inheritance allows a class to reuse properties and methods from another class.
The parent class is called the base class, and the child class is called the derived class.
C++ supports five types of inheritance: Single, Multilevel, Multiple, Hierarchical, and Hybrid.
Inheritance improves code reusability, maintainability, and modularity.
The mode of inheritance (public, private, protected) determines how base class members are accessed in the derived class.

FAQs on Inheritance in C++

What is inheritance in C++?

Inheritance in C++ is an OOP feature that allows a class to inherit properties and methods from another class.

What are the types of inheritance in C++?

C++ supports five types of inheritance: Single, Multilevel, Multiple, Hierarchical, and Hybrid.

What is the difference between inheritance and composition?

Inheritance represents an "is-a" relationship, while composition represents a "has-a" relationship.

What is the base class in C++?

A base class is the class whose properties and functions are inherited by another class.

Can private members be inherited in C++?

Private members are inherited but cannot be directly accessed in derived classes.

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