16.1.2: Inheritance - Types of Inheritance

Types of Inheritance in C++

1. Single Inheritance: In single inheritance, a class is allowed to inherit from only one class. i.e. one sub class is inherited by one base class only.
   Syntax:

   class subclass_name : access_mode base_class
   {
     //body of subclass
   };
   

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   // C++ program to explain 
   // Single inheritance 
   #include <iostream> 
   using namespace std; 
   
   // base class 
   class Vehicle { 
   public: 
       Vehicle() 
       { 
       cout << "This is a Vehicle" << endl; 
       } 
   }; 
   
   // sub class derived from two base classes 
   class Car: public Vehicle{ 
   
   }; 
   
   // main function 
   int main() 
   { 
       // creating object of sub class will 
       // invoke the constructor of base classes 
       Car obj; 
       return 0; 
   } 
   

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   // C++ program to explain  // Single inheritance #include <iostream> using namespace std;    // base class class Vehicle {   public:     Vehicle()     {       cout << "This is a Vehicle" << endl;     } };    // sub class derived from two base classes class Car: public Vehicle{    };    // main function int main() {        // creating object of sub class will     // invoke the constructor of base classes     Car obj;     return 0; }

   Output:

   This is a vehicle
   

2. Multiple Inheritance: Multiple Inheritance is a feature of C++ where a class can inherit from more than one classes. i.e one sub class is inherited from more than one base classes.
   Syntax:

   class subclass_name : access_mode base_class1, access_mode base_class2, ....
   {
     //body of subclass
   };
   

   Here, the number of base classes will be separated by a comma (‘, ‘) and access mode for every base class must be specified.

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   // C++ program to explain  // multiple inheritance #include <iostream> using namespace std;    // first base class class Vehicle {   public:     Vehicle()     {       cout << "This is a Vehicle" << endl;     } };    // second base class class FourWheeler {   public:     FourWheeler()     {       cout << "This is a 4 wheeler Vehicle" << endl;     } };    // sub class derived from two base classes class Car: public Vehicle, public FourWheeler {    };    // main function int main() {        // creating object of sub class will     // invoke the constructor of base classes     Car obj;     return 0; }

   Output:

   This is a Vehicle
   This is a 4 wheeler Vehicle
   

   Please visit this link to learn multiple inheritance in details.



3. Multilevel Inheritance: In this type of inheritance, a derived class is created from another derived class.filter_none

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   // C++ program to implement  // Multilevel Inheritance #include <iostream> using namespace std;    // base class class Vehicle  {   public:     Vehicle()     {       cout << "This is a Vehicle" << endl;     } }; class fourWheeler: public Vehicle {  public:     fourWheeler()     {       cout<<"Objects with 4 wheels are vehicles"<<endl;     } }; // sub class derived from two base classes class Car: public fourWheeler{    public:      car()      {        cout<<"Car has 4 Wheels"<<endl;      } };    // main function int main() {        //creating object of sub class will     //invoke the constructor of base classes     Car obj;     return 0; }

   output:

   This is a Vehicle
   Objects with 4 wheels are vehicles
   Car has 4 Wheels
   

4. Hierarchical Inheritance: In this type of inheritance, more than one sub class is inherited from a single base class. i.e. more than one derived class is created from a single base class.filter_none

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   // C++ program to implement  // Hierarchical Inheritance #include <iostream> using namespace std;    // base class class Vehicle  {   public:     Vehicle()     {       cout << "This is a Vehicle" << endl;     } };       // first sub class  class Car: public Vehicle {    };    // second sub class class Bus: public Vehicle {        };    // main function int main() {        // creating object of sub class will     // invoke the constructor of base class     Car obj1;     Bus obj2;     return 0; }

   Output:

   This is a Vehicle
   This is a Vehicle

Adapted from: "Inheritance in C++" by Harsh Agarwal, Geeks for Geeks is licensed under CC BY-SA 4.0