Inheritance

Name: Vikas Choudhary.

 

Inheritance.

Introduction: It is a process in which one object acquires all the properties and behaviours of its parent object automatically. In such way, you can reuse, extend or modify the attributes and behaviours which are defined in other class.

·     Advantage of Inheritance: Advantage of inheritance is that you can reuse the members of your parent class. So, there is no need to define the member again. So less code is required in the class.

·     Types Of Inheritance:

C++ supports five types of inheritance:

 

fig.no.1 types of inheritance.

1. Single Inheritance: Single inheritance is defined as the inheritance in which a derived class is inherited from the only one base class.

fig.no.2 single inheritance.

Where 'A' is the base class, and 'B' is the derived class.

Example: 

When one class inherits another class, it is known as single level inheritance. Let's see the example of single level inheritance which inherits the fields only.

#include <iostream>  

using namespace std;  

 class Account {  

   public:  

   float salary = 60000;   

 };  

   class Programmer: public Account {  

   public:  

   float bonus = 5000;    

   };       

int main(void) {  

     Programmer p1;  

     cout<<"Salary: "<<p1.salary<<endl;    

     cout<<"Bonus: "<<p1.bonus<<endl;    

    return 0;  

}  

Output:

 

2.Multilevel Inheritance: Multilevel inheritance is a process of deriving a class from another derived class.

fig.no.3 multilevel inheritance.

When one class inherits another class which is further inherited by another class, it is known as multi level inheritance in C++. Inheritance is transitive so the last derived class acquires all the members of all its base classes.

Example:

#include <iostream>  

using namespace std;  

 class Animal {  

   public:  

 void eat() {   

    cout<<"Eating..."<<endl;   

 }    

   };  

   class Dog: public Animal   

   {    

       public:  

     void bark(){  

    cout<<"Barking..."<<endl;   

     }    

   };   

   class BabyDog: public Dog   

   {    

       public:  

     void weep() {  

    cout<<"Weeping...";   

     }    

   };   

int main(void) {  

    BabyDog d1;  

    d1.eat();  

    d1.bark();  

     d1.weep();  

     return 0;  

}  

Output:

 

 3.Multiple Inheritance: Multiple inheritance is the process of deriving a new class that inherits the attributes from two or more classes.

fig.no.4 multiple inheritance.

Example:

#include <iostream>  

using namespace std;  

class A  

{  

    protected:  

     int a;  

    public:  

    void get_a(int n)  

    {  

        a = n;  

    }  

};  

  

class B  

{  

    protected:  

    int b;  

    public:  

    void get_b(int n)  

    {  

        b = n;  

    }  

};  

class C : public A,public B  

{  

   public:  

    void display()  

    {  

        std::cout << "The value of a is : " <<a<< std::endl;  

        std::cout << "The value of b is : " <<b<< std::endl;  

        cout<<"Addition of a and b is : "<<a+b;  

    }  

};  

int main()  

{  

   C c;  

   c.get_a(10);  

   c.get_b(20);  

   c.display();  

  

    return 0;  

} 

Output:

 4.Hybrid Inheritance: Hybrid inheritance is a combination of more than one type of inheritance.

fig.no.5 hybrid inheritance.

Example:

#include <iostream>  

using namespace std;  

class A  

{  

    protected:  

    int a;  

    public:  

    void get_a()  

    {  

       std::cout << "Enter the value of 'a' : " << std::endl;  

       cin>>a;  

    }  

};  

  

class B : public A   

{  

    protected:  

    int b;  

    public:  

    void get_b()  

    {  

        std::cout << "Enter the value of 'b' : " << std::endl;  

       cin>>b;  

    }  

};  

class C   

{  

    protected:  

    int c;  

    public:  

    void get_c()  

    {  

        std::cout << "Enter the value of c is : " << std::endl;  

        cin>>c;  

    }  

};  

  

class D : public B, public C  

{  

    protected:  

    int d;  

    public:  

    void mul()  

    {  

         get_a();  

         get_b();  

         get_c();  

         std::cout << "Multiplication of a,b,c is : " <<a*b*c<< std::endl;  

    }  

};  

int main()  

{  

    D d;  

    d.mul();  

    return 0;  

}

Output:

 

5.Hierarchical Inheritance: Hierarchical inheritance is defined as the process of deriving more than one class from a base class.

fig.no.6 hierarchical inheritance.

Example:

#include <iostream>  

using namespace std;  

class Shape                 

{  

    public:  

    int a;  

    int b;  

    void get_data(int n,int m)  

    {  

        a= n;  

        b = m;  

    }  

};  

class Rectangle : public Shape  

{  

    public:  

    int rect_area()  

    {  

        int result = a*b;  

        return result;  

    }  

};  

class Triangle : public Shape    

{  

    public:  

    int triangle_area()  

    {  

        float result = 0.5*a*b;  

        return result;  

    }  

};  

int main()  

{  

    Rectangle r;  

    Triangle t;  

    int length,breadth,base,height;  

    std::cout << "Enter the length and breadth of a rectangle: " << std::endl;  

    cin>>length>>breadth;  

    r.get_data(length,breadth);  

    int m = r.rect_area();  

    std::cout << "Area of the rectangle is : " <<m<< std::endl;  

    std::cout << "Enter the base and height of the triangle: " << std::endl;  

    cin>>base>>height;  

    t.get_data(base,height);  

    float n = t.triangle_area();  

    std::cout <<"Area of the triangle is : "  << n<<std::endl;  

    return 0;  

}  

Output:

Conclusion: Inheritance is one of the most important components of the object oriented programming and in turns the hierarchies of inheritance classes. inheritance is used with the base or parent class via the derived class. the c++ supports both simple and multiple inheritance. the programmer is concerned with public inheritance. At the end of the inheritance conclusion, inheritance is just a convenience for the programmer.