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Basics of Inheritance

NAMAN PANDEY 1424 19-Jun-2018
INHERITANCE:
Inheritance is a process in which properties of parent class are inherited by the child class.For example if there is a parent class and a child class and we declare a variable or method in the parent class we can use that in child class without declaring that variable or method again.
There following are the types of inheritance:
1) SINGLE INHERITANCE
Basics of Inheritance
Above diagram shows the concept of single inheritance.
In single inheritance base class derive the properties from only one parent class.
Syntax:
class subclass_name : access_mode base_class
{
  //body of subclass
};

EXAMPLE:

// 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:

Basics of Inheritance

In multiple inheritance properties of sub/chlid class are derived from from two super/parent classes.

EXAMPLE:

// 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

3) MULTILEVEL INHERITANCE:

Basics of Inheritance

In multilevel inheritance,a derived class is derived from another base class.

EXAMPLE:

// 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:

Basics of Inheritance

In hierarchical 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.

EXAMPLE:

// 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

5) HYBRID INHERITANCE:

Basics of Inheritance

Hybrid Inheritance is implemented by combining more than one type of inheritance. For example: Combining Hierarchical inheritance and Multiple Inheritance.

EXAMPLE:

// C++ program for Hybrid Inheritance 

#include <iostream>
using namespace std;
// base class
class Vehicle {
  public:     Vehicle()
    {
      cout << "This is a Vehicle" << endl;     } };
//base class
class Fare
{
    public:
    Fare()
    {
        cout<<"Fare of Vehicle\n";
    }
};
// first sub class
class Car: public Vehicle
{
};
// second sub class
class Bus: public Vehicle, public Fare
{
};
// main function
int main()
{
    // creating object of sub class will
    // invoke the constructor of base class
    Bus obj2;
    return 0;
}
Output:
This is a Vehicle
Fare of Vehicle

TYPES OF INHERITANCE SUPPORTED BY JAVA:

Three types of inheritance are supported by java which are:

1)Single Inheritance

2)Multilevel Inheritance

3)Hierarchical Inheritance

There are two more types of inheritance supported by java but through interface only:

1)Multiple Inheritance

2)Hybrid Inheritance

The reason that Java does not support multiple inheritances is that of the problem known as "diamond problem".


Updated 07-Sep-2019

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