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OBJECT ORIENTED
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OOPs CONCEPT
INHERITANCE
Inheritance is the ability to define a new class or object that inherits the behaviour and its functionality of an existing class.
The new class or object is called a child or subclass or derived class while the original class is called parent or base class.
Definition(Inheritance) Inheritance is the mechanism which allows a class A to inherit properties of a class B. We say ``A inherits from B''.
Objects of class A thus have access to attributes and methods of class B without the need to redefine them.
Definition (Superclass/Subclass) If class A inherits from class B, then B is called superclass of A. A is called subclass of B.
Objects of a subclass can be used where objects of the corresponding superclass are expected. This is due to the fact that objects of the subclass
share the same behaviour as objects of the superclass.Superclasses are also called parent classes. Subclasses may also
called child classes or just derived classes.
figure:- Inheritance
A class can be derived from more than one classes, which means it can inherit data and functions from multiple base classes. To define a derived class,
we use a class derivation list to specify the base class(es). A class derivation list names one or more base classes and has the form:-
class derived-class: access-specifier base-class
Where access-specifier is one of public, protected, or private, and base-class is the name of a previously defined class. If the access-specifier is not used, then it is private by default.
Of course, you can again inherit from a subclass, making this class the superclass of the new subclass. This leads to a hierarchy of superclass/subclass
relationships. If you draw this hierarchy you get an inheritance graph.
Example :- In a software company Software Engineers, Sr. Software Engineers, Module Lead, Technical Lead, Project Lead, Project Manager,
Program Manager, Directors all are the employees of the company but their work, perks, roles, responsibilities differs. So in OOP, the Employee
base class would provide the common behaviours of all types/level of employee and also some behaviours properties that all employee must have for
that company. The particular sub class or child class of the employee would implement behaviours specific to that level of the employee.
So by above example you can notice that the main concept behind inheritance are extensibility and code reuse (in this case you are extending the
Employee class and using its code into sub class or derived class).
It is classifieds into different types, they are