Inheritance in oops

Sharda University
Department Of Computer Science And Engineering
School Of Engineering And Technology
Greater Noida, U. P.

Presented By
Hirra Sultan
CSE-B 2nd year
Roll No. 120101091
Enrollment No. 2012017740
Supervisor: Mr. A. K. Sahoo
prlhirr@gmail.com

Introduction
Background
 The first OOP language designed for the
first personal computer was smalltalk.
 When OOP was integrated into C
language, the resulting language was
called C++ and it became the first object-
oriented language to be widely used
commercially.
 Later java and other OOP languages were
developed.

Concept of Inheritance
 Inheritance is that feature of an OOP language
which allows reusability of code of a class and
is considered corner stone of OOP languages.
 Using inheritance, we can create a general
class that defines traits common to a set of
related items.
 This class may then be inherited by other,
more specific classes, each adding only those
things that are unique to the inheriting class.

 Base class: The class which gets inherited is
called a base class. The code of this class is
passed on to subclasses where it is reused.
 Derived class: A subclass is a derived class
which inherits the base class and uses its
member functions.
 Un-inheritable class: A class may be
declared as un-inheritable by adding certain class
modifiers to the class declaration before the
"class" keyword and the class identifier
declaration. Such sealed classes
restrict reusability.
Definitions

Types of Inheritance
 Single Inheritance: In single
inheritance there is only one super class
and only one sub class.
 Multi-level inheritance: In multi-level
inheritance a derived class is inherited by
another class thus making multiple levels.

 Multiple Inheritance: A class can inherit
the attributes of two or more classes. This
is known as multiple inheritance.
 Hierarchical inheritance: When a base
class is inherited by multiple derived
classes it is called hierarchical inheritance.
 Hybrid inheritance: This is a mixture of
two or more inheritances in a single code.

Inheritance may be derived in three forms
which decides the way inherited data
members can be used.
 Public Inheritance: Public members of
the base class become public members of
the derived class and protected members
of the base class
become protected members of the derived
class.

 Protected Inheritance: When
deriving from a protected base class, public
and protected members of the base class
become protected members of the derived
class.
 Private Inheritance: When deriving
from a private base class, public and
protected members of the base class
become private members of the derived
class.

Inheritance in C++
 In C++ all the five types of inheritances are
applicable.
 Friend functions and constructors can’t be
inherited.
 The general syntax of inheritance is:
class derived-class-name : visibility-mode base-
class-name
{
…// members of derived class
};

Inheritance in Java
 The general syntax of inheritance is:
Class Subclass-name extends superclass-
name
{
//methods and fields
}

 The keyword extends indicates that we are
making a new class that derives from an
existing class.
 Multiple and hybrid inheritance is not
supported. This reduces the program
complexity.
 Constructors are not inherited by a subclass.

Inheritance in Python
 Instances inherit from classes, and classes
inherit from super classes.
 Python supports a limited form of multiple
inheritance.
 The syntax for inheritance in python is:
class DerivedClassname
(BaseClassName):
<statement-1>
.
<statement-N>

Inheritance in ADA
 In Ada 95 terminology, types that can have
parents or children are termed “tagged
types”, and have the keyword “tagged” as
part of their definition.
 If we don't redefine a subprogram for a
given type, the closest ancestor's defined
subprogram will be used.

Advantages
 We save time because much of the code
needed for our class is already written.
 We can extend and revise a parent class
without corrupting the existing parent class
features.

Disadvantages
 Removing or swapping out a superclass
will usually break subclasses.
 It's inflexible.
 Inheritance relationships generally can't
be altered at runtime.

Inheritance in oops

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