The document explains inheritance in object-oriented programming, which allows a derived class to inherit methods and attributes from a base class, promoting code reusability. It covers various types of inheritance such as single, multiple, multilevel, hierarchical, and hybrid inheritance, as well as concepts like method overriding and polymorphism. Additionally, it mentions practical resources for further learning about these concepts in Python.

1. Copyright © 2015 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
MIS 4395.A
Structured Programming
Language
Ahmed Imran Kabir
Week 11, Inheritance

2. Inheritance defined
Inheritance is a powerful feature in object oriented
programming.
It refers to defining a new class with little or no
modification to an existing class. The new class is
called derived (or child) class and the one from
which it inherits is called the base (or parent) class.
Python Inheritance Syntax
class BaseClass:
Body of base class
class DerivedClass(BaseClass):
Body of derived class
Derived class inherits features from the base class, adding new features to it. This results
into re-usability of code.

3. Characteristics of Inheritance
Inheritance makes objects (classes) special
Derive new classes from existing ones
Extend the definition of existing classes
Override method definitions of existing classes
Create objects of different classes in the same
program
Allow objects to communicate with each other
Create more complex objects by combining simpler
ones
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4. Inheritance Models “is a” Relationship
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Car
Van Sports car Convertible
Animals
Reptile Mammals Fish
Dog Cat Human

5. Using Inheritance to Create New
Classes
 Inheritance: An element of OOP that allows a new
class to be based on an existing one where the
new automatically gets (or inherits) all of the
methods and attributes of the existing class
 The children classes get all the capabilities
(methods) and properties (attributes) the parent
class has; the children classes are also called
derived classes
 Get the code for free! (code-reuse) – inheritance
allows a new class to re-use code which already
existed in another class (the parent class)
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6. Derived Classes are New Classes
 To create specializations of existing classes or
objects by adding new attributes and methods!
– often called subtyping when applied to classes. In
specialization, the new class or object has data or
behavior aspects that are not part of the inherited
class.
 Over-ridding (e.g., over-ridding of the + operator,
so + has different meaning, addition of two
numbers, concatenation of two strings, etc) – the
same method that does something different
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7. Altering the Behavior of Inherited
Methods: Overriding
 Override: To redefine how inherited method of
base class works in derived class
 Two choices when overriding
– Completely new functionality vs. overridden method
– Incorporate functionality of overridden method, add
more
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8. Understanding Polymorphism
 Polymorphism: Aspect of object-oriented
programming that allows you to send same
message to objects of different classes, related by
inheritance, and achieve different but appropriate
results for each object
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9. Working with Multiple Objects
 We can have multiple objects in a program
 Message: Communication between objects; one
object sends another a message when it invokes a
method of the other
(We already know that we can exchange
information among functions through parameters
and return values)
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10. Types of Inheritance
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11. Types of Inheritance
 Single Inheritance in Python
A single Python inheritance is when a single class
inherits from a class.
 Python Multiple Inheritance
Multiple Python inheritance are when multiple
python classes inherit from a class.
 Multilevel Inheritance in Python
When one class inherits from another, which in turn
inherits from another, it is multilevel python
inheritance.
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12. Types of Inheritance (Cont.)
 Hierarchical Inheritance in Python
When more than one class inherits from a class, it
is hierarchical Python inheritance.
 Hybrid Inheritance in Python
Hybrid Python inheritance is a combination of any
two kinds of inheritance.
 Examples to try at home:
https://data-flair.training/blogs/python-inheritance/
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13. Types of Inheritance
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14. Python Inheritance Super Function – Super()
 With inheritance, the super() function in
python actually comes in quite handy. It allows us
to call a method from the parent class. Let’s define
a new class for this.
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15. Python override method
 A subclass may change the functionality of
a Python method in the superclass. It does so by
redefining it. This is termed python method
overriding. Lets see this Python Method Overriding
Example.
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16. Conclusion
 For further practice on Object-oriented-
programming:
 https://en.wikipedia.org/wiki/Inheritance_(object-
oriented_programming)
 https://www.studytonight.com/python/types-of-
inheritance
 https://www.programiz.com/python-programming/
inheritance
 https://data-flair.training/blogs/python-inheritance/
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