C# Fundamentals - Basics of OOPS

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iFour Consultancy
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Definition

• A markup language is a set of markup tags

• A markup language is a set of markup tags

• Programming language model organized around
  objects rather than "actions" and data rather
  than logic. Historically, a program has been
  viewed as a logical procedure that takes input
  data, processes it, and produces output data
• For a programming language to be a true OOP
  language, the language must meet the following
  criteria
• Abstraction
• Encapsulation
• Polymorphism
• Inheritance

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Fundamentals

• Classes and Objects
• The terms class and object are sometimes used
  interchangeably, but in fact, classes describe
  the type of objects, while objects are usable
  instances of classes. So, the act of creating an
  object is called instantiation. Using the
  blueprint analogy, a class is a blueprint, and an
  object is a building made from that blueprint
• Abstraction
• Abstraction manages the complexities of a
  business problem by allowing you to identify a
  set of objects involved with that business
  problem
• Encapsulation
• Encapsulation hides the internal implementation
  of an abstraction within the particular object
• Polymorphism
• It provides for multiple implementations of the
  same method. For example, different objects can
  have a Save method, each of which perform
  different processing
• Inheritance
• The excitement of Visual Basic .NET lies in
  inheritance. Visual Basic 5 introduced the
  concept of interface inheritance, which allows
  you to reuse the interface of a class, but not
  its implementation

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What is a class?

• It can be defined as a template/blueprint that
  describes the behaviors/states that object of its
  type support
• Example of simple class with member properties
  and member methods.
• public class Circle
• private decimal _radius
• public double radius getreturn _radius
  set_radius values
• public double Area()
• return 3.141592 _radius _radius

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What is Object?

• It represents a particular instance of a class.
  There can be more than one instance of an object.
  Each instance of an object can hold its own
  relevant data
• Example of Simple instantiate of an object of the
  class in the example of previous slides
• Circle objCircle new Circle() //here
  objCircle is an instance of a class
• Circle objCir new Circle() //here objCir is
  an instance of a class
• Both the instantiation(Objects) holds the related
  data and members of the class and can be used for
  different purposes

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Abstraction

• Example
• Real world example Laptop
• When derived class inherited with abstract class
  derived class must be override abstract class
  methods

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Encapsulation

• Hiding irrelevant data from the user
• A class may contain much information that is not
  useful for an outside class or interface
• So classes use encapsulation to hide its members
  that are not relevant for an outside class or
  interface
• It can be done using access specifiers
• In the same example of Circle class Private is
  a specifier used for Member variable. So It hides
  the data to be used outside the class
• private decimal _radius

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Inheritance

• Use in the small, when a derived class "is-a"
  base class
• enables code reuse
• enables design reuse polymorphic programming
• Example
• a Student is-a Person

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Inherited Methods
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Inherited Methods
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Polymorphism

• Static polymorphism
• Function overloading
• Operator overloading
• Dynamic Polymorphism
• abstract classes
• virtual functions

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Virtual and Overridden Methods
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Combining Method Overriding and Hiding
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Procedure v/s Object Oriented Programming

• It is a methodology to write the program where we
  specify the code in form of classes and objects
• Object-oriented programming is the successor of
  procedural (structural) programming
• Procedural programming describes programs as
  groups of reusable code units (procedures) which
  define input and output parameters. Procedural
  programs consist of procedures, which invoke each
  other
• The problem with procedural programming is that
  code reusability is hard and limited only
  procedures can be reused and it is hard to make
  them generic and flexible.
• There is no easy way to work with abstract data
  structures with different implementations
• This is how objects came to be. They describe
  characteristics (properties) and behaviour
  (methods) of such real life entities

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Interface

• Multiple Inheritance Support
• Example
• SmartPhone
• OS()
• AppStore()

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References

• https//www.tutorialspoint.com/csharp/
• http//www.c-sharpcorner.com/UploadFile/mkagrahar
  i/introduction-to-object-oriented-programming-conc
  epts-in-C-Sharp/

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• Thank You..

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