11.0 - OOP Principles

*Inheritance

 the ability to create class/interface which inherits certain aspects from inherited parent

*Polymorphism

The word polymorphism means having many forms. In object-oriented programming paradigm, polymorphism is often expressed as 'one interface, multiple functions'.
Polymorphism can be static or dynamic. In static polymorphism, the response to a function is determined at the compile time. In dynamic polymorphism, it is decided at run-time.

Static Polymorphism

The mechanism of linking a function with an object during compile time is called early binding. It is also called static binding. C# provides two techniques to implement static polymorphism. They are:

• Function overloading
• Operator overloading

Dynamic Polymorphism

• C# allows you to create abstract classes that are used to provide partial class implementation of an interface. Implementation is completed when a derived class inherits from it. Abstract classes contain abstract methods, which are implemented by the derived class. The derived classes have more specialized functionality.
  Here are the rules about abstract classes:
  
• You cannot create an instance of an abstract class
• You cannot declare an abstract method outside an abstract class
• When a class is declared sealed, it cannot be inherited, 
• Abstract classes cannot be declared sealed.

* Encapsulation

Encapsulation, in the context of C#, refers to an object's ability to hide data and behavior that are not necessary to its user. Encapsulation enables a group of properties, methods and other members to be considered a single unit or object.

The following are the benefits of encapsulation:

• Protection of data from accidental corruption
• Specification of the accessibility of each of the members of a class to the code outside the class
• Flexibility and extensibility of the code and reduction in complexity
• Lower coupling between objects and hence improvement in code maintainability

Encapsulation is used to restrict access to the members of a class so as to prevent the user of a given class from manipulating objects in ways that are not intended by the designer. While encapsulation hides the internal implementation of the functionalities of class without affecting the overall functioning of the system, it allows the class to service a request for functionality and add or modify its internal structure (data or methods) to suit changing requirements.

Encapsulation is also known as information hiding.

Uses access modifiers

Encapsulation, in the context of C#, refers to an object's ability to hide data and behavior that are not necessary to its user. Encapsulation enables a group of properties, methods and other members to be considered a single unit or object.

* Abstraction

Abstraction from Object Oriented Programming perspective is extracting the core features of an object, without being specific about the implementation details.

helps reduce the complexity of the software