OOP in C# | PPL

Object Oriented programming in C#:

Object Oriented programming is a programming style which is associated with the concepts like class, object, Inheritance, Encapsulation, Abstraction, Polymorphism.
Class: A class is a collection of method and variables.

We can define a class using the class keyword and the class body enclosed by a pair of curly braces, as shown in the following example:

public class A
{

}

Inheritance: Inheritance feature allows code reusability when a class includes property of another class. In C# “:” is used to represent inheritance, as shown in the following example:

public class Papa {
 
}

class Child : Papa {

}

Objects: Object is a component of a program that knows how to perform certain actions and how to interact with other elements of the program, as shown in the following example:

Rectangle Rect = new Rectangle();

Here, Rectangle is a class, Rect is an object of class Rectangle, new is a keyword, Rectangle() is a constructor of class Rectangle.

Abstraction: Abstraction can be achieved using abstract classes in C#. Abstract classes contain abstract methods, which are implemented by the derived class.

Encapsulation: Encapsulation means bundling of data and methods within one unit, e.g., a class in C#. Encapsulation enables a programmer to implement the desired level of abstraction.

Polymorphism: Polymorphism means overloading and overriding, as shown in the following example:

Polymorphism overloading example:

using System;
namespace PolyOverloadingExample
{
 public class OverLoading
 {
   public void sum(int a, int b)
   {
     Console.WriteLine(a + b);
   }
   public void sum(int a, int b, int c)
   {
     Console.WriteLine(a + b + c );
   }
 }

}

Polymorphism overriding example:

using System;
namespace PolyOverridingExample
{
 public class Parent
 {
   public virtual void Show()
   {
     Console.WriteLine("Welcome");
   }
 }
 
 public class Child:Parent
 {
   public override void Show()
   {
     Console.WriteLine("Swagatam");
   }
 }

}

Viva Vice on OOP in C#

Q1. The capability of an object in Csharp to take number of different forms and hence display behaviour as according is known as:-

Ans. Polymorphism.

Q2. Which of the following keyword is used to change data and behavior of a base class by replacing a member of the base class with a new derived member?

Ans. New.

Q3. What is the correct way to overload +operator?

Ans. public sample operator + ( sample a, sample b), public abstract operator + (sample a,sample b). 

Q4. Selecting appropriate method out of number of overloaded methods by matching arguments in terms of number,type and order and binding that selected method to object at compile time is called?

Ans. Compile time polymorphism.

Q5. Correct syntax for while statement is:-

Ans. 

while(condition)

{

}


Principles of Programming Languages:

EasyExamNotes.com covered following topics in PPL.

• Language Evaluation Criteria
• Influences on Language Design 
• Language Categories
• Programming Paradigms
• Compilation
• Virtual Machines 
• Programming Environments
• Issues in Language Translation
• Parse Tree 
• Pointer and Reference type
• Concept of Binding
• Type Checking
• Strong typing 
• Sequence control with Expression
• Exception Handling 
• Subprograms
• Fundamentals of sub-programs
• Scope and lifetime of variable
• Static and dynamic scope
• Design issues of subprogram and operations
• Local referencing environments
• Parameter passing methods
• Overloaded sub-programs
• Generic sub-programs 
• Design issues for functions 
• Co routines 
• Abstract Data types
• Abstraction and encapsulation
• Static and Stack-Based Storage management
• Garbage Collection
• OOP in C++
• OOP in Java 
• OOP in C# 
• OOP in PHP
• Concurrency
• Semaphores 
• Monitors
• Message passing
• Java threads 
• C# threads 
• Exception handling 
• Exceptions
• Exception Propagation 
• Exception handler in C++ 
• Exception handler in Java
• Introduction and overview of Logic programming
• Basic elements of Prolog
• Application of Logic programming
• Functional programming languages
• Introduction to 4GL 

Practicals:

• Memory Implementation of 2D Array. 
• Memory Implementation of 3D Array. 
• Implementation of pointers in C++. 
• Write a program in Java to implement exception handling.
• Write a program in C++ to implement call by value parameter passing Method.
• Write a program in C++ to implement call by reference parameter passing Method. 
• Write a program in Java to implement concurrent execution of a job using threads.
• Implement Inheritance in C#.
• Implement Encapsulation in C#.
• Implement static/compiletime Polymorphism in C#.
• Implement dynamic/runtime Polymorphism in C#.

Previous years solved papers:

• PPL|RGPV|May 2018 
• PPL|RGPV|June 2017 

A list of Video lectures

• Click here

References:

1. Sebesta,”Concept of programming Language”, Pearson Edu 
2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley