Introduction

Question 1

What are the two main components of the .NET framework?

Answer 1

Class Library and
Common Language Runtime (CLR)

Question 2

What is the Common Language Runtime (CLR)?

Answer 2

The CLR is a virtual machine (software that manages the execution of programs and hides from them the underlying operating system and hardware).

It is responsible for managing the execution of .NET programs regardless of any .NET programming language.

Question 3

What is the Framework Class Library (FCL)?

Answer 3

It is the collection of reusable, object-oriented class libraries, also called the Assemblies.

It is just like the header files in C/C++ and packages in Java.

Question 4

What were the three types of applications?

Answer 4

WinForms: Windows Form-based applications.

ASP.NET: Web-based applications come under this category.

ADO.NET: It includes the application which are developed to communicate with the database like MS SQL Server, Oracle etc.

Question 5

What is WPF?

Answer 5

Windows Presentation Foundation (WPF) is a graphical subsystem given by Microsoft which uses DirectX and is used in Windows-based applications for rendering UI (User Interface).

Question 6

What is WCF?

Answer 6

Windows Communication Foundation (WCF) is used to communicate with cross-platform applications and to
develop network distributed applications.

Question 7

What is LINQ?

Answer 7

Language Integrated Query (LINQ) is a query language used to query the data sources with different .NET programming languages.

LINQ enables us to query any type of data source (databases, files, collections etc.).

Another benefit of using LINQ is that it provides IntelliSense and compile-time error checking.

Question 8

What is Common Type System (CTS)?

Answer 8

Common Type System (CTS) describes a set of types that can be used in different .NET languages in common.

Question 9

What is the garbage collection(GC)?

Answer 9

CLR also contains the Garbage Collector (GC), which runs in a low-priority thread and checks for un-referenced, dynamically allocated memory space.

If it finds some data that is no longer referenced by any
variable/reference, it re-claims it and returns it to the OS.

Question 10

Why is C# so popular and in demand?

Answer 10

1. Easy to Start
2. Widely used for developing Desktop and Web Application
3. Community
4. Game Development

Question 11

What are some characteristics of .NET Core?

Answer 11

• Cross platform: can run on different operating systems.
• Consistent Across Architectures: Runs your code with the same behavior on multiple architectures.
• Command-line Tools: Includes easy-to-use command-line tools that can be used for local development.
• Flexible Deployment: Can be included in your app or installed side-by-side user- or machine-wide
• Compatible: .NET Core is compatible with .NET Framework, Xamarin and Mono, via .NET Standard.
• Open-Source: The .NET Core platform is open source, using MIT and Apache licenses. .Net Core is .NET Foundation project.

Question 12

What is Visual Studio IDE?

Answer 12

Visual Studio IDE (Integrated Development Environment) is the
Development Environment for all .NET based applications.

Question 13

What is an Identifier?

Answer 13

An identifier is a name used to identify a class, variable, method, or any other user-defined item.

Question 14

What are keywords?

Answer 14

Keywords are reserved words predefined to the C# compiler.

get and set are contextual keywords.

Question 15

What is Type Inference?

Answer 15

Used through the var keyword, the compiler “infers” what the type of the variable is by what the variable is initialized to.

example.
var number = 10;

number is recognized as an int.

Question 16

What is a Verbatim String Literal?

Answer 16

Used through the @ symbol, the @ symbol tells the string constructor to ignore escape characters and line breaks.

Question 17

What is string interpolation

Answer 17

The insertion of values of variables into a string with simple syntax.

Question 18

What is a class?

Answer 18

A class is a construct that enables you to create your own custom types by grouping together variables of other types, methods and properties.

When you define a class, you define a blueprint for a data type.

Question 19

What is an instance?

Answer 19

A particular object of a class.

Question 20

How are classes and structs different?

Answer 20

Structs differ from classes because they do not need to be allocated on the heap.

Classes are reference types and are always allocated on the heap.

Structs are value types and are usually stored on the stack.

Question 21

What keyword do you use to declare an instance?

Answer 21

new

Question 22

What is the idea of a property?

Answer 22

The idea of a property is that it is a redesigned getter and setter function.

Question 23

What is the purpose of a property?

Answer 23

The purpose of a property is to get and/or set the field.

Question 24

Structs are what type?

Answer 24

Value.

This means they are stored in the stack and have the same lifetime restrictions as the simple data types.

Question 25

Do classes and structs support inheritance?

Answer 25

Classes support inheritance, structs do not.

Question 26

What is inheritance?

Answer 26

Inheritance is a form of software reuse in which a new class is created by absorbing an existing class’s members and enhancing them with new or modified capabilities.

Question 27

The existing class from which a new class inherits members is called

Answer 27

base class or parent class.

Question 28

What is single inheritance?

Answer 28

With single inheritance, one class can derive from one base class. This is a possible scenario with C#.

Question 29

What is multiple inheritance?

Answer 29

Multiple inheritance allows deriving from multiple base classes. C# does not support multiple inheritance with classes, but it allows multiple inheritance with interfaces.

Question 30

What is multilevel inheritance?

Answer 30

Multilevel inheritance allows inheritance across a bigger hierarchy. Class B derives from class A, and class C derives from class B. This is supported and often used with C#.

Question 31

What is interface inheritance?

Answer 31

Interface inheritance defines inheritance with interfaces. Here, multiple inheritance is possible.

Question 32

Describe a class’s public members

Answer 32

A class’s public members are accessible wherever the app has a reference to an object of that class.

Question 33

Describe a class’s private members

Answer 33

A class’s private members are accessible only within the class itself.

A base class’s private members are inherited by its derived classes but are not directly accessible by derived-class methods and properties.

Question 34

Using protected does what?

Answer 34

Using protected access offers an intermediate level of access
between public and private.

Question 35

What is polymorphism?

Answer 35

Polymorphism enables you to write apps that process objects that share the same base class in a class hierarchy as if they were all objects of the base class.

Question 36

What is static polymorphism?

Answer 36

In static polymorphism, the decision is made at compile-time.

Question 37

An example of static polymorphism is method overloading, what is it?

Answer 37

Method overloading is a concept where a class can have more than one method with the same name and different parameters.

Question 38

What is dynamic polymorphism?

Answer 38

In dynamic polymorphism, the decision is made at run-time.

Run-time polymorphism is achieved by method overriding.

Question 39

What are abstract classes?

Answer 39

These classes cannot be used to instantiate objects, because abstract classes are incomplete.

The purpose of an abstract class is primarily to provide an appropriate base class from which other classes can inherit, and thus share a common design.