Test and Theory Question for each levels

Level 0 Test

1. FizzBuzz: write a program that prints numbers from 1 to 100. However, for multiples of three, “Fizz” should be printed instead of the number, and for multiples of five, “Buzz” should be printed. For numbers that are multiples of both three and five, “FizzBuzz” should be printed.
2. Palindrome Checker: write a function that determines whether a given string is a palindrome or not. A palindrome is a word, phrase, or sequence of characters that reads the same backward as forward. For example, “radar” and “level” are palindromes. ( Others are Radar, Level, Madam, Civic, Deed, Kayak, Noon, Racecar, Redder, Rotator)
3. Prime Number Generator: Challenge the programmer to write a program that generates prime numbers up to a given limit. The program should output a list of all prime numbers within the specified range. (prime numbers 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 These numbers are prime because they are only divisible by 1 and themselves without any remainder)
4. Fibonacci Sequence: write a function that generates the Fibonacci sequence up to a specified number of terms. The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding ones. For example, the sequence starts as 0, 1, 1, 2, 3, 5, 8, 13, and so on.

Level 1 Test

1. Sorting Algorithms: implement sorting algorithms such as bubble sort, insertion sort, or quicksort. Provide a list of numbers and ask them to demonstrate their knowledge by implementing one or more sorting algorithms to sort the list.
2. String Manipulation: write a function that reverses a string without using any built-in reverse functions or libraries.
3. Object-Oriented Programming (OOP): design a simple banking system with classes like Account, Customer, and Transaction.
4. Exception Handling: write a program that includes exception handling or adding exception handling in sample code – we attempt to parse user input as an integer and then divide 10 by the provided number. If any exceptions occur during this process, they are caught and handled accordingly. Should Handle Invalid Number or Division by zero through exception handling and any other exceptions are caught by the generic Exception catch block and displays a user-friendly error message. After handling the exception, the program continues its execution.

using System;

class Program
{
    static void Main()
    {
            Console.WriteLine("Enter a number: ");
            string input = Console.ReadLine();
            int number = int.Parse(input);

            int result = 10 / number;

            Console.WriteLine("Result: " + result);

        Console.WriteLine("Program execution continues...");
        Console.ReadLine();
    }
}

1. File Handling: write a program that reads data from a text file, performs some operations or manipulations, and writes the results to another file.

Test Case: Check for prime numbers from text file
Test: Read, Write, Error Handling and Invalid Data Handling

Test Steps:

Create a test input file "input.txt" with 1-100 numbers on each line plus some alphabets A,B,C D etc.

Execute the program.
reads the data from "input.txt" 
check if it is a prime number
writes prime numbers to a new file "prime_numbers.txt"

Note:
program should detects the absence of the input file and handles the file not found exception appropriately and displays a user-friendly error message.

program should detects the invalid data, Not Number, and displays a user-friendly error message.

1. Database Interaction: write a program that connects to a database (such as SQL Server), performs basic CRUD (Create, Read, Update, Delete) operations on a table, and displays the results.

Level 3 Test – Incomplete

1. Data Structures: implement a specific data structure, such as a linked list, stack, queue, or binary tree.
2. Recursion: write a recursive function to solve a specific problem. For example, write a recursive function to calculate the factorial of a number or to find the nth term in the Fibonacci sequence using recursion.
3. Regular Expressions: with a text pattern and ask them to write a regular expression that matches strings following that pattern. This test evaluates their understanding of regular expressions and their ability to use them effectively in C#.
4. Design Patterns: identify and explain various design patterns used in object-oriented programming and provide examples of scenarios where these patterns can be applied. implement a specific design pattern in a given context.
5. API Integration: integrate with an external API using C#. write code to make requests, handle responses, and process data.
6. Unit Testing: write unit tests for a given piece of code or a specific function. write meaningful tests, cover different scenarios, and assert the expected outcomes.
7. Multithreading: write a program that demonstrates the use of multithreading in C#. create multiple threads to perform simultaneous tasks or implement thread synchronization mechanisms.

Level 4 Test – Incomplete

1. LINQ Queries: write LINQ queries to perform various operations on a given collection of objects. Test their understanding of LINQ operators such as Where, Select, OrderBy, GroupBy, etc., and their ability to write expressive and efficient queries.
2. Asynchronous Programming: write an asynchronous C# program that performs a time-consuming task, such as downloading multiple files concurrently or making API requests in parallel. Evaluate their knowledge of asynchronous programming concepts and their ability to use async/await and Task objects effectively.
3. Serialization and Deserialization: implement serialization and deserialization methods using XML or JSON formats. Assess their understanding of data serialization concepts and their ability to use serialization libraries or write custom serialization code.
4. Performance Optimization: Present a piece of code that performs a specific task and ask the programmer to optimize it for better performance. Evaluate their ability to analyze and identify performance bottlenecks, apply optimization techniques such as caching, lazy loading, or algorithmic improvements, and measure the impact of their optimizations.
5. Web Development: build a simple web application or API using ASP.NET Core. Provide them with requirements such as data retrieval, CRUD operations, authentication, or authorization, and assess their ability to build a functional and secure web application using C#.
6. Code Review: Instead of providing a specific programming task, you can ask the programmer to review and provide feedback on a given code snippet. This can help evaluate their ability to understand and assess code quality, identify potential bugs or issues, and suggest improvements or best practices.

Level 5 Test – Incomplete

1. Networking: write a C# program that implements a simple client-server communication using TCP or UDP sockets. Ask them to demonstrate their knowledge of socket programming, handling multiple connections, and exchanging data between the client and server.
2. Error Handling and Logging: Provide with a piece of code that contains potential errors or exceptions. Ask them to identify the issues, implement proper error handling techniques, and incorporate logging to track and record errors or application events.
3. Dependency Injection: Present a scenario where multiple classes need to be instantiated and interact with each other. Ask the programmer to refactor the code using a dependency injection framework such as Microsoft.Extensions.DependencyInjection to manage object creation, lifetime, and dependencies.
4. Web Scraping: write a C# program that scrapes data from a website using a web scraping library or framework like HtmlAgilityPack or Selenium. Ask them to extract specific information from the website and store it in a structured format.
5. Parallel Programming: Rwrite a program that performs a computationally intensive task in parallel using techniques like parallel loops, tasks, or Parallel LINQ (PLINQ). Evaluate their ability to leverage parallel processing to improve performance and handle synchronization or concurrency issues.
6. Encryption and Decryption: implement a program that encrypts or decrypts data using symmetric or asymmetric encryption algorithms such as AES or RSA. Evaluate their understanding of encryption concepts, key management, and security practices.

Level 6 Test – Incomplete

1. Design and Implement a RESTful API: design and implement a RESTful API using ASP.NET Web API or ASP.NET Core. Provide them with the requirements for endpoints, request/response formats, authentication, and any other necessary specifications. Evaluate their ability to create a well-structured and functional API.
2. Database Query Optimization: Provide a database schema and a sample query that retrieves data from multiple tables. optimize the query for performance, taking into account indexes, joins, and other database optimization techniques.
3. Design and Implement a Data Access Layer: design and implement a data access layer (DAL) using an Object-Relational Mapping (ORM) tool like Entity Framework or Dapper. Evaluate their ability to create efficient data access code, handle relationships between tables, and perform CRUD operations.
4. Implement a Caching Mechanism: implement a caching mechanism in a C# program. This could involve caching data retrieved from a database, caching the results of computationally expensive operations, or using a caching library like Redis or MemoryCache. Assess their understanding of caching principles, expiration policies, and cache invalidation strategies.
5. Implement a Multithreaded Application: develop a multithreaded application that leverages multiple threads to perform concurrent tasks efficiently. This could involve dividing a large workload into smaller tasks and processing them concurrently, while managing thread synchronization and coordination.
6. Code Refactoring: Provide with a piece of code that is poorly written, hard to maintain, or violates best practices. Ask them to refactor the code to improve readability, maintainability, and performance. Evaluate their ability to identify code smells, apply design patterns, and write clean, modular code.

Level 7 Test – Incomplete

1. Parallel Processing: write a program that performs a computationally intensive task in parallel using the Task Parallel Library (TPL) or Parallel LINQ (PLINQ). Evaluate their ability to leverage parallel processing to improve performance and handle synchronization or concurrency issues.
2. Reflection: use reflection to inspect and manipulate types, members, or attributes at runtime. Ask them to write code that dynamically loads assemblies, discovers classes, and invokes methods using reflection.
3. Code Optimization: Provide with a piece of code that can be optimized for better performance or memory usage. Ask them to identify areas for improvement and modify the code to make it more efficient or use fewer resources.
4. Unit Testing with Mocking: write unit tests for a class or method that has external dependencies. Evaluate their ability to use mocking frameworks like Moq or NSubstitute to isolate the unit under test and verify its behavior.
5. Asynchronous Streaming: implement an asynchronous streaming mechanism using C# 8.0’s IAsyncEnumerable and await foreach construct. Ask them to write code that asynchronously generates and consumes a sequence of data.
6. Secure Coding: Present a scenario that involves handling sensitive data, authentication, or input validation. write code that adheres to secure coding practices, such as using parameterized queries to prevent SQL injection or implementing proper authentication and authorization mechanisms.

THEORY

Level 1 Theory

1. What is C#? How does it differ from other programming languages?
2. Explain the difference between value types and reference types in C#.
3. What are the access modifiers available in C#? Explain each one.
4. Describe the concept of inheritance in C#. How does it promote code reusability?
5. What is the purpose of the “using” statement in C#? How does it help with resource management?
6. How do you handle exceptions in C#? Explain the try-catch-finally block.
7. What is the difference between an abstract class and an interface in C#? When would you use each one?
8. How do you implement multithreading in C#? Explain the Thread class and the Task class.
9. What is LINQ (Language Integrated Query)? How does it simplify data querying and manipulation in C#?
10. How do you work with databases in C#? Explain the ADO.NET framework and its key components.

Level 2

11. What are delegates in C#? How are they different from interfaces?
12. Explain the concept of generics in C#. How can they improve code reuse and type safety?
13. What is the purpose of the “var” keyword in C#? When would you use it?
14. How do you handle asynchronous programming in C#? Explain the “async” and “await” keywords.
15. Describe the concept of events and event handling in C#. How do you subscribe to and raise events?
16. What are the different types of collections available in C#? Explain when you would use each one.
17. How do you implement object serialization and deserialization in C#? Explain the Serializable attribute and the BinaryFormatter class.
18. What is the purpose of the “yield” keyword in C#? How does it relate to iterators?
19. Explain the concept of extension methods in C#. How do they enhance code readability and reusability?
20. How do you implement dependency injection in C#? Describe the benefits of using an IoC (Inversion of Control) container.

Level 3

21. What are the different types of exceptions in C#? How do you handle specific types of exceptions?
22. Explain the concept of delegates and events in C#. How do you use them to implement the observer pattern?
23. What is the purpose of the “readonly” keyword in C#? How does it differ from the “const” keyword?
24. How do you implement and consume a Web API in C#? Explain the key components involved.
25. What is the purpose of the “async” and “await” keywords in C#? How do they relate to asynchronous programming?
26. Describe the concept of garbage collection in C#. How does it help manage memory resources?
27. How do you work with files and directories in C#? Explain the key classes and methods available in the System.IO namespace.
28. What is the role of attributes in C#? Provide examples of built-in attributes and explain how to create custom attributes.
29. How do you implement logging in a C# application? Explain the importance of logging and discuss different logging frameworks available.
30. What are some best practices for writing clean and maintainable C# code? Discuss topics such as naming conventions, code organization, and error handling.

Level 4

31. What is the difference between a struct and a class in C#? When would you use each one?
32. Explain the concept of interfaces in C#. How do they support multiple inheritance?
33. How do you implement authentication and authorization in a C# web application? Explain the role of ASP.NET Identity.
34. What is the purpose of the “using” directive in C#? How does it help with namespace management?
35. Describe the concept of reflection in C#. How do you use reflection to inspect types and invoke methods dynamically?
36. How do you implement caching in a C# application? Discuss different caching techniques and frameworks available.
37. What are anonymous types in C#? How do you create and use them?
38. Explain the concept of extension methods in C#. How do you extend existing types with custom functionality?
39. How do you implement unit testing in a C# application? Discuss popular unit testing frameworks and their key features.
40. What are the new features introduced in the latest versions of C# (C# 7, C# 8, C# 9)? Discuss any that you are familiar with and how they improve the language.

Level 5

41. How do you implement asynchronous programming using the Task Parallel Library (TPL) in C#? Explain the benefits and considerations.
42. What are attributes in C#? How do you use them for metadata and customization?
43. Explain the concept of dependency injection (DI) and inversion of control (IoC) containers in C#. How do they improve code maintainability and testability?
44. Describe the concept of asynchronous streams in C#. How do you consume and produce data asynchronously using IAsyncEnumerable?
45. How do you handle concurrency and synchronization in C#? Discuss the various mechanisms available, such as locks, monitors, and concurrent collections.
46. What is the role of the Entity Framework in C#? How do you use it for object-relational mapping (ORM) and database access?
47. Explain the difference between value types and reference types in C#. When and why would you choose one over the other?
48. How do you implement logging and error handling in a C# application? Discuss different logging frameworks and strategies for capturing and handling exceptions.
49. Describe the concept of asynchronous messaging using the Message Queueing Telemetry Transport (MQTT) protocol in C#. How does it enable reliable and scalable communication?
50. How do you optimize the performance of a C# application? Discuss techniques such as caching, code profiling, and performance profiling tools.

Level 6

51. What is the purpose of the “using” statement in C#? How does it relate to IDisposable and resource management?
52. Explain the concept of polymorphism in C#. How does it enable code flexibility and extensibility?
53. How do you work with asynchronous programming patterns in C#? Discuss the differences between callbacks, events, and async-await.
54. What is the purpose of the “params” keyword in C#? How does it allow for variable-length parameter lists?
55. Describe the concept of serialization and deserialization in C#. How do you convert objects to/from a binary or XML format?
56. How do you work with JSON data in C#? Discuss popular JSON frameworks and their usage.
57. Explain the concept of iterators and the yield return statement in C#. How do they simplify the implementation of enumerable sequences?
58. How do you implement caching in a C# application? Discuss different caching techniques and caching frameworks.
59. Describe the concept of reflection in C#. How do you use reflection to inspect and manipulate objects at runtime?
60. What are the differences between the “const” and “readonly” keywords in C#? When would you use each one?

Level 7

61. How do you handle concurrency and thread synchronization in C#? Discuss different synchronization mechanisms like locks, mutexes, and semaphores.
62. What are anonymous methods and lambda expressions in C#? How do you use them to simplify code and improve readability?
63. Explain the concept of partial classes in C#. How do they enable code separation and collaboration?
64. How do you work with asynchronous streams in C# 8 and later? Discuss the benefits and usage of IAsyncEnumerable and await foreach.
65. What are indexers in C#? How do you implement and use them in a class?
66. Describe the concept of code contracts in C#. How do they help with design by contract and program correctness?
67. How do you implement parallel programming in C#? Discuss the Task Parallel Library (TPL) and the use of parallel loops and tasks.
68. Explain the concept of data binding in C#. How do you bind data to UI controls in frameworks like WPF or WinForms?
69. How do you handle file I/O operations in C#? Discuss different file access techniques and file handling classes.
70. Describe the concept of aspect-oriented programming (AOP) in C#. How do you use frameworks like PostSharp to implement cross-cutting concerns?

Level 8

71. What is the difference between shallow copy and deep copy in C#? How do you implement each type of copy?
72. How do you implement asynchronous communication using messaging frameworks like RabbitMQ or Azure Service Bus in C#?
73. Explain the concept of attributes in C#. How do you define and apply custom attributes to classes, methods, or properties?
74. How do you implement parallel processing in C# using the Parallel class? Discuss the benefits and considerations.
75. What is the purpose of the “volatile” keyword in C#? When and why would you use it?
76. How do you implement logging and error handling in a distributed C# application? Discuss approaches for centralized logging and error tracking.
77. Describe the concept of parallel LINQ (PLINQ) in C#. How does it enable efficient data processing on multi-core processors?
78. How do you work with databases using Entity Framework Core in C#? Discuss migrations, querying, and entity relationships.
79. Explain the concept of dependency injection (DI) containers in C#. How do you configure and use DI containers like Autofac or Unity?
80. What are the differences between the “is” and “as” operators in C#? How do you use them for type checking and casting?

Level 9

81. What is the difference between covariance and contravariance in C#? How do you use them in delegate types and generic interfaces?
82. Explain the concept of parallel programming using the Task Parallel Library (TPL) in C#. How do you handle exceptions in parallel code?
83. How do you implement caching strategies in a web application using C#? Discuss techniques like in-memory caching, distributed caching, and cache invalidation.
84. Describe the concept of localization and globalization in C#. How do you implement multi-language support in an application?
85. What is the purpose of the “async” modifier in C#? How does it affect the method behavior and return type?
86. Explain the concept of reflection.emit in C#. How do you dynamically generate and execute code at runtime?
87. How do you work with XML data in C#? Discuss different XML parsing and manipulation techniques, such as XmlDocument and LINQ to XML.
88. Describe the concept of design patterns in C#. Discuss some commonly used design patterns and their implementation.
89. How do you work with network communication in C#? Discuss socket programming, TCP/IP, and HTTP-based communication.
90. What are extension properties in C#? How do you define and use them to extend existing classes?

Level 10

91. Explain the concept of async streams in C# 8 and later. How do you use them to asynchronously produce and consume sequences of data?
92. How do you implement authentication and authorization in a C# web application? Discuss different authentication mechanisms and authorization techniques.
93. What are the different types of serialization available in C#? Explain the differences between binary serialization, XML serialization, and JSON serialization.
94. How do you work with asynchronous database operations in C#? Discuss techniques such as asynchronous database calls and async database providers.
95. Describe the concept of parallel query execution in C#. How does PLINQ enable parallel execution of queries on collections?
96. Explain the concept of memory management in C#. How does the garbage collector work, and what are some best practices for efficient memory usage?
97. How do you implement concurrent data structures in C#? Discuss the ConcurrentDictionary, ConcurrentQueue, and ConcurrentStack classes.
98. Describe the concept of functional programming in C#. How do you use features like lambda expressions and LINQ to write functional-style code?
99. How do you optimize performance in a C# application? Discuss techniques such as code profiling, caching, and algorithm optimization.
100. What are some best practices for writing secure code in C#? Discuss topics such as input validation, parameterized queries, and secure storage of sensitive information.

Level 11

101. Explain the concept of asynchronous socket programming in C#. How do you handle asynchronous communication using the Socket class?
102. Describe the SOLID principles in object-oriented programming. How do you apply these principles in C# development?
103. How do you implement data validation and business rules in C#? Discuss approaches like Data Annotations, Fluent Validation, or custom validation logic.
104. Explain the concept of code contracts in C#. How do you use preconditions, postconditions, and invariants to enforce code contracts?
105. How do you handle concurrency and data consistency in multi-threaded applications in C#? Discuss techniques like locks, mutexes, and transactional data access.
106. Describe the concept of asynchronous messaging using message brokers like Apache Kafka or Azure Event Hubs in C#. How does it enable scalable and event-driven architectures?
107. How do you implement automated testing in a C# application? Discuss unit testing frameworks, integration testing, and test-driven development (TDD).
108. Explain the concept of inversion of control (IoC) and dependency injection (DI) in C#. How do you use DI containers like Autofac or Microsoft.Extensions.DependencyInjection?
109. How do you handle and manage application configuration in C#? Discuss approaches like appsettings.json, environment variables, or custom configuration providers.
110. Describe the concept of continuous integration and continuous deployment (CI/CD) in C# development. How do you use tools like Jenkins or Azure DevOps for CI/CD pipelines?

Level 12

111. How do you handle distributed transactions in a C# application? Discuss techniques like two-phase commit and compensating transactions.
112. Explain the concept of reactive programming using frameworks like Reactive Extensions (Rx) in C#. How does it enable event-driven and asynchronous programming?
113. Describe the concept of cloud-native development in C#. How do you build and deploy C# applications in cloud environments like Azure or AWS?
114. How do you implement real-time communication in a C# web application? Discuss technologies like SignalR for WebSocket-based communication.
115. Explain the concept of software design patterns in C#. Discuss commonly used patterns like Factory, Singleton, and Observer, and provide examples of their implementation.
116. How do you implement caching and performance optimization in a C# web application? Discuss techniques like output caching, query caching, and lazy loading.
117. Describe the concept of microservices architecture in C#. How do you design, build, and deploy microservices using frameworks like ASP.NET Core and Docker?
118. How do you handle distributed caching in a C# application? Discuss technologies like Redis or Memcached for distributed caching scenarios.
119. Explain the concept of functional programming in C#. How do you use features like higher-order functions, immutability, and pure functions to write functional code?
120. How do you implement message-driven architectures using message brokers like RabbitMQ or Apache Kafka in C#? Discuss event sourcing and event-driven design patterns.

Level 13

121. How do you handle concurrency and parallelism in C#? Discuss the use of tasks, parallel loops, and parallel LINQ (PLINQ) to improve performance.
122. Explain the concept of asynchronous event handling in C#. How do you use the async/await pattern to handle events asynchronously?
123. Describe the concept of software testing in C#. How do you write unit tests, integration tests, and automated UI tests using frameworks like NUnit or MSTest?
124. How do you work with databases in C#? Discuss different ORM frameworks like Entity Framework and Dapper, and explain their advantages and use cases.
125. Explain the concept of functional programming in C#. How do you use functional features like lambda expressions, higher-order functions, and immutability?
126. Describe the concept of dependency injection (DI) in C#. How do you use DI containers like Autofac or Microsoft.Extensions.DependencyInjection to achieve loose coupling and maintainability?
127. How do you work with asynchronous messaging patterns in C#? Discuss the use of message queues, publish/subscribe models, and message brokers like Azure Service Bus or RabbitMQ.
128. Explain the concept of code analysis and code quality tools in C#. How do you use tools like ReSharper or SonarQube to improve code quality and maintainability?
129. How do you handle data serialization and deserialization in C#? Discuss techniques like JSON serialization, XML serialization, and protocol buffers.
130. Describe the concept of software deployment in C#. How do you package and deploy C# applications using tools like NuGet, Docker, or Azure App Service?

Level 14

131. Explain the concept of garbage collection in C#. How does the garbage collector work, and how can you optimize memory usage and performance?
132. How do you implement data access using ADO.NET in C#? Discuss the use of SqlCommand, SqlDataAdapter, and SqlDataReader for interacting with databases.
133. Describe the concept of unit testing in C#. How do you write effective unit tests using frameworks like xUnit or NUnit?
134. How do you work with asynchronous programming patterns in C#? Discuss the use of Task, async/await, and cancellation tokens for efficient and responsive code.
135. Explain the concept of design patterns in C#. Discuss common design patterns like Factory, Singleton, and Decorator, and provide examples of their usage.
136. How do you implement authentication and authorization in a C# web application? Discuss techniques like forms authentication, claims-based authentication, and role-based authorization.
137. Describe the concept of code versioning and source control in C#. How do you use tools like Git or TFS for managing code changes and collaboration?
138. How do you handle exceptions and errors in C#? Discuss best practices for exception handling, logging, and error reporting.
139. Explain the concept of asynchronous programming using Reactive Extensions (Rx) in C#. How does it simplify event-driven and reactive programming?
140. How do you implement performance monitoring and diagnostics in a C# application? Discuss tools like Performance Counters, ETW, and profiling tools.

Level 15

141. How do you work with distributed caching in a C# application? Discuss technologies like Redis or Memcached and their integration with C# code.
142. Explain the concept of parallel programming in C# using the PLINQ library. How do you parallelize LINQ queries for improved performance?
143. Describe the concept of inversion of control (IoC) containers in C#. How do you use frameworks like Unity or Autofac for dependency injection?
144. How do you implement data validation and error handling in a C# application? Discuss techniques like data annotations, custom validation attributes, and exception handling.
145. Explain the concept of asynchronous web development using C# and ASP.NET. How do you handle asynchronous HTTP requests and responses?
146. How do you implement a RESTful API using C# and ASP.NET Web API? Discuss best practices for designing and securing RESTful APIs.
147. Describe the concept of concurrency control in database systems. How do you handle concurrency issues in C# applications accessing a shared database?
148. How do you implement logging and error tracking in a C# application? Discuss popular logging frameworks like Serilog or NLog.
149. Explain the concept of message-driven architectures in C#. How do you use message brokers like RabbitMQ or Apache Kafka to enable decoupled communication between components?
150. How do you optimize database performance in a C# application? Discuss techniques like indexing, query optimization, and caching.

Level 16

151. Explain the concept of multithreading in C#. How do you create and manage threads, and what are the synchronization mechanisms to ensure thread safety?
152. How do you implement authentication and authorization using ASP.NET Identity in a C# web application? Discuss the role of claims, roles, and authentication middleware.
153. Describe the concept of reflection in C#. How do you use reflection to analyze and manipulate types, properties, and methods at runtime?
154. How do you work with NoSQL databases in C#? Discuss popular NoSQL databases like MongoDB or Redis and their integration with C# code.
155. Explain the concept of dependency injection and inversion of control in C#. How do you implement DI using frameworks like ASP.NET Core’s built-in container or third-party libraries like Ninject?
156. How do you implement caching in a C# application? Discuss techniques like in-memory caching, distributed caching, and cache expiration policies.
157. Describe the concept of event-driven programming in C#. How do you use events and delegates to enable communication between different components of an application?
158. How do you handle distributed tracing and logging in a C# microservices architecture? Discuss tools like Zipkin or Jaeger for distributed tracing and centralized log aggregation.
159. Explain the concept of code-first and database-first approaches in Entity Framework. How do you use migrations to manage database schema changes?
160. How do you implement message queueing and processing in a C# application? Discuss frameworks like MassTransit or NServiceBus for reliable and scalable message-based communication.

Level 17

161. Explain the concept of serialization in C#. How do you serialize and deserialize objects to and from XML, JSON, or binary formats?
162. How do you handle file and directory operations in C#? Discuss techniques for file I/O, directory traversal, and file system monitoring.
163. Describe the concept of asynchronous programming using the Task-based Asynchronous Pattern (TAP) in C#. How do you write and consume asynchronous methods?
164. How do you work with HTTP-based APIs in C#? Discuss techniques for making HTTP requests, handling responses, and working with RESTful APIs.
165. Explain the concept of object-relational mapping (ORM) in C#. How do you use an ORM framework like Entity Framework to interact with a database?
166. How do you implement data encryption and decryption in C#? Discuss symmetric and asymmetric encryption algorithms and their usage.
167. Describe the concept of dependency inversion in C#. How do you design and implement loosely coupled and maintainable code using interfaces and DI?
168. How do you handle performance profiling and optimization in a C# application? Discuss tools like Visual Studio Profiler and strategies for identifying and resolving performance bottlenecks.
169. Explain the concept of code contracts in C#. How do you use preconditions, postconditions, and invariants to ensure code correctness and robustness?
170. How do you implement background processing and scheduling in a C# application? Discuss libraries like Hangfire or Quartz.NET for task scheduling and execution.

Level 18

171. Explain the concept of reflection in C#. How do you use reflection to inspect types, access members dynamically, and invoke methods at runtime?
172. How do you implement caching in a C# web application? Discuss techniques like in-memory caching, output caching, and distributed caching using frameworks like Redis or MemoryCache.
173. Describe the concept of cross-platform development using Xamarin in C#. How do you build mobile applications for iOS and Android using a shared codebase?
174. How do you handle data concurrency and transactions in C#? Discuss techniques like optimistic concurrency control and the use of transaction scopes.
175. Explain the concept of message queues in C#. How do you use message queuing systems like RabbitMQ or Azure Service Bus for reliable and asynchronous communication?
176. How do you implement localization and globalization in a C# application? Discuss techniques for supporting multiple languages and cultures.
177. Describe the concept of continuous integration and continuous deployment (CI/CD) in C# development. How do you use tools like Jenkins or Azure DevOps for automating the build, test, and deployment processes?
178. How do you handle security vulnerabilities like cross-site scripting (XSS) or SQL injection in a C# web application? Discuss techniques for input validation, output encoding, and parameterized queries.
179. Explain the concept of code reusability in C#. How do you use inheritance, interfaces, and class libraries to promote code reuse and modularity?
180. How do you work with third-party APIs and web services in C#? Discuss techniques for making HTTP requests, handling authentication, and parsing response data.

Level 19

181. How do you work with data structures and algorithms in C#? Discuss common data structures like arrays, linked lists, and hash tables, as well as algorithmic concepts like sorting and searching.
182. Explain the concept of parallel computing in C#. How do you leverage multi-core processors using the Task Parallel Library (TPL) and Parallel LINQ (PLINQ)?
183. Describe the concept of machine learning in C#. How do you use libraries like ML.NET or TensorFlow.NET to implement machine learning models and algorithms?
184. How do you implement secure communication and encryption in a C# application? Discuss techniques like SSL/TLS, public-key encryption, and secure socket layers.
185. Explain the concept of reactive programming in C#. How do you use reactive frameworks like Rx.NET or ReactiveUI to handle asynchronous and event-driven scenarios?
186. Describe the concept of containerization using Docker in C# development. How do you package, deploy, and manage C# applications using containers?
187. How do you implement background processing and task scheduling in a C# application? Discuss techniques like async/await, background workers, and task schedulers.
188. Explain the concept of performance tuning and optimization in C#. How do you analyze performance bottlenecks, optimize code, and improve application responsiveness?
189. How do you handle data storage and retrieval using Entity Framework Core in C#? Discuss techniques for working with databases, querying data, and managing migrations.
190. Describe the concept of message-driven architectures in C#. How do you use messaging frameworks like Apache Kafka or Azure Service Bus for asynchronous and decoupled communication?

Level 20

191. How do you implement real-time communication in a C# application? Discuss technologies like WebSocket and SignalR for enabling bidirectional communication between the client and server.
192. Explain the concept of code refactoring in C#. How do you identify code smells and apply refactoring techniques to improve code quality and maintainability?
193. Describe the concept of cloud computing and C# development. How do you leverage cloud platforms like Azure or AWS to build scalable and resilient applications?
194. How do you implement authentication and authorization in a C# API? Discuss techniques like JSON Web Tokens (JWT) and OAuth for securing API endpoints.
195. Explain the concept of software architectural patterns in C#. Discuss patterns like MVC, MVVM, and hexagonal architecture, and provide examples of their usage.
196. How do you work with big data processing in C#? Discuss frameworks like Apache Spark or Hadoop for distributed data processing and analytics.
197. Describe the concept of test-driven development (TDD) in C#. How do you write unit tests first and use them to drive the development process?
198. How do you implement search functionality in a C# application? Discuss techniques like full-text search, indexing, and integration with search engines like Elasticsearch or Solr.
199. Explain the concept of serverless computing and C# development. How do you build serverless applications using platforms like Azure Functions or AWS Lambda?
200. How do you ensure code quality and maintainability in a C# project? Discuss techniques like code reviews, static code analysis, and automated testing.