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100 common C# interview questions
LISTEN TO THE C# INTERVIEW FAQs LIKE AN AUDIOBOOK
C# is a popular programming language developed by Microsoft, widely used for building various applications. If you’re preparing for a C# interview, this guide is here to help you get ready. We’ve compiled a list of 100 common C# interview questions along with clear and straightforward answers to assist you in your preparation.
In this guide, you’ll find questions covering C# Fundamentals, Object-Oriented Programming Concepts, .NET Framework, Data Structures and Algorithms, Exception Handling, Design Patterns, etc.
Whether you’re new to C# or looking to brush up your skills, these questions and answers are designed to help you feel more confident and prepared for your interview. Let’s get started!
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A generic method in C# is a method that can operate on multiple data types without duplication. It uses type parameters, which are specified when the method is called. Generic methods are useful for creating reusable algorithms and functions.
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A property in C# is a member of a class that provides controlled access to a private field. It consists of ‘get’ and ‘set’ accessors, allowing the value of the property to be retrieved or modified. Properties can have additional access modifiers and help encapsulate the internal implementation of a class.
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A get accessor in C# is employed to retrieve the value of a property. It is defined using the ‘get’ keyword and can include additional code for calculating the property’s value if needed. It is commonly used to enable controlled access to private data members.
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A set accessor in C# is utilized to assign a value to a property. It is defined using the ‘set’ keyword and can contain code for validating the assigned value or performing other operations. It is often used to provide controlled access to private data members.
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In C#, an event serves as a mechanism for one object to notify other objects about a specific occurrence. It is declared using the ‘event’ keyword and is typically associated with a delegate type. Other objects can subscribe to the event and receive notifications when it is raised. Events are commonly used in GUI programming to respond to user actions such as button clicks or mouse movements.
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In C#, a collection refers to a group of related objects. It is represented by a class that facilitates the storage and manipulation of a set of interconnected objects. Collections offer programmers an efficient and organized way to work with groups of objects.
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In C#, an array is a data structure that stores a fixed-size sequential collection of elements of the same type. It is a group of elements, where each element is recognized by an index or a key.
Arrays can be multidimensional, meaning they can have more than one index.
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A dictionary in C# is a collection that stores key-value pairs. It resembles an array but uses keys instead of integers for indexing. Keys in a dictionary must be unique, while values can be duplicated. Dictionaries provide an efficient way to retrieve values based on their associated keys.
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A list in C# is a collection that maintains an ordered sequence of elements. It resembles an array but can dynamically grow or shrink as elements are added or removed. Lists can store elements of any data type and provide convenient methods for manipulating the collection.
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A tuple in C# is a data structure that holds a fixed number of elements, each of which can have a different type. It offers a lightweight means of combining multiple values into a single object. Tuples are commonly used when a method needs to return multiple values.
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In C#, a value type is a type that directly stores its value in memory. Examples of value types include int, float, bool, and struct. When passed as parameters or assigned to variables, value types are copied.
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A stack in C# is a data structure that follows the Last-In-First-Out (LIFO) principle. The most recently added element is the first one to be removed.
Common operations performed on a stack in C# include:
- Push: Adding an element to the top of the stack
- Pop: Removing the top element from the stack
- Peek: Returning the top element of the stack without removing it
- Count: Returning the number of elements in the stack
- Clear: Removing all elements from the stack
Stacks are useful in various programming scenarios such as expression parsing, recursive algorithms, and implementing undo-redo functionality.
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A queue in C# is a data structure that operates on the principle of First-In-First-Out (FIFO). This means that the element added first to the queue is the first one to be removed.
In C#, common operations on a queue include;
- Enqueue: Adding an element to the back of the queue
- Dequeue: Removing the front element from the queue
- Peek: Returning the front element of the queue without removing it
- Count: Returning the number of elements in the queue
- Clear: Removing all elements from the queue
Queues are commonly used in C# for tasks such as task scheduling, message queue implementation, and breadth-first search algorithms.
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A HashSet in C# is a collection that stores unique elements. It leverages hashing techniques to achieve efficient performance for operations like adding, removing, and checking the presence of elements. The HashSet class is part of the System.Collections.Generic namespace in C#.
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In C#, an IDictionary is an interface that represents a collection of key-value pairs. It provides efficient lookup of values based on their associated keys. The IDictionary interface is included in the System.Collections.Generic namespace in C#.
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Microsoft offers several notable IDEs for C# development. These include MonoDevelop, Visual Studio Code (VS Code), Browxy, Visual Studio Express (VSE), and Visual Web Developer (VWD).
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C# encompasses several significant features, including:
- C# is a safely typed and managed language.
- C# supports object-oriented programming paradigms
- C# is designed to be cross-platform
- C# is a versatile language suitable for a wide range of application development scenarios
- C# facilitates the creation and destruction of objects through constructors and destructors.
- C# is an integral part of the .NET framework
- C# is an easy-to-learn and easy-to-grasp language
- C# supports structured programming principles
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In C#, managed code refers to code that is executed within the context of the Common Language Runtime (CLR). Managed code relies on the services provided by the .NET platform, such as memory management and security.
Code executed by a runtime programme outside of the .NET platform is considered unmanaged code. Security, Memory, and other activities related to execution are responsible to be handled by the application’s runtime.
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Once the try and catch blocks have been finished, the finalize block is called as it is used for exception handling. Whether the exception has been captured or not, this block of code is run. In general, the code is cleaner in this block.
Just before garbage collection, the finalize method is called. The chief priorities of the finalize method are to clean up unmanaged code, which gets automatically triggered whenever an instance is not re-called.
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The Dispose() method is used when an object needs to release any unmanaged resources it holds. On the other hand, the Finalize() method does not guarantee the garbage collection of an object, even though it serves a similar purpose.