Are you gearing up for a C# programming interview? Whether you’re a recent graduate or transitioning into a software development career, mastering the basics of C# is crucial. To help you prepare, here are the top 20 C# interview questions along with concise answers tailored for freshers.
1. What is C#?
C# is a modern, object-oriented programming language developed by Microsoft. It is designed for building a wide range of applications that run on the .NET Framework or .NET Core.
2. Explain the difference between == and Equals() method in C#.
- == operator compares value equality for value types and reference equality for reference types.
- Equals() method is used to compare the contents or values of two objects. It can be overridden in derived classes.
3. What are the basic data types in C#?
C# supports numeric types (int, float, double, decimal), boolean type (bool), character type (char), and string type (string).
4. What are access modifiers in C#?
Access modifiers control the visibility and accessibility of classes, methods, and other members. Common modifiers include public, private, protected, internal, and protected internal.
5. Explain the difference between ref and out parameters in C#.
- ref parameters must be initialized before being passed to a method. Changes made inside the method are reflected outside.
- out parameters do not require initialization and must be assigned a value inside the method.
6. What is a namespace in C#?
A namespace is a way to organize and group related classes, interfaces, enums, and structs. It helps avoid naming conflicts and improves code readability.
7. What is inheritance in C#?
Inheritance allows a class (derived class) to inherit properties and behavior from another class (base class). It promotes code reusability and supports the “is-a” relationship.
8. What is method overloading?
Method overloading allows defining multiple methods with the same name but different parameters in the same class. The compiler determines which method to call based on the arguments.
9. What is method overriding?
Method overriding occurs when a derived class provides a specific implementation of a method that is already defined in the base class. It is achieved using the override keyword.
10. Explain the difference between List and Array in C#.
- List<T> is a generic collection that can dynamically resize itself. It offers more flexibility and functionality compared to arrays.
- Arrays have a fixed size and require specifying the size during declaration.
11. What is the this keyword in C#?
The this keyword refers to the current instance of a class or struct. It is used to access members of the current object and to differentiate between instance variables and parameters with the same name.
12. What are properties in C#?
Properties provide a way to encapsulate fields in a class, allowing controlled access to them. They consist of a get accessor (getter) and optionally a set accessor (setter).
13. What is the difference between StringBuilder and String in C#?
- StringBuilder is mutable and efficient for string manipulations (e.g., appending, inserting).
- String is immutable and creates a new object for each modification, which can be inefficient for frequent operations.
14. What is an interface in C#?
An interface defines a contract that classes can implement. It contains method signatures, properties, events, or indexers without providing implementation details.
15. What is a delegate in C#?
A delegate is a type that represents references to methods with a specific signature. It allows invoking methods indirectly and supports callback mechanisms.
16. Explain the concept of exception handling in C#.
Exception handling is used to handle runtime errors or exceptional conditions in a program. It involves try-catch blocks to catch and handle exceptions gracefully.
17. What is LINQ (Language Integrated Query)?
LINQ is a set of language extensions in C# that allows querying data from various data sources (e.g., collections, databases) using a SQL-like syntax within C# code.
18. What is garbage collection in C#?
Garbage collection is an automatic memory management process in C# that identifies and removes unused objects from memory, preventing memory leaks and managing memory efficiently.
19. What is asynchronous programming in C#?
Asynchronous programming allows writing code that can execute concurrently, improving responsiveness and scalability. It is achieved using async and await keywords with tasks.
20. What are attributes in C#?
Attributes provide metadata about types, members, or assemblies in C#. They are used for adding information, defining behavior, or controlling runtime aspects of code.
Mastering these C# interview questions and concepts can greatly enhance your confidence and readiness for C# programming interviews as a fresher. Practice coding examples and explore real-world scenarios to deepen your understanding. Good luck!
