C# Questions and Answers for Viva

Answer-1: C# is a modern, object-oriented programming language developed by Microsoft as part of the .NET platform.

Answer-2: Key features include object-oriented programming, strong typing, garbage collection, and support for LINQ.

Answer-3: The CLR is the runtime environment in the .NET Framework that handles code execution, memory management, and security.

Answer-4: struct is a value type stored in the stack; class is a reference type stored in the heap.

Answer-5: Managed code is executed under the supervision of the CLR, which provides memory management and security.

Answer-6: An assembly is a compiled code library used in .NET, consisting of DLL or EXE files.

Answer-7: Array is fixed in size and type-safe; ArrayList can grow dynamically and holds objects of any type.

Answer-8: Value types store data directly, while reference types store references to the data's memory location.

Answer-9: == compares object references or values; .Equals() checks for content equality.

Answer-10: The using keyword manages namespaces and ensures proper disposal of unmanaged resources.

Answer-11: A delegate is a type-safe function pointer used for callback methods and event handling.

Answer-12: Events are notifications sent by an object to signal that something has occurred.

Answer-13: An abstract class can have implemented methods; an interface cannot have any implementation (until C# 8.0).

Answer-14: Polymorphism allows methods to have different implementations based on the context (overriding and overloading).

Answer-15: Encapsulation is bundling data and methods in a class and restricting access to its details.

Answer-16: Inheritance allows a class to acquire properties and methods from another class.

Answer-17: The static keyword makes members belong to the class rather than an instance of the class.

Answer-18: sealed prevents a class from being inherited.

Answer-19: const is a compile-time constant; readonly is a runtime constant.

Answer-20: Nullable types allow value types to hold null. Example: int? x = null;.

Answer-21: Generics allow the creation of type-safe data structures and methods without committing to a specific data type.

Answer-22: LINQ (Language Integrated Query) allows querying collections and databases in a consistent way.

Answer-23: IEnumerable is for in-memory queries; IQueryable allows remote queries like databases.

Answer-24: try-catch is used to handle exceptions by executing alternative code when an error occurs.

Answer-25: The finally block executes code after a try-catch block, regardless of whether an exception was thrown.

Answer-26: throw preserves the original exception stack trace; throw ex overwrites it.

Answer-27: Garbage collection automatically manages memory by removing objects no longer in use.

Answer-28: Dispose() is called explicitly; Finalize() is called by the garbage collector.

Answer-29: A thread is a lightweight process that allows concurrent execution of code.

Answer-30: async marks a method as asynchronous, and await pauses the execution until the task completes.

Answer-31: Extension methods allow adding new methods to existing types without modifying them.

Answer-32: ref requires initialization before use; out does not.

Answer-33: Properties are special methods that encapsulate data access (getters and setters).

Answer-34: is checks type compatibility; as performs type conversion and returns null if it fails.

Answer-35: A partial class allows splitting a class's implementation across multiple files.

Answer-36: A tuple is a data structure for storing multiple values of different types.

Answer-37: Indexers allow objects to be indexed like arrays.

Answer-38: The stack is for static memory allocation; the heap is for dynamic memory allocation.

Answer-39: The lock keyword ensures that a block of code is executed by only one thread at a time.

Answer-40: Attributes provide metadata about types, methods, and properties.

Answer-41: Reflection is used to inspect and manipulate metadata at runtime.

Answer-42: Shallow copy duplicates references; deep copy duplicates the actual objects.

Answer-43: Nullable types allow variables to hold null values. Example: int? num = null;.

Answer-44: String is immutable; StringBuilder is mutable and allows modifying strings efficiently.

Answer-45: Access modifiers include public, private, protected, internal, and combinations like protected internal.

Answer-46: An abstract class can have implemented methods; interfaces cannot until C# 8.0.

Answer-47: The singleton pattern restricts a class to a single instance and provides a global access point.

Answer-48: The base keyword accesses methods and properties of a parent class from a child class.

Answer-49: Early binding happens at compile time; late binding happens at runtime.

Answer-50: Use try-catch blocks and optionally finally to handle exceptions.