Top 20 Basic Level C# Interview Questions with Answers and Explanation

1- What is C#?

C# (Pronunciation: See Sharp) is a new language mostly for coding, at the heart of many Microsoft platform-based projects. This language applies to many application developments: web, desktop, mobile, and games, for example.

Explanation: C# has been developed with usability, speed, and scalability as primary objectives. This is the principal reason why the C# language is considerably applied in corporate areas.

2- What is an object in C#?

An object is a class instance. One can describe it as an object created with the new keyword; its meaning is the specific entity that possesses some state attributes and some behavior methods.

Explanation: The C# language supports object-oriented programming concepts; the concept of classes must be utilized to represent real-world concepts. Thus, objects named myCar and your Car can be held within a car class with their respective property states.

3. What is a class in C#?

A class is taken to be the abstract class from which objects are created which could act as a model or design. It also includes the properties, the methods and event handlers of its objects.

Explanation: A class is one of the basic concepts utilized in an object-oriented programming structure. For instance, a class called Person may have a Name and an Age as attributes and a Walk() and Talk() as behaviors.

4. What is C# Inheritance?

C# Inheritance is the reusability of classes whereby a class, known as the child or derived class, inherits the attributes as well as characteristics, such as methods of another class, which is called a parent or base class.

Explanation: This is how you will reuse existing code. For example, you may have Animal class and Dog which inherits from this class inheriting its typical features like attributes like Age or methods like Eat() without any change in their implementation.

5. What do you mean by term 'polymorphism' used in C# Language?  

Polymorphism is the ability to take many forms. Basically, in C#, one can have different implementations of methods called based on the object making the call. 

Explanation: Polymorphism is implemented by using method overriding and interfaces. Hence, a single interface can be defined, but there can be many ways of defining the functionality.

6. What is meant by encapsulation in C# programming? 

Encapsulation refers to the packaging of data, that is, attributes, and methods or functions related to data into one class. It also hides from the user knowledge about certain parts of the system. 

Explanation: With the help of public methods, it aids in giving restricted access to encase the battered state of the object so that its consistency can be maintained.

7. What is an interface in C#?

An interface is a declaration that specifies a set of methods which any class is expected to implement. It has pure method declarations only, without any definitions. Classes implementing the interface provide the definitions of those methods too. 

Explanation: Interfaces help reach a certain level of behavior or structure in a class and help encourage multiple class inheritance, which is not allowed in C#.

8. What is a constructor in C#?

A constructor is a class member function which gets automatically called upon the creation of an object. The main aim of a constructor is to set attribute values of the given object. 

Explanation: Constructors can include non-optional and optional arguments for values to be passed to the object while it is initialized during creation. In c# overloaded constructors are also allowed.

9. What's the destructor in C#? 

Destructors are styles that are invoked while an object is going out of compass and being destroyed, and they're employed for the task of remittal operations previous to the object being reclaimed by the scrap collector. 

Explanation 

does n't make extensive use of destructors. rather, C# provides the scrap collector to handle the memory, still in some cases, a destructor can be used to free up unmanaged coffers. 

10. What's the difference between class and structure in C#? 

Major difference classes are reference types and structs are value types. Classes can be made to be allocated on the mound whereas structs are allowed to be allocated on the mound. 

Explanation: Structs are used for small simple objects. Classes are applied for more complex objects that might bear geste as well as dynamic memory operation. 

11. What's an abstract class in C#? 

An abstract class is a class which can not be expressed directly. The below system can also have perpetration and non-abstract styles. 

 

Explanation: Abstract classes are the base classes from where other classes extend and give partial perpetration that the deduced classes must fill in. 

 12. What's the difference between an abstract and virtual system in C#? 

 A virtual system can have dereliction perpetration and, at the same time is allowed for override; an abstract system has no perpetration and must be hoofed in a secondary class. 

Explanation :  Virtual styles The capability of any derivations to stamp dereliction perpetration or to use dereliction perpetration, whereas abstract styles apply derivate perpetration. 

13. What does system overloading represent in C#? 

System Overloading is that point that allows having a different number or type of parameters with the same system name. 

Explanation : Overloading makes styles more flexible and easier to use without taking the names of different styles to perform analogous operation. 

14. What is method overriding in C#?

The derived class gets a chance to implement its own version of the method already defined in its base class through method overriding.

Explanation:

Method inside the base class should be declared as virtual and in derived class it uses override keyword in order to override a method.

 

15. What is delegate in C#?

A delegate is a type that holds references to methods. Delegates are of great use while passing methods as arguments of other methods.

Explanation: Delegates are applied in designing extensible and flexible applications. It can be used in event-driven programming, wherein the delegate points to a method, which is called later.

16. What is any event in C#?

An event is a message that an object sends to indicate that something interesting has occurred. Because events in C# are based on delegates, experiences with events most commonly occur in user-interface programs.

Events allow classes or objects to notify other classes or objects that an interesting thing has happened. One of the most common scenarios for applying event handling is a program's reaction to a button click in a GUI application .

17. What is exception handling in C#?

Exception handling is a mechanism used during runtime to deal with the runtime errors using try, catch, finally and throw blocks.

Explanation: It maintains the continuation of a program due to the fact that once the exceptions are caught and all proper actions are performed; it doesn't allow the application to crash abruptly.

18. What is the difference between throw and throw ex in C#?

Throw changes the original exception without losing its stack trace, whereas throw ex throws an exception with a new stack trace.

Explanation : It should also be kept on the stack trace while debugging. The throw statement holds the stack trace which specifies where the actual error has been encountered.

19. What is the using statement in C#?

The using statement is used to automatically release objects that implement IDisposable interface, such as files or database connections that are no longer in use.

Explanation: This is considered to be an important aspect of resource management since resources are released in the right as well as proper way.

20. What are access modifiers in C#?

Access modifiers Define the access or visibility of class and its members. The most common ones are public, private, protected, and internal.

Explanation: They help in showing encapsulation of data and how data members of a class can be accessed or modified from outside the class