Top C# Interview Questions and Answers

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C# is a simple, modern, general purpose programming language. It is an object oriented programming language developed by Microsoft. It is a safe and managed language that is compiled by .NET framework to generate Microsoft intermediate language.

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You would always know C being the procedural language while C# is a more object-oriented language. The biggest difference is that C# supports automatic garbage collection by Common Language Runtime (CLR) while C does not. C# primarily needs a .NET framework to execute while C is a platform-agnostic language.

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The Array which comprises elements of type array is called Jagged Array. The elements in Jagged Arrays can be of various dimensions and sizes.

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When an argument is passed as a ref, it must be initialized before it can be passed to the method. An out parameter, on the other hand, need not to be initialized before passing to a method.

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The ‘using’ statement can be used in order to obtain a resource for processing before automatically disposing it when execution is completed.

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Continue statement – Used in jumping over a particular iteration and getting into the next iteration of the loop.

Break statement – Used to skip the next statements of the current iteration and come out of the loop.

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Steps of code compilation in C# include –

• Source code compilation in managed code.
• Newly created code is clubbed with assembly code.
• The Common Language Runtime (CLR) is loaded.
• Assembly execution is done through CLR.

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The various methods of passing parameters in a method include –

• Output parameters: Lets the method return more than one value.
• Value parameters: The formal value copies and stores the value of the actual argument, which enables the manipulation of the formal parameter without affecting the value of the actual parameter.
• Reference parameters: The memory address of the actual parameter is stored in the formal argument, which means any change to the formal parameter would reflect on the actual argument too.

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The following are the advantages of C# –

• C# is component-oriented.
• It is an object-oriented language.
• The syntax is really easy to grasp.
• It is easier to learn.
• C# is part of the framework called .NET

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The C# access modifiers are –

Private Access Modifier – A private attribute or method is one that can only be accessed from within the class.

Public Access Modifier – When an attribute or method is declared public, it can be accessed from anywhere in the code.

Internal Access Modifier – When a property or method is defined as internal, it can only be accessible from the current assembly point of that class.

Protected Access Modifier – When a user declares a method or attribute as protected, it can only be accessed by members of that class and those who inherit it.

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It’s a type of class whose objects can’t be instantiated, and it’s signified by the term ‘abstract’. It consists of a methodology or a single approach.

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A partial class effectively breaks a class’s definition into various classes in the same or other source code files. A class definition can be written in numerous files, but it is compiled as a single class at runtime, and when a class is formed, all methods from all source files can be accessed using the same object. The keyword ‘partial’ denotes this.

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During the time of compilation, constant variables are declared as well as initialized. It’s not possible to change this particular value later. On the other hand, read-only is used after a value is assigned at run time.

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Variables or methods that are Protected Internal can be accessed within the same assembly as well as from the classes which have been derived from the parent class.

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System.String is absolute. When a string variable’s value is modified, a new memory is assigned to the new value. The previous memory allocation gets released. System.StringBuilder, on the other hand, is designed so it can have a mutable string in which a plethora of operations can be performed without the need for allocation of a separate memory location for the string that has been modified.

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In the Clone() method, a new array object is created, with all the original Array elements using the CopyTo() method. Essentially, all the elements present in the existing array get copied into another existing array.

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Lock statement is used to ensure that one thread doesn’t enter a critical section of code while another thread is in the critical section. If another thread attempts to enter a locked code it will wait, block, until the object is released.

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If you want to transport an object through network then you have to convert the object into a stream of bytes. The process of converting an object into a stream of bytes is called serialization.

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Boxing in C#

• The process of Converting a Value Type (char, int, etc.) to a Reference Type(object) is called Boxing.
• Boxing is an implicit conversion process in which object type (supertype) is used.
• The Value type is always stored in Stack. The Referenced Type is stored in Heap.

Unboxing in C#

• The process of converting the reference type into the value type is known as Unboxing.
• It is an explicit conversion process.

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Method overloading essentially is creating multiple methods with the same name and unique signatures with the same class. When you compile, the compiler makes use of overload resolution to determine the specific method which will be invoked.