c# interview
TRANSCRIPT
C# interview questions and answers
1. What’s the advantage of
using
System.Text.StringBuilder
over
System.String? StringBuilder
is more efficient in the cases,
where a lot of manipulation is
done to the text. Strings are
immutable, so each time it’s
being operated on, a new
instance is created.
2. Can you store multiple data
types in System.Array? No.
3. What’s the difference
between the
System.Array.CopyTo() and
System.Array.Clone()? The
first one performs a deep copy
of the array, the second one is
shallow.
4. How can you sort the
elements of the array in
descending order? By calling
Sort() and then Reverse()
methods.
5. What’s the .NET datatype
that allows the retrieval of
data by a unique key?
HashTable.
6. What’s class SortedList
underneath? A sorted
HashTable.
7. Will finally block get
executed if the exception
had not occurred? Yes.
8. What’s the C# equivalent of
C++ catch (…), which was a
catch-all statement for any
possible exception? A catch
block that catches the
exception of type
System.Exception. You can also
omit the parameter data type in
this case and just write catch
{}.
9. Can multiple catch blocks be
executed? No, once the proper
catch code fires off, the control
is transferred to the finally
block (if there are any), and
then whatever follows the
finally block.
10.Why is it a bad idea to throw
your own exceptions? Well, if
at that point you know that an
error has occurred, then why
not write the proper code to
handle that error instead of
passing a new Exception object
to the catch block? Throwing
your own exceptions signifies
some design flaws in the
project.
11.What’s a delegate? A delegate
object encapsulates a reference
to a method. In C++ they were
referred to as function pointers.
12.What’s a multicast
delegate? It’s a delegate that
points to and eventually fires
off several methods.
13.How’s the DLL Hell problem
solved in .NET? Assembly
versioning allows the
application to specify not only
the library it needs to run
(which was available under
Win32), but also the version of
the assembly.
14.What are the ways to deploy
an assembly? An MSI
installer, a CAB archive, and
XCOPY command.
15.What’s a satellite
assembly? When you write a
multilingual or multi-cultural
application in .NET, and want
to distribute the core
application separately from the
localized modules, the localized
assemblies that modify the core
application are called satellite
assemblies.
16.What namespaces are
necessary to create a
localized application?
System.Globalization,
System.Resources.
17.What’s the difference
between // comments, /* */
comments and ///
comments? Single-line, multi-
line and XML documentation
comments.
18.How do you generate
documentation from the C#
file commented properly
with a command-line
compiler? Compile it with a
/doc switch.
19.What’s the difference
between <c> and <code>
XML documentation
tag? Single line code example
and multiple-line code example.
20.Is XML case-sensitive? Yes,
so <Student> and <student>
are different elements.
21.What debugging tools come
with the .NET SDK? CorDBG
– command-line debugger, and
DbgCLR – graphic debugger.
Visual Studio .NET uses the
DbgCLR. To use CorDbg, you
must compile the original C#
file using the /debug switch.
22.What does the This window
show in the debugger? It
points to the object that’s
pointed to by this reference.
Object’s instance data is shown.
23.What does assert() do? In
debug compilation, assert takes
in a Boolean condition as a
parameter, and shows the error
dialog if the condition is false.
The program proceeds without
any interruption if the condition
is true.
24.What’s the difference
between the Debug class and
Trace class? Documentation
looks the same. Use Debug
class for debug builds, use
Trace class for both debug and
release builds.
25.Why are there five tracing
levels in
System.Diagnostics.TraceSw
itcher? The tracing dumps can
be quite verbose and for some
applications that are constantly
running you run the risk of
overloading the machine and
the hard drive there. Five levels
range from None to Verbose,
allowing to fine-tune the
tracing activities.
26.Where is the output of
TextWriterTraceListener
redirected? To the Console or
a text file depending on the
parameter passed to the
constructor.
27.How do you debug an
ASP.NET Web
application? Attach the
aspnet_wp.exe process to the
DbgClr debugger.
28.What are three test cases
you should go through in
unit testing? Positive test
cases (correct data, correct
output), negative test cases
(broken or missing data, proper
handling), exception test cases
(exceptions are thrown and
caught properly).
29.Can you change the value of
a variable while debugging a
C# application? Yes, if you
are debugging via Visual
Studio.NET, just go to
Immediate window.
30.Explain the three services
model (three-tier
application). Presentation
(UI), business (logic and
underlying code) and data
(from storage or other sources).
31.What are advantages and
disadvantages of Microsoft-
provided data provider
classes in
ADO.NET? SQLServer.NET
data provider is high-speed and
robust, but requires SQL
Server license purchased from
Microsoft. OLE-DB.NET is
universal for accessing other
sources, like Oracle, DB2,
Microsoft Access and Informix,
but it’s a .NET layer on top of
OLE layer, so not the fastest
thing in the world. ODBC.NET
is a deprecated layer provided
for backward compatibility to
ODBC engines.
32.What’s the role of the
DataReader class in
ADO.NET connections? It
returns a read-only dataset
from the data source when the
command is executed.
33.What is the wildcard
character in SQL? Let’s say
you want to query database
with LIKE for all employees
whose name starts with
La. The wildcard character is
%, the proper query with LIKE
would involve ‘La%’.
34.Explain ACID rule of thumb
for transactions. Transaction
must be Atomic (it is one unit of
work and does not dependent
on previous and following
transactions), Consistent (data
is either committed or roll
back, no “in-between” case
where something has been
updated and something hasn’t),
Isolated (no transaction sees
the intermediate results of the
current transaction), Durable
(the values persist if the data
had been committed even if the
system crashes right after).
35.What connections does
Microsoft SQL Server
support? Windows
Authentication (via Active
Directory) and SQL Server
authentication (via Microsoft
SQL Server username and
passwords).
36.Which one is trusted and
which one is
untrusted? Windows
Authentication is trusted
because the username and
password are checked with the
Active Directory, the SQL
Server authentication is
untrusted, since SQL Server is
the only verifier participating in
the transaction.
37.Why would you use
untrusted verificaion? Web
Services might use it, as well as
non-Windows applications.
38.What does the parameter
Initial Catalog define inside
Connection String?The
database name to connect to.
39.What’s the data provider
name to connect to Access
database? Microsoft.Access.
40.What does Dispose method
do with the connection
object? Deletes it from the
memory.
41.What is a pre-requisite for
connection pooling? Multiple
processes must agree that they
will share the same connection,
where every parameter is the
same, including the security
settings.
1. Which of the following can be used to add alternating color scheme in a Repeater control?Answer: AlternatingItemTemplate
7. The .NET Framework provides a runtime environment calledAnswer: CLR8. If one has two different web form controls in a application and if one wanted to know whether the values in the above two different web form control match what control must be used?Answer: CompareValidator9. The actual work process of ASP.NET is taken care byAnswer: aspnet_wp.exe10. Give One word: Common type system is built into which of the following:Answer: CLR13. Find the term: The .NET framework which provides automatic memory management using a technique calledAnswer: Garbage Collection
1. The namespace within the Microsoft .NET framework which provides the functionality to implement transaction processing isAnswer: System.EnterpriseServices2. What is the base class from which all Web forms inherit?Answer: Page Class3. In ASP.NET the sessions can be dumped by usingAnswer: Session.Abandon4. Suppose one wants to modify a SOAP message in a SOAP extension then how this can be achieved. Choose the correct option from below:Answer: One must override the method ReceiveMessage5. Which method do you invoke on the DataAdapter control to load
your generated dataset with data?)Answer: Fill( )6. Which of the following is TRUE about Windows Authentication in ASP.NET?Answer: Automatically determines role membership7. The technique that allow code to make function calls to .NET applications on other processes and on other machines isAnswer: .NET Remoting8. The type of code found in Code-Behind class isAnswer: Server-side code9. Which of the following transfer execution directly to another page?Answer: Server.Transfer10. In ASP.NET in form page the object which contains the user name isAnswer: Page.User.Identity11. Suppose a .NET programmer wants to convert an object into a stream of bytes then the process is calledAnswer: Serialization12. What tags one need to add within the asp:datagrid tags to bind columns manually?Answer: Set AutoGenerateColumns Property to false on the datagrid tag13. In my .NET Framework I have threads. Which of the following denote the possible priority level for the threads?Answer: All the Above14. GIVE ONE WORD: In .NET the operation of reading metadata and using its contents is known asAnswer: Reflection
15. Which of the following allow writing formatted output?Answer: Response.Output.Write()16. How many classes can a single .NET DLL contain?Answer: Many17. WSDL stands forAnswer: Web Services Description Language
An organization has developed a web service in which the values of the forms are validated using ASP.NET application. Suppose this web service is got and used by a customer then in such a scenario
which of the following is TRUE
The customer can run on any
platform.”*
Which of the following denote page code model in ASP.NET?
single-file
code-behind
Both A) and B)*
In ASP.NET if one wants to maintain session then which of the following is used?
In-process storage
Session State Service
Microsoft SQL Server
All the Above*
There is a requirement as follows:A client side already has 25 COM objects and if the requirement is to add a 26th function that must exists only for .NET object without affecting the existing one how to achieve the above?
By CCW* By RCW
None of the Above
In ASP.NET if one wants to set the focus on a particular control
Call FOCUS method*
1. On which of the operating system below ASP.NET can run?Answer: Both A) and B)2. There is a requirement as follows:A client side already has 25 COM objects and if the requirement is to add a 26th function that must exists only for .NET object without affecting the existing one how to achieve the above?
Answer: By CCW
3. In ASP.NET if one uses Windows authentication the current request attaches an object called asAnswer: WindowsPrincipal
4. In ASP.NET if you want to allows page developers a way to specify static connections in a content page then the class used is
Answer: ProxyWebPartManager
5. The GridView control in ASP.NET has which of the following featuresAnswer: Both A) and B)6. To set page title dynamically in ASP.NET which of the following is used?Answer: < head > section
7. the forms are validated using ASP.NET application. Suppose this web service is got and used by a customer then in such a scenario which of the following is TRUE
Answer: The customer can run on any platform.8. Give one word: What model does ASP.NET request processing is based onAnswer: Pipeline9. ASP.NET separates the HTML output from program logic using a feature named asAnswer: Code-behind
3. In ASP.NET application the Global.asax file lie in which directoryAnswer: ROOT4. In ASP.NET page framework an automatic way to associate page events and methods isAnswer: AutoEventWireup attribute of the Page directive is set to true5. The feature in ASP.NET 2.0 that is used to fire a normal postback to a different page in the application is calledAnswer: Cross Page Posting6. In ASP.NET if one wants to set the focus on a particular controlAnswer: Call FOCUS method
7. Which of the following is used to write error message in event Log File?Answer: System.Diagnostics8. If in an ASP.NET application one want to create http handlers which of the interface is usedAnswer: IHttpHandlerFactory9. I have an ASP.NET application. I have a page loaded from server memory. At this instance which of the following methods gets firedAnswer: Load()10. A developer wanted to achieve graphics in his display using ASP.NET. Which of the following web controls are available in ASP.NET to achieve the above?Answer: AdRotator
11. Which of the following denote value that can be taken by Cache-Control of ASP.NET?
Answer: All the Above12. Which of the following denote page code model in ASP.NET?Answer: Both A) and B)13. The control used in ASP.NET to display information from data set but with better formatting and editing behavior isAnswer: DataList14. Which of the following denote New Data-bound Controls used with ASP.NETAnswer: All the Above15. Which of the following is true about session in ASP.NET?Answer: ASP.NET automatically delete sessions after configurable timeout interval16. Setting the following properties for object in ASP.NET results in
Response.Buffer = True Response.ExpiresAbsolute = Now().Subtract(New TimeSpan(1, 0, 0, 0)) Response.Expires = 0 Response.CacheControl = "no-cache"
Answer: Avoid page to be cached
17. In ASP.NET what does the following return< % Response.Write(System.Environment.WorkingSet.ToString())% >Answer: Gives the memory working set18. Forms based authentication is otherwise called in ASP.NET as Cookie Authentication because Forms authentication uses cookies to allow applications to track users throughout their visit.Answer: Cookie Authentication19. If a developer of ASP.NET defines style information in a common location. Then that location is called asAnswer: Theme20. Which of the following denote the web control associated with Table control function of ASP.NET?Answer: TableRow21. If one uses ASP.NET configuration system to restrict access which of the following is TRUE?
Answer: The access is restricted only to ASP.NET files
1. C# (C-Sharp) was developed by
Microsoft
2. What is C# (C-Sharp) ?
An Programming Language
3. C# (C-Sharp) belong to which framework ?
.NET
4. What is CLR ?
Common Language Runtime
5. Object Oriented Programming (OOP) is a style of programming in which your code is broken up into units, known as
objects and classes
6. There are, however, some advanced features of C++, such as __ that are not supported in .NET, and are therefore, not available in managed code.
templates
7. Using C# you can, for example, write a ___ web page
static
8. Using C# you can, for example, write ___ of a distributed application
a component
9. This is because they all have the same familiar Windows ___ at their core.
IDE
10. What is OLE ?
Object Linking and Embedding
11. What actually manages
your code ?
CTS
12. When the . NET runtime loads and runs code, this is the language that it expects to find the code in.
Just-in-Time Compilation
13. When you compile managed code, the ____ actually emits IL.
translator
14. ____ this is a minimum set of standards that guarantees that code can be accessed from any language.
Common Type System
15. Common Language Specification: This is a minimum set of standards that guarantees that code can be accessed from any
application
16. Just-in-Time (JIT) Compilation: This is the term for the process of performing the ___ stage of compilation from IL into native machine code.
intermediate
17. The function call generated by a non-OOP compiler causes what is called ___ binding
strong
18. You create a string reference:
string s;
19. When you create a reference, you want to connect it with a new object. You do so, in general, with the
round brackets
20. There are six different places to store data. This is a general-purpose pool of memory (also in the RAM area) where all C# objects live.
The stack1.Does C# support multiple-inheritance? No. But you can use Interfaces.
2.Where is a protected class-level variable available? It is available to any sub-class derived from base class
3.Are private class-level variables inherited? Yes, but they are not accessible.
4.Describe the accessibility modifier “protected internal”. It is available to classes that are within the same assembly and derived from the specified base class.
6.Which class is at the top of .NET class hierarchy? System.Object.
7.What does the term immutable mean?The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
8.What’s the difference between System.String and System.Text.StringBuilder classes?System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
9.What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
10.Can you store multiple data types in System.Array?No.
11.What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?The Clone() method returns a new array (a shallow copy) object containing all the elements
in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object.
12.How can you sort the elements of the array in descending order?By calling Sort() and then Reverse() methods.
13.What’s the .NET collection class that allows an element to be accessed using a unique key?HashTable.
14.What class is underneath the SortedList class?A sorted HashTable.
15.Will the finally block get executed if an exception has not occurred?Yes.
16.What’s the C# syntax to catch any possible exception?A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
17.Can multiple catch blocks be executed for a single try statement?No. Once the proper catch block processed, control is transferred to the finally block .
18.Explain the three services model commonly know as a three-tier application?Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).
Class Questions
1.What is the syntax to inherit from a class in C#? Place a colon and then the name of the base class.Example: class MyNewClass : MyBaseClass
2.Can you prevent your class from being inherited by another class? Yes. The keyword “sealed” will prevent the class from being inherited.
3.Can you allow a class to be inherited, but prevent the method from being over-ridden?Yes. Just leave the class public and make the method sealed.
4.What’s an abstract class?A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.
5.When do you absolutely have to declare a class as abstract?
1. When the class itself is inherited from an
abstract class, but not all base abstract methods have been overridden.
2. When at least one of the methods in the class is abstract.
6.What is an interface class?Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.
7.Why can’t you specify the accessibility modifier for methods inside the interface?They all must be public, and are therefore public by default.
8.Can you inherit multiple interfaces?Yes. .NET does support multiple interfaces.
9.What happens if you inherit multiple interfaces and they have conflicting method names?It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.
10. What’s the difference between an interface and abstract class?In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.
11. What is the difference between a Struct and a Class?Structs are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that structs cannot inherit.
Method and Property Questions
1. What’s the implicit name of the parameter that gets passed into the set method/property of a class? Value. The data type of the value parameter is defined by whatever data type the property is declared .
2. What does the keyword “virtual” declare for a method or property? The method or property can be overridden.
3. How is method overriding different from method overloading? When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.
4. Can you declare an override method to be static if the original method is not static?
No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)
5. What are the different ways a method can be overloaded? Different parameter data types, different number of parameters, different order of parameters.
6. If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
Events and Delegates
1. What’s a delegate? A delegate object encapsulates a reference to a method.
2. What’s a multicast delegate? A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.
3. What’s the implicit name of the parameter that gets passed into the class’ set method?Value, and it’s datatype depends on whatever variable we’re changing.
4. How do you inherit from a class in C#? Place a colon and then the name of the base class.
5. Does C# support multiple inheritance?No, use interfaces instead.
6. When you inherit a protected class-level variable, who is it available to?Classes in the same namespace.
7. Are private class-level variables inherited?Yes, but they are not accessible, so looking at it you can honestly say that they are not inherited.
8. Describe the accessibility modifier protected internal.?It’s available to derived classes and classes within the same Assembly (and naturally from the base class it’s declared in).
9. C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write? Two. Once you write at least one constructor, C# cancels the freebie constructor, and now you have to write one yourself, even if there’s no implementation in it.
10. What’s the top .NET class that everything is derived from? System.Object.
11. How’s method overriding different from overloading? When overriding, you change the method
behavior for a derived class. Overloading simply involves having a method with the same name within the class.
12. What does the keyword virtual mean in the method definition?The method can be over-ridden.
13. Can you declare the override method static while the original method is non-static?No, you can’t, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override.
14. Can you override private virtual methods?No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
15. Can you prevent your class from being inherited and becoming a base class for some other classes? Yes, that’s what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It’s the same concept as final class in Java.
16. Can you allow class to be inherited, but prevent the method from being over-ridden? Yes, just leave the class public and make the method sealed.
17. What’s an abstract class? A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it’s a blueprint for a class without any implementation.
18. When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
19. What’s an interface class?It’s an abstract class with public abstract methods all of which must be implemented in the inherited classes.
20. Why can’t you specify the accessibility modifier for methods inside the interface? They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it’s public by default.
21. Can you inherit multiple interfaces? Yes, why not.
22. And if they have conflicting method names? It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as
compiler cares you’re okay.
23. What’s the difference between an interface and abstract class?In the interface all methods must be abstract, in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes.
24. How can you overload a method? Different parameter data types, different number of parameters, different order of parameters.
25. If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor? Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
26. What’s the difference between System.String and System.StringBuilder classes?System.String is immutable, System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
27. Is it namespace class or class namespace? The .NET class library is organized into namespaces. Each namespace contains a functionally related group of classes so natural namespace comes first.
2. Who is a protected class-level variable available to? It is available to any sub-class (a class inheriting this class).3. Are private class-level variables inherited? Yes, but they are not accessible. Although they are not visible or accessible via the class interface, they are inherited. 4. Describe the accessibility modifier “protected internal”. It is available to classes that are within the same assembly and derived from the specified base class. 5. What’s the top .NET class that everything is derived from? System.Object. 6. What does the term immutable mean?The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory. 7. What’s the difference between System.String and System.Text.StringBuilder
classes?System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed. 8. What’s the advantage of using System.Text.StringBuilder over System.String?StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.9. Can you store multiple data types in System.Array?No. 10. What’s the difference between the System.Array.CopyTo() and System.Array.Clone() ?The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object. 11. How can you sort the elements of the array in descending order?By calling Sort() and then Reverse() methods. 12. What’s the .NET collection class that allows an element to be accessed using a unique key?HashTable. 13. What class is underneath the SortedList class?A sorted HashTable. 14. Will the finally block get executed if an exception has not occurred?Yes.15. What’s the C# syntax to catch any possible exception?A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write
catch {}. 16. Can multiple catch blocks be executed for a single try statement?No. Once the proper catch block processed, control is transferred to the finally block (if there are any). 17. Explain the three services model commonly know as a three-tier application.Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).
C# Interview Questions | C Sharp Interview Questions
1) Explain about C#?C # is also known as c sharp. It is a programming language introduced by Microsoft. C# contains features similar to Java and C++. It is specially designed to work with Microsoft .NET platform.
2) Explain about the rules for naming classes in C#?These are the rules for naming classes in c sharp.• Must begin with a letter. This letter may be followed by a sequence of letters, digits (0-9), or ‘_’. The first character in a class name cannot be a digit.• Must not contain any embedded space or symbol like ? - + ! @ # % & * ( ) { } [ ] , : ; ‘ “ \ and/. However an underscore _ can be used wherever a space is required.• Must not use a keyword for a class name.
3) What are the rules to be followed while naming variables in C#.The following rules are used for naming variables in C#.* Must begin with a letter or an underscore _ which may be followed by a sequence of letters, digits (0-9), or ‘_’. The first character in a variable name cannot be a digit.* Must not contain any embedded space or symbol like ? - + ! @ # % & * ( ) { } [ ] , : ; ‘ “ \ and/. However an underscore _ can be used wherever a space is required.• Must be unique
• Can have any number of characters• Keywords cannot be used as variable names.
4) What are the different types of Data?There are two different types of data supported by C#. They are1) Value types: -They directly contain data. When you declare an int variable, the system allocates memory to store the value.2) Reference type: -The reference types do not maintain data but they contain a reference to the variables, which are stored in memory. This means that if the value in the memory location is modified by one of the variables, the other variables automatically reflect the changes value
5) Explain about member functions?A function is a set of statements that perform a specific task in response to a message. The functions of a class are called member functions in Csharp. Member functions are declared inside the class. The function declaration introduces the function in the class and the function definition contains the function code.
6) Explain about comment entry?Comments are a part of the program and are used to explain the code. Compilers ignore comment entries. If a comment entry spans more than one line, it has to be enclosed within ‘/*’ and ‘*/’. The symbol ‘//’ treats the rest of code within the same line as a comment.
7) What are operators?Applications use operators to process the data entered by a user. Operators like + and – are used to process variables and return a value. An operator is a set of one or more characters that is used for computations or comparisons. Operators can transform one or more data values, called operands into a new data value.
8) Explain about the break statement?A break statement is used to exit the switch statement. This prevents the execution of the remaining case structures by ending the execution of the switch case construct. Each
break statement terminates the enclosing switch statement and the flow of control. If none of the cases match the default case is invoked.
9) Define encapsulation?Encapsulation literally means to enclose in or as if in a capsule. Encapsulation is defined as the process of enclosing one or more items within a physical or logical package. It involves preventing access to nonessential details.
10) Define access specifier with reference to class?An access specifier defines the scope of a class member. A class member refers to the variables and functions in a class. A program can have one or more classes. You may want some members of a class to be accessible to other classes. But, you may not want some other members of the class to be accessible outside the class.
11) Describe about private access specifier?
The private access specifier allows a class to hide its member variables and member functions from other class objects and functions. Therefore, the private member of a class is not visible outside a class. If a member is declared private, only the functions of that class can access the member. Even the instance of the class cannot access its members
12) Explain about protected internal access specifier?This specifier allows a class to hide its member variables and member functions to be accessed from other class objects and functions, except the child class, within the application. The protected internal access specifier becomes important while implementing inheritance.
13) Define parameter by value?Pass by value is the default mechanism for passing parameters to a method. The simplest definition of a value parameter is a data type name followed by a variable name. When a
method is called, a new storage location is created for each value parameter. The values of the corresponding expressions are copied into them. The expression supplied for each value parameter must be similar to the declaration of the value parameter.
14) State the methods through which parameters can be passed?Parameters can be passed by using any one of the following mechanism.Value: -They are sometimes called in or out parameters; therefore, the data can be transferred into the method but cannot be transferred out.Reference: -Are sometimes called in or out parameters, therefore, the data can be transferred into the method and out again.Output: -Are sometimes called out parameters, data can be transferred out of the method.
15) Explain about reference parameter?A reference parameter is a reference to a memory location of a data member. Unlike a value parameter, a reference parameter does not create a new storage location. Instead a reference parameter represents the same location in memory as the variable that is supplied in the method call.
16) How do you use a structure?A structure is a value type data type. When you want a single variable to hold related data of various data types, you can create a structure. To create a structure you use the struct keyword.
17) What is an enumerator?Enumeration is a value data type, which means that enumeration contains its own values and cannot inherit or pass inheritance. Enumerator allows you to assign symbolic names or integral constants.