C# (C Sharp) Question:-
1.What is C#?
- C# (pronounced "C sharp") is a simple, modern, object-oriented, and type-safe programming language.
- It will immediately be familiar to C and C++ programmers.
C# combines the high productivity of
Rapid Application Development (RAD) languages.
2. What are the types of
comment in C#?
There are 3 types of comments in C#.
- Single line (//)
- Multi (/* */)
- Page/XML Comments (///).
3.What are the
namespaces used in C#.NET?
Namespace is a logical grouping of class.
- using System;
- using System.Collections.Generic;
- using System.Windows.Forms;
4.What are the
characteristics of C#?
There are several characteristics of C# are :
- Simple
- Type safe
- Flexible
- Object oriented
- Compatible
- Consistent
- Interoperable
- Modern
5.How does C# differ
from C++?
- C# does not support #include statement. It uses only using statement.
- In C# , class definition does not use a semicolon at the end.
- C# does not support multiple code inheritance.
- Casting in C# is much safer than in c++.
- In C# switch can also be used on string values.
- Command line parameters array behave differently in C# as compared to C++.
6.What are the basic
concepts of object oriented programming?
It is necessary to understand some of the concepts used
extensively in object oriented programming.These include
- Objects
- Classes
- Data abstraction and encapsulation
- Inheritance
- Polymorphism
- Dynamic Binding
- Message passing.
7.Can you inherit
multiple interfaces?
Yes. Multiple interfaces may be
inherited in C#.
8.What is inheritance?
Inheritance is deriving the new
class from the already existing one.
9.Define scope?
Scope refers to the region of code
in which a variable may be accessed
10.What is the difference
between public, static and void?
- public :The keyword public is an access modifier that tells the C# compiler that the Main method is accessible by anyone.
- static :The keyword static declares that the Main method is a global one and can be called without creating an instance of the class. The compiler stores the address of the method as the entry point and uses this information to begin execution before any objects are created.
- void : The keyword void is a type modifier that states that the Main method does not return any value.
11.What are the modifiers
in C#?
- Abstract
- Sealed
- Virtual
- Const
- Event
- Extern
- Override
- Readonly
- Static
- New
12.What are the
types of access modifiers in C#?
Access modifiers in C# are :
- public
- protect
- private
- internal
- internal protect
13.What is boxing
and unboxing?
Implicit conversion of value type to
reference type of a variable is known as BOXING, for example integer to object
type conversion.
Conversion of reference type variable back to value type is called as UnBoxing.
Conversion of reference type variable back to value type is called as UnBoxing.
14What is object?
An object is an instance of a class.
An object is created by using operator new. A class that creates an object in
memory will contain the information about the values and behaviours (or
methods) of that specific object.
15.Where are the types of
arrays in C#?
- Single-Dimensional
- Multidimensional
- Jagged arrays.
16.What is the
difference between Object and Instance?
An instance of a user-defined type
is called an object. We can instantiate many objects from one class.
An object is an instance of a class.
An object is an instance of a class.
17.Define destuctors?
A destructor is called for a
class object when that object passes out of scope or is explicitly deleted.A
destructors as the name implies is used to destroy the objects that have been
created by a constructors.Like a constructor , the destructor is a member
function whose name is the same as the class name but is precided by a
tilde.
18.What is the use of
enumerated data type?
An enumerated data type is another
user defined type which provides a way for attaching names to numbers thereby
increasing comprehensibility of the code. The enum keyword automatically
enumerates a list of words by assigning them values 0,1,2, and so on.
19.Define Constructors?
A constructor is a member function
with the same name as its class. The constructor is invoked whenever an object
of its associated class is created.It is called constructor because it
constructs the values of data members of the class.
20.What is encapsulation?
The wrapping up of data and
functions into a single unit (called class) is known as encapsulation.
Encapsulation containing and hiding information about an object, such as
internal data structures and code.
21.Does c# support
multiple inheritance?
No,its impossible which accepts
multi level inheritance.
22.What is ENUM?
Enum are used to define constants
23.What is a data set?
A DataSet is an in memory
representation of data loaded from any data source
24.What is the difference
between private and public keyword?
- Private : The private keyword is the default access level and most restrictive among all other access levels. It gives least permission to a type or type member. A private member is accessible only within the body of the class in which it is declared.
- Public : The public keyword is most liberal among all access levels, with no restrictions to access what so ever. A public member is accessible not only from within, but also from outside, and gives free access to any member declared within the body or outside the body.
25.Define polymorphism?
Polymorphism means one name,
multiple forms. It allows us to have more than one function with the same name
in a program.It allows us to have overloading of operators so that an operation
can exhibit different behaviours in different instances.
26.What is Jagged Arrays?
- A jagged array is an array whose elements are arrays.
- The elements of a jagged array can be of different dimensions and sizes.
- A jagged array is sometimes called an array–of–arrays.
27.what is an abstract
base class?
An abstract class is a class that is
designed to be specifically used as a base class. An abstract class contains at
least one pure virtual function.
28.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.
29.What is the difference
between ref & out parameters?
An argument passed to a ref
parameter must first be initialized. Compare this to an out parameter, whose
argument does not have to be explicitly initialized before being passed to an
out parameter.
30.What is the use of
using statement in C#?
The using statement is used to
obtain a resource, execute a statement, and then dispose of that resource.
31.What is serialization?
Serialization is the process of
converting an object into a stream of bytes.
De-serialization is the opposite process of creating an object from a stream of bytes.
Serialization / De-serialization is mostly used to transport objects.
De-serialization is the opposite process of creating an object from a stream of bytes.
Serialization / De-serialization is mostly used to transport objects.
32.What are the difference
between Structure and Class?
- Structures are value type and Classes are reference type
- Structures can not have contractors or destructors.
- Classes can have both contractors and destructors.
- Structures do not support Inheritance, while Classes support Inheritance.
33.What is
difference between Class And Interface?
Class : is logical representation of object. It is collection of
data and related sub procedures with defination.
Interface : is also a class containg methods which is not having any definations.Class does not support multiple inheritance. But interface can support.
Interface : is also a class containg methods which is not having any definations.Class does not support multiple inheritance. But interface can support.
34.What is Delegates?
Delegates are a type-safe,
object-oriented implementation of function pointers and are used in many
situations where a component needs to call back to the component that is using
it.
35.What is Authentication
and Authorization?
Authentication is the process of identifying users. Authentication is
identifying/validating the user against the credentials (username and
password).
Authorization performs after authentication. Authorization is the process of granting access to those users based on identity. Authorization allowing access of specific resource to user
Authorization performs after authentication. Authorization is the process of granting access to those users based on identity. Authorization allowing access of specific resource to user
36.What is a base class?
A class declaration may specify a
base class by following the class name with a colon and the name of the base
class. omitting a base class specification is the same as deriving from type
object.
37.Can “this” be used
within a static method?
No ‘This’ cannot be used in a static
method. As only static variables/methods can be used in a static method.
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