C#

C # Programming

This Article is about a programming language. For other uses, see C –Sharp disambiguation. The correct title of this article is C# programming language. The substitution or omission of the # is because of technical restrictions.

C# pronounced see sharp is a multi paradigm programming language encompassing strong typing, imperative, declarative, functional, procedural, generic, object- oriented class based, and component oriented programming disciplines. It was developed by Microsoft within its DOT NET initiative and later approved as a standard by Ecma. C# is built on the syntax and semantics of C++, allowing c programmers to take advantage of DOT NET and the common language run time. 

C# is intended to be a simple, modern, general purpose, object oriented programming language. Its development team is lead by Anders Hejlsberg. 

This section provides detailed information on key C# language features and features accessible to C# through the .NET Framework. 

Most of this section assumes that you already know something about C# and general programming concepts. If you are a complete beginner with programming or with C#, you might want to visit the, where you can find many tutorials, samples and videos to help you get started.

For information about specific keywords, operators and coprocessor directives, see. For information about the C# Language Specification, see C# language specification.

Although C# is derived from the, it introduces some unique and powerful features, such as delegates which can be viewed as type-safe function pointers and lambda expressions which introduce elements of functional programming languages, as well as a simpler single class inheritance model than C++ and, for those of you with experience in C-like languages, a very familiar syntax that may help beginners become proficient faster than its predecessors. Similar to, comes with an extensive class library, and supports exception handling, multiple types of, and separation of interfaces from implementations. Those features, combined with its powerful development tools, multi-platform support, and generics, make C# a good choice for many types of software development projects, projects, projects implemented by individuals or large or small teams, Internet applications, and projects with strict reliability requirements. Testing frameworks such as and thus a good language for use with XP. Its helps to prevent many programming errors that are common in weakly typed languages.

C # pronounced See Sharp is a multipurpose computer suitable for a wide variety of development needs. This Wiki book introduces C# language fundamentals and covers a variety of the base class libraries provided by the Microsoft .NET Framework.

C# is a modern and innovative programming language that carefully incorporates features found in the most common industry and research languages. In keeping with the design philosophy of C#, Microsoft has introduced several potential new features to the C# language that increase developer productivity with language constructs.

Explains C#

The term’s # character derives its name from the musical sharp key, which denotes a one semitone pitch increase. C# is pronounced see sharp. 

C# improved and updated many C and C++ features, including the following,

C# has a strict Boolean data variable type, such as bool, whereas C++ bool variable types may be returned as integers or pointers to avoid common programming errors.

C# automatically manages inaccessible object memory using a garbage collector, which eliminates developer concerns and memory leaks.

C# type is safer than C++ and has safe default conversions only, which are implemented during compile or runtime.

No implicit conversions between Booleans, enumeration members and integers may be converted to an enumerated type. User-defined conversions must be specified as explicit or implicit, versus the C++ default implicit conversion operators and copy constructors.

C # Means

C# is a general object-oriented programming language for networking and Web development. C# is specified as a common language infrastructure language.

             Dutch software engineer Anders Hejlsberg formed a team to develop C# as a complement to Microsoft’s NET framework. Initially, C# was developed as C-Like Object Oriented Language. The actual name was changed to avert potential trademark issues.

C # Definition

          C sharp an object-oriented programming language that is based on C++ with elements from Visual Basic and Java. Like Java, C# provides automatic garbage collection, whereas traditional C and C++ do not. C# was created by Microsoft and also standardized by the European Computer Manufacturers Association. Microsoft designed C# as its flagship programming language for the .NET environment.

C# pronounced C-sharp is an language from Microsoft that aims to combine the computing power of with the programming ease of. C# is based on C++ and contains features similar to those of C# is designed to work with Microsoft's platform. Microsoft's aim is to facilitate the exchange of information and services over the Web, and to enable developers to build highly applications. C# simplifies programming through its use of Extensible Markup Language and Simple Object Access Protocol which allow access to a programming or  without requiring the programmer to write additional code for each step. Because programmers can build on existing code, rather than repeatedly duplicating it, C# is expected to make it faster and less expensive to get new products and services to market.

Microsoft is collaborating with ECMA, the international standards body, to create a standard for C#. International Standards Organization recognition for C# would encourage other companies to develop their own versions of the language. Companies that are already using C# include Apex Software, Bunka Orient, Component Source, devSoft, FarPoint Technologies, LEAD Technologies, Prototype, and Seagate Software.

Categories of data types

CTS separate data types into two categories,

1.       Reference types
2.       Value types

Instances of value types do not have referential identity or referential comparison semantics - equality and inequality comparisons for value types compare the actual data values within the instances, unless the corresponding operators are overloaded. Value types are derived from System.Value Type, always have a default value, and can always be created and copied. Some other limitations on value types are that they cannot derive from each other but can implement interfaces and cannot have an explicit default parameter less constructor. Examples of value types are all primitive types, such as int a signed 32-bit integer, float a 32-bit  floating-point number, char a 16-bit Unicode code unit, and System. Date Time identifies a specific point in time with nanosecond precision. Other examples are enum and struct user defined structures.

In contrast, reference types have the notion of referential identity - each instance of a reference type is inherently distinct from every other instance, even if the data within both instances is the same. This is reflected in default equality and inequality comparisons for reference types, which test for referential rather than structural equality, unless the corresponding operators are overloaded such as the case for System. String. In general, it is not always possible to create an instance of a reference type, nor to copy an existing instance, or perform a value comparison on two existing instances, though specific reference types can provide such services by exposing a public constructor or implementing a corresponding interface such as ICloneable or IComparable. Examples of reference types are object the ultimate base class for all other C# classes, System.String a string of Unicode characters, and System.Array a base class for all C# arrays.

Preprocessor

C# features preprocessed directives that allow programmers to define, but not macros. Conditionals such as #if, #endif, and #else are also provided. Directives such as #region give hints to editors for code folding.

public class Foo

{

    #region Constructors

    public Foo() {}

    public Foo(int firstParam) {}

    #endregion

    #region Procedures

    public void IntBar(int firstParam) {}

    public void StrBar(string firstParam) {}

    public void BoolBar(bool firstParam) {}

    #endregion

}

Implementations

The reference C# compiler is which closed-source is.

Other C# compilers exist, often including an implementation of the and the DOT NET class libraries up to .NET 2.0,

The project provides a C# compiler, a complete open source implementation of the Common Language Infrastructure including the required framework libraries as they appear in the ECMA specification and a nearly complete implementation of the Microsoft proprietary DOT NET class libraries up to DOT NET 3.5. As of Mono 2.6, no plans exist to implement, is planned for a later release; and there are only partial implementations,

The project also provides an open source C# compiler, a nearly complete implementation of the Common Language Infrastructure including the required framework libraries as they appear in the ECMA specification, and subset of some of the remaining Microsoft proprietary DOT NET class libraries up to DOT NET 2.0 those not documented or included in the ECMA specification, but included in Microsoft's standard DOT NET Framework distribution.

Microsoft's Rotor project currently called licensed for educational and research use only provides a implementation of the CLR runtime and a C# compiler, and a subset of the required framework libraries in the ECMA specification up to C# 2.0, and supported on Windows XP only.

What is C#

C# pronounced see sharp or C Sharp is one of many .NET programming languages. It is object-oriented and allows you to build reusable components for a wide variety of application types Microsoft introduced

C# is an evolution of the C and C++ family of languages. However, it borrows features from other programming languages, such as Delphi and Java. If you look at the most basic syntax of both C# and Java, the code looks very similar, but then again, the code looks a lot like C++ too, which is intentional. Developers often ask questions about why C# supports certain features or works in a certain way. The answer is often rooted in its C++ heritage.

Pounced See Sharp a hybrid of C and C++, it is a Microsoft programming language developed to compete with Sun’s java language. C # is an object oriented programming language used with XML based Web service on the DOT NET platform and designed for improving productivity in the development of Web application. C# boasts type- safety, garbage collection, simplified type declarations, versioning and scalability support, and other features that make developing solutions faster and easier, especially for COM+ and web services. Microsoft critics have pointed to the similarities between C# and Java.

Microsoft C#

A number of developers have begun building software using the C# programming language. Even within Microsoft, C# has been used to build several shipping applications, including the .NET Framework, MSN Web properties, and the Tablet PC SDK. As such, C# has proven itself as a language suitable for the construction of high-quality commercial software.

Many of the features in the C# language were created with four different design goals in mind,

A unified type system and simplifying the way that value and reference types are used by the language.

A component-based design established through features such as XML comments, attributes, properties, events and delegates.

Practical developer headroom established through the unique capabilities of the C# language, including safe pointer manipulation, overflow checking, and more.

Pragmatic language constructs, such as the foreach and using statements, which improve developer productivity.

In the Visual Studio for Yukon version of the C# language, Microsoft plans to build on an already elegant and expressive syntax by incorporating a variety of features across a broad spectrum of research and industry languages. Included among these language features are generics, iterates, anonymous methods and partial types.

C # Explanations

C# is one of the most used programming languages today. It is based on the concepts of C++, and is very similar to Java. If you know either of these languages, you should be able to quite easily. You can then develop C# applications and run them on the currently popular DOT NET framework.

Classes, Members and Objects

The most basic building block of a C# code are classes and objects. Every class has members that define the data and behavior of the class. Objects are real instances of a class. You can give public or private access to the classes defined in your program. Private classes can have only one object instance, which helps to hide data from the rest of the code. You need to start and end a class definition with left and right curly brackets respectively, this forms the class body.

Methods

You will find the mention of methods in any, Besides classes, you have methods, and each name is followed by a pair of open and close brackets. These carry out specific functions and enable you to break down the code in a modular fashion for the sake of simplicity. Every C# code starts off with the Main method. This is a static method, and can thus be accessed only by classes, and not by objects.

Variables

All data is stored using variables, each having a name and type. The data that you can assign to a variable is limited by its data type. For example, integer value cannot be assigned to a string variable. The value of a variable may change during the execution of the program. If there is no value assigned, the default value is taken for that data type.

Constants

The other elements that holds data in a C# program are constants; these have fixed values that are set during initialisation. These are preceded by the keyword const. For example,

const int X = 5;

It is a good practice to write the names of constants in upper case for the sake of readability, although the compiler would process it the same even if it were written in lower case.

Arrays

Like C and C++, C# also includes arrays. The difference here is that the square brackets that indicate the position of the array elements follow the type and not the array name or identifier. For example,

int[] samplearray;

Note that this declaration is not enough to create an actual instance of the array. You can do this as follows,

int[] samplearray = new int[3];

If you want to assign values to this array, include them within curly braces right after int[3] in the above statement.

Array indexing begins at zero. The size of an array is not fixed at the time it is defined; the number of elements within it can be changed anytime during the code. Square brackets following the array name allow you to access individual elements.

C# Application Run

An important point is that C# is a managed language, meaning that it requires the to execute. Essentially, as an application that is written in C# executes, the CLR is managing memory, performing garbage collection, handling exceptions, and providing many more services that you, as a developer, don't have to write code for. The C# compiler produces Intermediate Language, rather than machine language, and the CLR understands IL. When the CLR sees the IL, it Just-In-Time compiles it, method by method, into compiled machine code in memory and executes it. As mentioned previously, the CLR manages the code as it executes.

Because C# requires the CLR, you must have the CLR installed on your system. All new Windows operating systems ship with a version of the CLR and it is available via Windows Update for older systems. The CLR is part of the DOT NET, so if you see updates for the DOT NET Framework Runtime, it contains the CLR and DOT NET Framework Class Library. It follows that if you copy your C# application to another machine, then that machine must have the CLR installed too.

C # in Advanced Topics

Inheritance: Re-using existing code to improve or specialize the functionality of an object.

Interfaces: Define a template, on which to base sub-classes.

Delegated and Events: Learn about delegates, anonymous delegates, lambda expressions, and events.

Abstract Classes: Build partially implemented classes.

Partial classes: Split a class over several files to allow multiple users to develop, but also to stop code generators interfering with source code.

Generics: Allow commonly used collections and classes to appear to have specialization for your custom class.

Extension Methods: Extend the functionality of existing types.

Object Life Time: Learn about the lifetime of objects, where they are allocated and learn about garbage collection.

Design Patterns: Learn commonly used design methodologies to simplify and/or improve your development framework.

C # Basic

Basic Syntax: Describes the basics in how the applications you write will be interpreted.

Naming Conventions: Quickly describes the generally accepted naming conventions for C#.

Variables: The entities used to store data of various shapes.

Operators: Summarizes the operators, such as the '+' in addition, available in C#.

Data structures: Enumerations, struct, and more.

Control Statement: Loops, conditions, and more. How the program flow is controlled.

Exceptions: Responding to errors that can occur.

Libraries

The C# specification details a minimum set of types and class libraries that the compiler expects to have available. In practice, C# is most often used with some implementation of the CLI, which is standardized as Common Language Infrastructure.

C # Data Types

             

             There are Types in C #

1.     Value Types

2.     Reference Types

3.     Object Types

4.     Dynamic Types

5.     String Types

6.     Pointer Types

Value Types

Value type variables can be assigned a value directly. They are derived from the class System.Value Type. 

The value types directly contain data. Some examples are int, char, float, which stores numbers, alphabets, and floating point numbers, respectively. When you declare an int type, the system allocates memory to store the value.

Reference Types

The reference types do not contain the actual data stored in a variable, but they contain a reference to the variables.

In other words, they refer to a memory location. Using more than one variable, the reference types can refer to a memory location. If the data in the memory location is changed by one of the variables, the other variable automatically reflects this change in value. Example of built-in reference types are, object, dynamic and string.

Object Types

The Object Type is the ultimate base class for all data types in C# Common Type System. Object is an alias for System. Object class. So object types can be assigned values of any other types, value types, and reference types, predefined or user-defined types. However, before assigning values, it needs type conversion. 

When a value type is converted to object type, it is called boxing and on the other hand, when an object type is converted to a value type, it is called unboxing.

Object obj;

Obj = 100; 

Dynamic Types

You can store any type of value in the dynamic data type variable. Type checking for these types of variables takes place at run-time.

Syntax for declaring a dynamic type is:

               dynamic = value;

Dynamic types are similar to object types except that type checking for object type variables takes place at compile time, whereas that for the dynamic type variables take place at run time.

String Type

The String Type allows you to assign any string values to a variable. The string type is an alias for the System.String class. It is derived from object type. The value for a string type can be assigned using string literals in two form,

                              String str = Tutorials Point;

Pointer Types

Pointer type variables store the memory address of another type. Pointers in C# have the same capabilities as in C or C++.

Syntax for declaring a pointer type is:

type* identifier;

C # Operator Over Loading

You can redefine or overload most of the built-in operators available in C#. Thus a programmer can use operators with user-defined types as well. Overloaded operators are functions with special names the keyword operator followed by the symbol for the operator being defined. Like any other function, an overloaded operator has a return type and a parameter list. For Example

public static Box operator+ (Box b, Box c)

{

   Box box = new Box();

   box.length = b.length + c.length;

   box.breadth = b.breadth + c.breadth;

   box.height = b.height + c.height;

   return box;

}

Overloadable and Non-Overloadable Operators

The following table describes the overload ability of the operators in C#,

Operators	Description
+, -, !, ~, ++, --	These unary operators take one operand and can be overloaded.
+, -, *, /, %	These binary operators take one operand and can be overloaded.
==, !=, <, >, <=, >=	The comparison operators can be overloaded
&&, ||	The conditional logical operators cannot be overloaded directly.
+=, -=, *=, /=, %=	The assignment operators cannot be overloaded.
=, ., ?:, ->, new, is, sizeof, typeof	These operators cannot be overloaded.

C# - Multithreading

A thread is defined as the execution path of a program. Each thread defines a unique flow of control. If your application involves complicated and time consuming operations then it is often helpful to set different execution paths or threads, with each thread performing a particular job.

Threads are lightweight processes. One common example of use of thread is implementation of concurrent programming by modern operating systems. Use of threads saves wastage of CPU cycle and increase efficiency of an application.

So far we have written programs where a single thread runs as a single process which is the running instance of the application. However, this way the application can perform one job at a time. To make it execute more than one task at a time, it could be divided into smaller threads.

Thread Life Cycle

The life cycle of a thread starts when an object of the System.Threading.Thread class is created and ends when the thread is terminated or completes execution.

Following are the various states in the life cycle of a thread,

The Unstarted State: It is the situation when the instance of the thread is created but the Start method has not been called.

The Ready State: It is the situation when the thread is ready to run and waiting CPU cycle.

The Not Runnable State: a thread is not runnable, when:

•          Sleep method has been called
•          Wait method has been called
•          Blocked by I/O operations

The Dead State: It is the situation when the thread has completed execution or has been aborted.

The Main Thread

In C#, the System.Threading.Thread class is used for working with threads. It allows creating and accessing individual threads in a multithreaded application. The first thread to be executed in a process is called the main thread. 

When a C# program starts execution, the main thread is automatically created. The threads created using the Thread class are called the child threads of the main thread. You can access a thread using the CurrentThread property of the Thread class. 

using System;

using System. Threading;

namespace Multithreading Application

{

    class MainThreadProgram

    {

        static void Main(string[] args)

        {

            Thread th = Thread.CurrentThread;

            th.Name = "MainThread";

            Console.WriteLine("This is {0}", th.Name);

            Console.ReadKey();

        }

    }

}

Creating Threads

Threads are created by extending the Thread class. The extended Thread class then calls the Start() method to begin the child thread execution. 

The following program demonstrates the concept,

using System;

using System.Threading;

namespace MultithreadingApplication

{

    class ThreadCreationProgram

    {

        public static void CallToChildThread()

        {

            Console.WriteLine("Child thread starts");

        }

       

        static void Main(string[] args)

        {

            ThreadStart childref = new ThreadStart(CallToChildThread);

            Console.WriteLine("In Main: Creating the Child thread");

            Thread childThread = new Thread(childref);

            childThread.Start();

            Console.ReadKey();

        }

    }

}

When the above code is compiled and executed, it produces the following result,

In Main: Creating the Child thread

Child thread starts

Managing Threads

The Thread class provides various methods for managing threads.

The following example demonstrates the use of the sleep() method for making a thread pause for a specific period of time.

using System;

using System.Threading;

namespace MultithreadingApplication

{

    class ThreadCreationProgram

    {

        public static void CallToChildThread()

        {

            Console.WriteLine("Child thread starts");

            int sleepfor = 5000;

            Console.WriteLine("Child Thread Paused for {0} seconds",

                              sleepfor / 1000);

            Thread.Sleep(sleepfor);

            Console.WriteLine("Child thread resumes");

        }

       

        static void Main(string[] args)

        {

            ThreadStart childref = new ThreadStart(CallToChildThread);

            Console.WriteLine("In Main: Creating the Child thread");

            Thread childThread = new Thread(childref);

            childThread.Start();

            Console.ReadKey();

        }

    }

}

When the above code is compiled and executed, it produces the following result,

In Main: Creating the Child thread

Child thread starts

Child Thread Paused for 5 seconds

Child thread resumes

Destroying Threads

The Abort() method is used for destroying threads.

The runtime aborts the thread by throwing a ThreadAbortException. This exception cannot be caught, the control is sent to the finally block, if any. 

Why Use C#

C# is an elegant, simple, type-safe, object-oriented language that allows enterprise programmers to build a breadth of applications.

C# also gives you the capability to build durable system-level components by virtue of the following features,

Full COM/Platform support for existing code integration.

Robustness through garbage collection and type safety.

Security provided through intrinsic code trust mechanisms.

Full support of extensible metadata concepts.

You can also interoperate with other languages, across platforms, with legacy data, by virtue of the following features,

Full interoperability support through COM+ 1.0 and .NET Framework services with tight library-based access. XML support for Web-based component interaction. Versioning to provide ease of administration and deployment.

C # Language and the DOT NET Framework

C# is an elegant and type-safe object-oriented language that enables developers to build a variety of secure and robust applications that run on the .NET Framework. You can use C# to create Windows client applications, XML Web services, distributed components, client-server applications, database applications, and much, much more. Visual C# provides an advanced code editor, convenient user interface designers, integrated debugger, and many other tools to make it easier to develop applications based on the C# language and the DOT NET Framework.

C # Language

C# syntax is highly expressive, yet it is also simple and easy to learn. The curly-brace syntax of C# will be instantly recognizable to anyone familiar with C, C++ or Java. Developers who know any of these languages are typically able to begin to work productively in C# within a very short time. C# syntax simplifies many of the complexities of C++ and provides powerful features such as null able value types, enumerations, delegates, lambda expressions and direct memory access, which are not found in Java. C# supports generic methods and types, which provide increased type safety and performance, and iterates, which enable implementers of collection classes to define custom iteration behaviours that are simple to use by client code. Language-Integrated Query expressions make the strongly-typed query a first-class language construct.

As an object-oriented language, C# supports the concepts of encapsulation, inheritance, and polymorphism. All variables and methods, including the Main method, the application's entry point, are encapsulated within class definitions. A class may inherit directly from one parent class, but it may implement any number of interfaces. Methods that override virtual methods in a parent class require the override keyword as a way to avoid accidental redefinition. In C#, a struct is like a lightweight class, it is a stack-allocated type that can implement interfaces but does not support inheritance.