Simple way of C# :part 1
1.Introduction :
C# is a modern, general-purpose, object-oriented programming language developed by Microsoft and approved by European Computer Manufacturers Association (ECMA) and International Standards Organization (ISO).
C# was developed by Anders Hejlsberg and his team during the development of .Net Framework.
C# is designed for Common Language Infrastructure (CLI), which consists of the executable code and runtime environment that allows use of various high-level languages on different computer platforms and architectures.
The following reasons make C# a widely used professional language:
It is a modern, general-purpose programming language
It is object oriented.
It is component oriented.
It is easy to learn.
It is a tructured language.
It produces efficient programs.
It can be compiled on a variety of computer platforms.
It is a part of .Net Framework.
Strong Programming Features of C#
Although C# constructs closely follow traditional high-level languages, C and C++ and being an object-oriented programming language. It has strong resemblance with Java, it has numerous strong programming features that make it endearing to a number of programmers worldwide.
Following is the list of few important features of C#:
Boolean Conditions
Automatic Garbage Collection
Standard Library
Assembly Versioning
Properties and Events
Delegates and Events Management
Easy-to-use Generics
Indexers
Conditional Compilation
Simple Multithreading
LINQ and Lambda Expressions
Integration with Windows
2. ENVIRONMENT:
The .Net framework is a revolutionary platform that helps you to write the following types of applications:
Windows applications
Web applications
Web services
The .Net framework applications are multi-platform applications. The framework has been designed in such a way that it can be used from any of the following languages: C#, C++, Visual Basic, Jscript, COBOL, etc. All these languages can access the framework as well as communicate with each other.
The .Net framework consists of an enormous library of codes used by the client languages such as C#. Following are some of the components of the .Net framework:
Common Language Runtime (CLR)
The .Net Framework Class Library
Common Language Specification
Common Type System
Metadata and Assemblies
Windows Forms
ASP.Net and ASP.Net AJAX
ADO.Net
Windows Workflow Foundation (WF)
Windows Presentation Foundation
Windows Communication Foundation (WCF)
LINQ
Integrated Development Environment (IDE) for C#
Microsoft provides the following development tools for C# programming:
Visual Studio 2010 (VS)
Visual C# 2010 Express (VCE)
Visual Web Developer
The last two are freely available from Microsoft official website. Using these tools, you can write all kinds of C# programs from simple command-line applications to more complex applications. You can also write C# source code files using a basic text editor like Notepad, and compile the code into assemblies using the command-line compiler, which is again a part of the .NET Framework.
Visual C# Express and Visual Web Developer Express edition are trimmed down versions of Visual Studio and has the same appearance. They retain most features of Visual Studio. In this tutorial, we have used Visual C# 2010 Express.
You can download it from Microsoft Visual Studio. It gets installed automatically on your machine.
Note: You need an active internet connection for installing the express edition.
3. PROGRAM STRUCTURE:
Before we study basic building blocks of the C# programming language, let us look at a bare minimum C# program structure so that we can take it as a reference in upcoming chapters.
Creating Hello World Program
A C# program consists of the following parts:
Namespace declaration
A class
Class methods
Class attributes
A Main method
Statements and Expressions
Comments
Let us look at a simple code that prints the words "Hello World":
using System;
namespace HelloWorldApplication
{
class HelloWorld
{
static void Main(string[] args)
{
/* my first program in C# */
Console.WriteLine("Hello World");
Console.ReadKey();
}
}
}
===========================================================
Out put : Hello World
Let us look at the various parts of the given program:
The first line of the program using System; - the using keyword is used to include the System namespace in the program. A program generally has multiple using statements.
The next line has the namespace declaration. A namespace is a collection of classes. The HelloWorldApplication namespace contains the class HelloWorld.
The next line has a class declaration, the class HelloWorld contains the data and method definitions that your program uses. Classes generally contain multiple methods. Methods define the behavior of the class. However, the HelloWorld class has only one method Main.
The next line defines the Main method, which is the entry point for all C# programs. The Main method states what the class does when executed.
The next line /*...*/ is ignored by the compiler and it is put to add comments in the program.
The Main method specifies its behavior with the statement Console.WriteLine("Hello World");
WriteLine is a method of the Console class defined in the System namespace. This statement causes the message "Hello, World!" to be displayed on the screen.
The last line Console.ReadKey(); is for the VS.NET Users. This makes the program wait for a key press and it prevents the screen from running and closing quickly when the program is launched from Visual Studio .NET.
It is worth to note the following points:
C# is case sensitive.
All statements and expression must end with a semicolon (;).
The program execution starts at the Main method.
Unlike Java, program file name could be different from the class name.
Compiling and Executing the Program:
If you are using Visual Studio.Net for compiling and executing C# programs, take the following steps:
Start Visual Studio.
On the menu bar, choose File -> New -> Project.
Choose Visual C# from templates, and then choose Windows.
Choose Console Application.
Specify a name for your project and click OK button. This creates a new project in Solution Explorer.
Write code in the Code Editor.
Click the Run button or press F5 key to execute the project. A Command Prompt window appears that contains the line Hello World.
You can compile a C# program by using the command-line instead of the Visual Studio IDE:
Open a text editor and add the above-mentioned code.
Save the file as helloworld.cs
Open the command prompt tool and go to the directory where you saved the file.
Type csc helloworld.cs and press enter to compile your code.
If there are no errors in your code, the command prompt takes you to the next line and generates helloworld.exe executable file.
Type helloworld to execute your program.
You can see the output Hello World printed on the screen.
C# is an object-oriented programming language. In Object-Oriented Programming methodology, a program consists of various objects that interact with each other by means of actions. The actions that an object may take are called methods. Objects of the same kind are said to have the same type or are said to be in the same class.
The variables in C#, are categorized into the following types:
Value types
Reference types
Pointer types
* Reference Type
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 multiple variables, 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 Type
The Object Type is the ultimate base class for all data types in C# Common Type System (CTS). Object is an alias for System.Object class. The object types can be assigned values of any other types, value types, 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; // this is boxing
*Dynamic Type
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 <variable_name> = value;
For example,
dynamic d = 20;
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 forms: quoted and @quoted.
For example,
String str = "RAJ KUMAR Point";
A @quoted string literal looks as follows:
@"TRAJ KUMR Point";
The user-defined reference types are: class, interface, or delegate. We will discuss these types in later chapter.
*Pointer Type
Pointer type variables store the memory address of another type. Pointers in C# have the same capabilities as the pointers in C or C++.
Syntax for declaring a pointer type is:
type* identifier;
We will discuss pointer types in the chapter 'Unsafe Codes'.
4.TYPE CONVERSION:
Type conversion is converting one type of data to another type. It is also known as Type Casting. In C#, type casting has two forms:
Implicit type conversion - These conversions are performed by C# in a type-safe manner. For example, conversions from smaller to larger integral types and conversions from derived classes to base classes.
Explicit type conversion - These conversions are done explicitly by users using the pre-defined functions. Explicit conversions require a cast operator.
using System;
namespace TypeConversionApplication
{
class ExplicitConversion
{
static void Main(string[] args)
{
double d = 5673.74;
int i;
// cast double to int.
i = (int)d;
Console.WriteLine(i);
Console.ReadKey();
}
}
}
========================================================
Output: 5673
C# Type Conversion Methods
C# provides the following built-in type conversion methods as described: Sr. No. Methods
1.ToBoolean: Converts a type to a Boolean value, where possible.
2.ToByte: Converts a type to a byte.
3.ToChar: Converts a type to a single Unicode character, where possible.
4.ToDateTime: Converts a type (integer or string type) to date-time structures.
5.ToDecimal: Converts a floating point or integer type to a decimal type.
6.ToDouble: Converts a type to a double type.
7.ToInt16: Converts a type to a 16-bit integer.
8.ToInt32: Converts a type to a 32-bit integer.
9.ToInt64: Converts a type to a 64-bit integer.
10.ToSbyte:Converts a type to a signed byte type.
11.ToSingle: Converts a type to a small floating point number.
12.ToString: Converts a type to a string.
13.ToType: Converts a type to a specified type.
14.ToUInt16: Converts a type to an unsigned int type.
15.ToUInt32: Converts a type to an unsigned long type.
16.ToUInt64: Converts a type to an unsigned big integer.
namespace TypeConversionApplication
{
class StringConversion
{
static void Main(string[] args)
{
int i = 75;
float f = 53.005f;
double d = 2345.7652;
bool b = true;
Console.WriteLine(i.ToString());
Console.WriteLine(f.ToString());
Console.WriteLine(d.ToString());
Console.WriteLine(b.ToString());
Console.ReadKey();
}
}
}
===============================================
Output: 75
53.005
2345.7652
True
==========================================================
Contect me to developing website with low price.
or
other specifications
C# is a modern, general-purpose, object-oriented programming language developed by Microsoft and approved by European Computer Manufacturers Association (ECMA) and International Standards Organization (ISO).
C# was developed by Anders Hejlsberg and his team during the development of .Net Framework.
C# is designed for Common Language Infrastructure (CLI), which consists of the executable code and runtime environment that allows use of various high-level languages on different computer platforms and architectures.
The following reasons make C# a widely used professional language:
It is a modern, general-purpose programming language
It is object oriented.
It is component oriented.
It is easy to learn.
It is a tructured language.
It produces efficient programs.
It can be compiled on a variety of computer platforms.
It is a part of .Net Framework.
Strong Programming Features of C#
Although C# constructs closely follow traditional high-level languages, C and C++ and being an object-oriented programming language. It has strong resemblance with Java, it has numerous strong programming features that make it endearing to a number of programmers worldwide.
Following is the list of few important features of C#:
Boolean Conditions
Automatic Garbage Collection
Standard Library
Assembly Versioning
Properties and Events
Delegates and Events Management
Easy-to-use Generics
Indexers
Conditional Compilation
Simple Multithreading
LINQ and Lambda Expressions
Integration with Windows
2. ENVIRONMENT:
The .Net framework is a revolutionary platform that helps you to write the following types of applications:
Windows applications
Web applications
Web services
The .Net framework applications are multi-platform applications. The framework has been designed in such a way that it can be used from any of the following languages: C#, C++, Visual Basic, Jscript, COBOL, etc. All these languages can access the framework as well as communicate with each other.
The .Net framework consists of an enormous library of codes used by the client languages such as C#. Following are some of the components of the .Net framework:
Common Language Runtime (CLR)
The .Net Framework Class Library
Common Language Specification
Common Type System
Metadata and Assemblies
Windows Forms
ASP.Net and ASP.Net AJAX
ADO.Net
Windows Workflow Foundation (WF)
Windows Presentation Foundation
Windows Communication Foundation (WCF)
LINQ
Integrated Development Environment (IDE) for C#
Microsoft provides the following development tools for C# programming:
Visual Studio 2010 (VS)
Visual C# 2010 Express (VCE)
Visual Web Developer
The last two are freely available from Microsoft official website. Using these tools, you can write all kinds of C# programs from simple command-line applications to more complex applications. You can also write C# source code files using a basic text editor like Notepad, and compile the code into assemblies using the command-line compiler, which is again a part of the .NET Framework.
Visual C# Express and Visual Web Developer Express edition are trimmed down versions of Visual Studio and has the same appearance. They retain most features of Visual Studio. In this tutorial, we have used Visual C# 2010 Express.
You can download it from Microsoft Visual Studio. It gets installed automatically on your machine.
Note: You need an active internet connection for installing the express edition.
3. PROGRAM STRUCTURE:
Before we study basic building blocks of the C# programming language, let us look at a bare minimum C# program structure so that we can take it as a reference in upcoming chapters.
Creating Hello World Program
A C# program consists of the following parts:
Namespace declaration
A class
Class methods
Class attributes
A Main method
Statements and Expressions
Comments
Let us look at a simple code that prints the words "Hello World":
using System;
namespace HelloWorldApplication
{
class HelloWorld
{
static void Main(string[] args)
{
/* my first program in C# */
Console.WriteLine("Hello World");
Console.ReadKey();
}
}
}
===========================================================
Out put : Hello World
Let us look at the various parts of the given program:
The first line of the program using System; - the using keyword is used to include the System namespace in the program. A program generally has multiple using statements.
The next line has the namespace declaration. A namespace is a collection of classes. The HelloWorldApplication namespace contains the class HelloWorld.
The next line has a class declaration, the class HelloWorld contains the data and method definitions that your program uses. Classes generally contain multiple methods. Methods define the behavior of the class. However, the HelloWorld class has only one method Main.
The next line defines the Main method, which is the entry point for all C# programs. The Main method states what the class does when executed.
The next line /*...*/ is ignored by the compiler and it is put to add comments in the program.
The Main method specifies its behavior with the statement Console.WriteLine("Hello World");
WriteLine is a method of the Console class defined in the System namespace. This statement causes the message "Hello, World!" to be displayed on the screen.
The last line Console.ReadKey(); is for the VS.NET Users. This makes the program wait for a key press and it prevents the screen from running and closing quickly when the program is launched from Visual Studio .NET.
It is worth to note the following points:
C# is case sensitive.
All statements and expression must end with a semicolon (;).
The program execution starts at the Main method.
Unlike Java, program file name could be different from the class name.
Compiling and Executing the Program:
If you are using Visual Studio.Net for compiling and executing C# programs, take the following steps:
Start Visual Studio.
On the menu bar, choose File -> New -> Project.
Choose Visual C# from templates, and then choose Windows.
Choose Console Application.
Specify a name for your project and click OK button. This creates a new project in Solution Explorer.
Write code in the Code Editor.
Click the Run button or press F5 key to execute the project. A Command Prompt window appears that contains the line Hello World.
You can compile a C# program by using the command-line instead of the Visual Studio IDE:
Open a text editor and add the above-mentioned code.
Save the file as helloworld.cs
Open the command prompt tool and go to the directory where you saved the file.
Type csc helloworld.cs and press enter to compile your code.
If there are no errors in your code, the command prompt takes you to the next line and generates helloworld.exe executable file.
Type helloworld to execute your program.
You can see the output Hello World printed on the screen.
C# is an object-oriented programming language. In Object-Oriented Programming methodology, a program consists of various objects that interact with each other by means of actions. The actions that an object may take are called methods. Objects of the same kind are said to have the same type or are said to be in the same class.
The variables in C#, are categorized into the following types:
Value types
Reference types
Pointer types
* Reference Type
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 multiple variables, 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 Type
The Object Type is the ultimate base class for all data types in C# Common Type System (CTS). Object is an alias for System.Object class. The object types can be assigned values of any other types, value types, 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; // this is boxing
*Dynamic Type
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 <variable_name> = value;
For example,
dynamic d = 20;
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 forms: quoted and @quoted.
For example,
String str = "RAJ KUMAR Point";
A @quoted string literal looks as follows:
@"TRAJ KUMR Point";
The user-defined reference types are: class, interface, or delegate. We will discuss these types in later chapter.
*Pointer Type
Pointer type variables store the memory address of another type. Pointers in C# have the same capabilities as the pointers in C or C++.
Syntax for declaring a pointer type is:
type* identifier;
We will discuss pointer types in the chapter 'Unsafe Codes'.
4.TYPE CONVERSION:
Type conversion is converting one type of data to another type. It is also known as Type Casting. In C#, type casting has two forms:
Implicit type conversion - These conversions are performed by C# in a type-safe manner. For example, conversions from smaller to larger integral types and conversions from derived classes to base classes.
Explicit type conversion - These conversions are done explicitly by users using the pre-defined functions. Explicit conversions require a cast operator.
using System;
namespace TypeConversionApplication
{
class ExplicitConversion
{
static void Main(string[] args)
{
double d = 5673.74;
int i;
// cast double to int.
i = (int)d;
Console.WriteLine(i);
Console.ReadKey();
}
}
}
========================================================
Output: 5673
C# Type Conversion Methods
C# provides the following built-in type conversion methods as described: Sr. No. Methods
1.ToBoolean: Converts a type to a Boolean value, where possible.
2.ToByte: Converts a type to a byte.
3.ToChar: Converts a type to a single Unicode character, where possible.
4.ToDateTime: Converts a type (integer or string type) to date-time structures.
5.ToDecimal: Converts a floating point or integer type to a decimal type.
6.ToDouble: Converts a type to a double type.
7.ToInt16: Converts a type to a 16-bit integer.
8.ToInt32: Converts a type to a 32-bit integer.
9.ToInt64: Converts a type to a 64-bit integer.
10.ToSbyte:Converts a type to a signed byte type.
11.ToSingle: Converts a type to a small floating point number.
12.ToString: Converts a type to a string.
13.ToType: Converts a type to a specified type.
14.ToUInt16: Converts a type to an unsigned int type.
15.ToUInt32: Converts a type to an unsigned long type.
16.ToUInt64: Converts a type to an unsigned big integer.
namespace TypeConversionApplication
{
class StringConversion
{
static void Main(string[] args)
{
int i = 75;
float f = 53.005f;
double d = 2345.7652;
bool b = true;
Console.WriteLine(i.ToString());
Console.WriteLine(f.ToString());
Console.WriteLine(d.ToString());
Console.WriteLine(b.ToString());
Console.ReadKey();
}
}
}
===============================================
Output: 75
53.005
2345.7652
True
==========================================================
Contue reading nd learning see it
===========================================================Contect me to developing website with low price.
or
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| RAJ KUMAR (Software Engg) |
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