C# - Basic Program Structure

C# is a modern programming language developed by Anders Hejlsberg and his team during the development of .Net Framework and approved by Ecma and ISO.

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 to be used on different computer platforms.

The following reasons make C# a widely used professional language:

Ø  Modern, general-purpose programming language

Ø  Structured language

Ø  Object oriented

Ø  Component oriented

Ø  Easy to learn

Ø  It produces efficient programs

Ø  It can be compiled on a variety of computer platforms

Ø  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 multitude of programmers worldwide.

Following is the list of few important features:

Ø  Automatic Garbage Collection

Ø   Standard Library

Ø  Boolean Conditions

Ø  Assembly Versioning

Ø  Properties and Events

Ø  Delegates and Events Management

Ø  Conditional Compilation

Ø   Indexers

Ø  Simple Multithreading

Ø  Easy-to-use Generics

Ø  LINQ and Lambda Expressions

C# - Program Structure

A C# program basically consists of the following parts:

Ø  Namespace declaration

Ø   A class

Ø  Class methods

Ø   Class attributes

Ø   A Main method

Ø   Statements & Expressions

Ø  Comments

While writing a C# Programs, we have to keep following points in mind

Ø  C# is case sensitive.

Ø  All statements and expression must end with a semicolon (;).

Ø  The program execution starts at the Main method.

Ø  File name could be different from the class name.

Let us Consider Simple C# Program to understand more about structure and how to write C# program

using System;

namespace PrintMyNameApp

{

   class PrintMyName

   {

      static void Main(string[] args)

      {

         /* my first program in C# */

         Console.WriteLine("My Name is Dhananjay");

         Console.ReadKey();

      }

   }

}

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

“My Name is Dhananjay”

Now discuss various parts of the above program:

Ø  The first line of the program using System; -using is a keyword and System is namespace.  The using keyword is used to include the System namespace in the program.

A program generally has multiple using statements.

Ø  The next line has the namespace declaration. A namespace is a collection of classes.

 The PrintMyNameApp namespace contains the class PrintMyName.

Ø  The next line has a class declaration, the class PrintMyName  contains the data and method definitions that your program uses. Classes generally would contain more than one method. Methods define the behavior of the class.

However, the PrintMyName  class has only one method Main.

Ø  The next line defines the Main method, which is the entry point for all C# programs. The Main method states what the class will do when executed.

Ø  The next line /*...*/ will be ignored by the compiler and it has been put to add additional comments in the program.

Ø  The Main method specifies its behavior with the statement Console.WriteLine("My Name is Dhananjay");

Ø   WriteLine is a method of the Console class defined in the System namespace. This statement causes the message " My Name is Dhananjay!" to be displayed on the screen.

Ø  The last line Console.ReadKey();  which makes the program wait for a key press and it prevents the screen from running and closing quickly.

Compile & Execute a C# Program:

C# Program can be Compile from Visual Studio IDE OR Using Command Line

Steps For compiling and executing C# programs using Visual Studio IDE

Ø  Start Visual Studio.

Ø   From the menu bar, choose File, New, Project.

Ø   Choose Visual C# from templates, Windows, Console Application.

Ø   Specify a name for your project, and then choose the OK button.

Ø   The new project appears in Solution Explorer.

Ø   Write code in the Code Editor.

                Click the Run button or the F5 key to run the project.

Steps For compiling and executing C# programs using Command Line

Ø Open a text editor and add the above-mentioned code.

Ø Save the file as PrintMyName.cs

Ø Open the command prompt tool and go to the directory where you saved the file.

Ø  Type csc PrintMyName.cs and press enter to compile your code.

Ø  If there are no errors in your code, the command prompt will take you to the next line and would generate PrintMyName.exe executable file, where your code file is saved.

Ø Next, type PrintMyName to execute your program.

Ø You will be able to see "My Name is Dhananjay" printed on the screen.