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();
}
}
}

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

Hello World

 

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.