The Hello World Program is the most basic program when we dive into a new programming language. This simply prints "Hello World!" on the console. In C#, a basic program consists of the following:

• A Namespace Declaration
• Class Declaration & Definition
• Class Members(like variables, methods, etc.)
• Main Method
• Statements or Expressions

Example: Hello World program in C#.

using System; 

namespace HelloWorldApp { 
    
    class Geeks { 
        
        static void Main(string[] args) { 
            
            // statement printing Hello World! 
            Console.WriteLine("Hello World!"); 
            
            // To prevent the screen from running and closing quickly 
            Console.ReadKey(); 
        } 
    } 
} 

using System; 

​

namespace HelloWorldApp { 

    class Geeks { 

        static void Main(string[] args) { 

            // statement printing Hello World! 

            Console.WriteLine("Hello World!"); 

            // To prevent the screen from running and closing quickly 

            Console.ReadKey(); 

        } 

    } 

}

Hello World!

Explanation:

This program is a simple C# console application that prints Hello World to the screen. Every C# program starts execution from the Main method.

• using System: allows access to built-in classes like Console.
• namespace HelloWorldApp: groups the class logically under a namespace.

Inside the namespace, we define a class Geeks which contains the Main method. The Main method is special because it acts as the entry point for the program.

• Console.WriteLine("Hello World!"): prints text to the console.
• Console.ReadKey(): waits for a key press so the program doesn’t close immediately.

Executing C# Program

There are generally three ways to compile and execute a C# program.

• Online Compiler: Run C# programs directly in a browser without installation.
• IDE (Visual Studio): Microsoft’s powerful IDE with built-in tools for C# development.
• Command Line: Install the .NET SDK to compile and run C# programs locally.

Now follow the below steps:

Step 1: Open a command prompt and create an empty .NET project using the following command:

dotnet new console -o <Project-Name>

In <Project-Name>, specify the desired project name (e.g., HelloWorld). This command creates an empty project template with all required packages to run a .NET project.

This is the complete folder structure which is created using the above command.

Program.cs is the entry point of a C# project where the main code is written. It can be opened in IDEs like Visual Studio or VS Code and contains the default starter code for the application.

This is a simple program we can run it using the following command mentioned in the below steps.

Step 2: Now we need to build the project using the command mentioned below.

Navigate to the project directory:

cd HelloWorld

Build the project using:

dotnet build

Step 3: Now to see the output run the command mentioned below.

dotnet run

This will execute the default Program.cs file and display output in the console.