Hello World!

C# Hello World - Your First C# Program

C# is a simple, modern, general-purpose, object-oriented programming language developed by Microsoft within its .NET initiative led by Anders Hejlsberg.

In this tutorial, we will learn how to write a simple “Hello World!” program in C#. This will get you familiar with the basic syntax and requirements of a C# program.

The “Hello World!” program is often the first program we see when we dive into a new language. It simply prints Hello World! on the output screen.

The purpose of this program is to get us familiar with the basic syntax and requirements of a programming language.

“Hello World!” in C#

// Hello World! program
namespace HelloWorld
{
    class Hello {         
        static void Main(string[] args)
        {
            System.Console.WriteLine("Hello World!");
        }
    }
}

When you run the program, the output will be:

Hello World!

How the “Hello World!” program in C# works?

Let’s break down the program line by line.

1. // Hello World! Program

   // indicates the beginning of a comment in C#. Comments are not executed by the C# compiler.They are intended for the developers to better understand a piece of code.

2. namespace HelloWorld{...}

   The namespace keyword is used to define our own namespace. Here we are creating a namespace called HelloWorld.

   Just think of namespace as a container which consists of classes, methods and other namespaces.

3. class Hello{...}

   The above statement creates a class named - Hello in C#. Since, C# is an object-oriented programming language, creating a class is mandatory for the program’s execution.

4. static void Main(string[] args){...}

   Main() is a method of class Hello. The execution of every C# program starts from the Main() method. So it is mandatory for a C# program to have a Main() method.

   The signature/syntax of the Main() method is:

   static void Main(string[] args){
       ...
   }
   

5. System.Console.WriteLine("Hello World!");

   Here WriteLine() is a method of the Console class defined in the System namespace.

Alternative Hello World! implementation

Here’s an alternative way to write the “Hello World!” program.

// Hello World! program
using System;

namespace HelloWorld
{
    class Hello {         
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}

Notice in this case, we’ve written using System; at the start of the program. By using this, we can now replace

System.Console.WriteLine("Hello World!");

with

Console.WriteLine("Hello World!");

This is a convenience we’ll be using in our later problems as well.

Task

Now that we have learned the basics of our code. Let’s solve a example in the editor below.

Write a code to print “Hello, InterviewBit!” (without quotes) in the editor below.