C# Basic Example – HelloWorld

Basic Program to Understand C# Program Structure.

Program.cs

using System;

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

What do we have in this C# HelloWorld program?

1. Imports

We can import other namespaces and use them in our program.

using System

In here, we are importing System namespace with using keyword.

2. Namespace

Namespace is a collection of collection of classes and sub namespaces. These sub namespaces are also namespaces in their own scope, but may have to be referenced using the parent namespace.

namespace HelloWorld
 {

 }

namespace is the keyword used to define a namespacec. HelloWorld is the name of the namespace by which we can refer to. And this namespace has a class inside it.

3. class Definition

A class is a piece of code that defines how a class of objects should behave, and what properties they can have.

class Program
 {

 }

class is the keyword that defines a class, followed by the class name Program.

4. Method Definition

Method is a logical representation of a behavior. Methods can be used to create functionalities for a class. A method can have a scope, the type of data it returns, a name to be referenced from other code, list of arguments that it can take.

A method takes in argument(s), not mandatory, and transforms them to return an output or change the state of program or file system or anything that it can get access to.

static void Main(string[] args)
 {

 }

In this example, the scope of this function is declared as static. Return type void, meaning it returns nothing. The name that one has to use to access this method is Main. And it receives a String array as an argument.

5. Function Body

Function body is a set of statements. These could contain print statements, conditional statements, looping statements, or statements that could call other functions, etc.

Console.WriteLine("Hello World!");

In this example, we are saying ‘Hello World!’ by printing it in the Console.