C# is an object-oriented, component-oriented, and general-purpose programming language that is easy to learn and produces efficient programs. It allows code to be compiled on a variety of computer platforms and is part of the .NET Framework. Namespaces are used to organize code into collections of classes, interfaces, structs, enums, and delegates. The Main method is the entry point for a C# application and allows writing output to the console. There are two ways to write to the console: concatenation by combining strings, and placeholder syntax which is preferred.

1. C# class INTRODUCTION

2. What is C#?
• C# is a simple, modern, general-purpose, object-oriented programming language
• Reasons make C# a widely used professional language –
• It is a modern, general-purpose programming language
• It is object oriented.
• It is component oriented.
• It is easy to learn.
• It is a structured language.
• It produces efficient programs.
• It can be compiled on a variety of computer platforms.
• It is a part of .NET Framework.

3. What is Namespace?
• A namespace is used to organize your code and is a collection of classes, interfaces, structs,
Enums and delegates.
• Namespace Declaration:
• The namespace declaration. using System, indicates that you are using The System namespace.
Example:
//Namespace Declaration
using System;

4. Purpose of Main method
• Main method is the entry point into your application.
//Namespace Declaration
using System;
namespace Introduction
{
class Program
{
static void Main(string[]args)
{
//C# Tutorial - Introduction
//Write toconsole
Console.WriteLine("Welcome toC#Training!");
Main1();
}
static void Main1()
{
Console.WriteLine("Welcome toC#Training 1!");
}
}
}

5. Reading and writing to a console
Reading from the console:
Example:
//Read the string from console
var username= Console.ReadLine();
//Read theint fromconsole
int userNumber= int.Parse(Console.ReadLine());
Writing to the console:
Example:
//Prompt the user for his name
Console.WriteLine("Please enteryour name");

6. 2 ways to write to console:
Concatenation
Example:
//Concatenatenamewith hello word and print
Console.WriteLine("Hello "+ username);
Plate Holder syntax - Most Preferred
Example:
//Placeholder syntax to print namewith hello word -Most Preferred
Console.WriteLine("Hello {0}",username);
Console.WriteLine("Hello {0}{1}",firstname, lastname);