Writing the first program

class FirstProgram
{
  static void Main()
   {
      System.Console.WriteLine("My first program in csharp..!");
    }
}

output:  My first program in csharp..!

Note: To compile the program we need 'Developer Command Prompt for VS' which we will get automatically after installing visual studio.

What is System.Console.WriteLine ?

•  Console is a predefined class under the libraries of our language which provides with a set of static members to perform IO operations on standard I/O devices.
• The Console class contains methods like WriteLine, Write, ReadLine, Read, ReadKey to perform I/O operations.
• System is a namespace where a namespace is a logical container of types like Class, Structure, Interface, Enum and Delegate.

What is Namespace?

• Namespaces are used as logical containers in programming languages. 
• Every predefined type in our libraries is under some namespace.
• We can also define our types under some namespaces and we will check out that process later.
• If a type is defined under any namespace then it is must to prefix with that particular namespace while consuming that type.
•  To overcome the above problem we provided with an option known as importing a namespace with the help of "using directive".
• If we import a namespace into the program we can start consuming all the types under that namespace without prefixing it each and every time.

Example: using System;

Now the program can be written as, 

using System;

class FirstProgram
{
  static void Main()
   {
      Console.WriteLine("My first program in csharp..!");
    }
}