“Identifiers are names that programmers choose for their classes, methods, variables, and so on. Here are the identifiers in our example program, in the order in which they appear:

System x Console WriteLine

“An identifier must be a whole word, essentially made up of Unicode characters starting with a letter or underscore. C# identifiers are case sensitive. By convention, parameters, local variables, and private fields should be in camel case (e.g., myVariable), and all other identifiers should be in Pascal case (e.g., MyMethod).” (Fair Use B08SYWWDTX)

“Keywords are names that mean something special to the compiler. These are two keywords in our example program, using and int.” (Fair Use B08SYWWDTX)

Most keywords are reserved, which means that you can’t use them as identifiers. Here is the full list of C# reserved keywords:

• abstract

• as

• base

• bool

• break

• byte

• case

• catch

• char

• checked

• class

• const

• continue

• decimal

• default

• delegate

• do

• double

• else

• enum

• event

• explicit

• extern

• false

• finally

• fixed

• float

• for

• foreach

• goto

• if

• implicit

• in

• int

• interface

• internal

• is

• lock

• long

• namespace

• new

• null

• object

• operator

• out

• override

• params

• private

• protected

• public

• readonly

• ref

• return

• sbyte

• sealed

• short

• sizeof

• stackalloc

• static

• string

• struct

• switch

• this

• throw

• true

• try

• typeof

• uint

• ulong

• unchecked

• unsafe

• ushort

• using

• virtual

• void

• while

(Fair Use B08SYWWDTX)