Words reserved in C# (Keywords)

Some words have special meaning for the compiler C#. These can’t are using how identifiers, at least that using the “@” before of same.
Ex.: @if is an identifier accepts, but IF don’t, because is an word reserved.
WORS RESERVED IN C#:

abstract	event	new	struct
as	explicit	null	switch
base	extern	object	this
bool	false	operator	throw
break	finally	out	true
byte	fixed	override	try
case	float	params	typeof
catch	for	private	uint
char	foreach	protected	ulong
checked	goto	public	unchecked
class	if	readonly	unsafe
const	implicit	ref	ushort
continue	in	return	using
decimal	int	sbyte	virtual
default	interface	sealed	volatile
delegate	internal	short	void
do	is	sizeof	while
double	lock	stackalloc
else	long	static
enum	namespace	string

Decision Making: Equality and relational operators

This section introduces C#’s if structure, wich allows a program to make a decision based on the truth or falsity of some condition. If the condition is met (i.e., the condition is true), the statement in the body of the if structures executes. If the condition is not met (i.e., the condition is false), the body statement does not execute.

Standart algebraic equality operator or relational operator	C# equality or relational operator	Example of C# condition	Meaning of C# condition
=	==	X == y	X is equal to y
≠	!=	X != y	X is not equal to y
>	>	X > y	X is greater than y
<	<	X < y	X is less than y
≥	>=	X >= y	X is greater than or equal to y
≤	<=	X <=y	X is less than or equal to y

Sources:  C# for experienced programmers – Deitel Developers series