Keywords and Operators

C# keywords are reserved words with special meaning in C# programs. C# also has several operators for performing bitwise, logical, and mathematical operations. Those familiar with C, C++, or Java will recognize the similarities of these operators. Also, note that C# is case sensitive. The fields (variables) myInt and MyInt are two distinct identifiers, and whereas double is a keyword, Double is a valid variable name.

C# Keywords

Table 2.2 shows all the keywords available for C#. Although C# keywords may not be used as identifiers (variable and type names), an exception to this rule is if the keyword were prefixed with an @ symbol. Although I wouldn't recommend it, @if and other keywords prefixed with @ could be used as identifiers.

Table 2.2. Complete List of C# 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
volatile	while

Most of the keywords in Table 2.2 will be used throughout this book, and I'll explain each one when it is applicable. Full coverage of every keyword is beyond the scope of this book.

C# Operators

The C# operators, shown in Table 2.3, are very similar to those of C, C++, and Java. They offer the ability to create bitwise, logical, and mathematical operations.

Table 2.3. Operator Precedence and Associativity

OPERATORS	ASSOCIATIVITY
x.y f(x) a[x] x++ x-- new typeof checked unchecked	Left
+(unary) -(unary) ! ~ ++x --x (T)x	Left
* / %	Left
+(arithmetic) -(arithmetic)	Left
<< >>	Left
< > <= >= is as	Left
== !=	Left
&	Left
^	Left
|	Left
&&	Left
||	Left
?:	Right
= *= /= %= += -= <<= >>= &= ^= |=	Right