C# 0 The Complete Reference

System

, itself.

The Members of System

In addition to a large number of exception classes, 

System

 contains the following classes:

ActivationContext Activator

AppDomain

AppDomainManager AppDomainSetup

ApplicationId

ApplicationIdentity Array

AssemblyLoadEventArgs

Attribute

AttributeUsageAttribute

BitConver ter

Buffer

CharEnumerator

CLSCompliantAttribute

Console

ConsoleCancelEventArgs ContextBoundObject

ContextStaticAttribute

Conver t

DBNull

Delegate

Enum

Environment

EventArgs

Exception

FileStyleUriParser 

FlagsAttribute

FtpStyleUriParser GC

GenericUriParser GopherStyleUriParser 

HttpStyleUriParser

LdapStyleUriParser LoaderOptimizationAttribute

LocalDataStoreSlot

MarshalByRefObject

Math

MTAThreadAttribute

MulticastDelegate

NetPipeStyleUriParser NetTcpStyleUriParser 

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NewsStyleUriParser NonSerializedAttribute

Nullable

Object

ObsoleteAttribute

OperatingSystem

ParamArrayAttribute

Random

ResolveEventArgs

SerializableAttribute

STAThreadAttribute

String

StringComparer

ThreadStaticAttribute

TimeZone

TimeZoneInfo TimeZoneInfo.AdjustmentRule 

Type

UnhandledExceptionEventArgs

Uri

UriBuilder

UriParser

UriTemplate UriTemplateEquivalenceComparer 

UriTemplateTable UriTypeConver ter ValueType

Version

WeakReference

System

 defines the following structures:

ArgIterator

ArraySegment Boolean

Byte

Char

ConsoleKeyInfo 

DateTime

DateTimeOffset

Decimal

Double

Guid

Int16

Int32

Int64

IntPtr

ModuleHandle

Nullable RuntimeArgumentHandle

RuntimeFieldHandle

RuntimeMethodHandle

RuntimeTypeHandle

Sbyte

Single

TimeSpan

TimeZoneInfo.TransitionTime TypedReference

UInt16

UInt32

UInt64

UIntPtr

Void

System

 defines the following interfaces:

_AppDomain

IAppDomainSetup

IAsyncResult

ICloneable

IComparable

IComparable

IConver tible ICustomFormatter

IDisposable

IEquatable IFormatProvider

IFormattable

ISer viceProvider

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System

 defines the following delegates:

Action

Action Action

T2> 

Action 

Action 

AppDomainInitializer

AssemblyLoadEventHandler

AsyncCallback

Comparison 

ConsoleCancelEventHandler

Conver ter 

CrossAppDomainDelegate

EventHandler

EventHandler Func

Func 

Func 

Func 

Func 

Predicate 

ResolveEventHandler

UnhandledExceptionEventHandler

System

 defines these enumerations:

ActivationContext.contextForm AppDomainManagerInitializationOptions AttributeTargets

Base64FormattingOptions ConsoleColor

ConsoleKey

ConsoleModifiers

ConsoleSpecialKey

DateTimeKind 

DayOfWeek

Environment.SpecialFolder

EnvironmentVariableTarget 

GCCollectionMode

GenericUriParserOptions

LoaderOptimization

MidpointRounding

PlatformID

StringComparison 

StringSplitOptions TypeCode

UriComponents 

UriFormat UriHostNameType

UriIdnScope

UriKind UriPar tial

As the preceding tables show, 

System

 is quite large. It is not possible to examine all of 

its constituents in detail in a single chapter. Furthermore, several of 

System

’s members, such 

as

Nullable

,

Type

,

Exception

, and 

Attribute

, are discussed in Part I or elsewhere in 

Part II. Finally, because 

System

.

String

, which defines the C# 

string

 type, is such a large and 

important topic, it is covered in Chapter 22 along with formatting. For these reasons, this 

chapter explores only those members that are most commonly used by C# programmers 

and that are not fully covered elsewhere.

The Math Class

Math

 defines several standard mathematical operations, such as square root, sine, cosine, 

and logarithms. The 

Math

 class is 

static

, which means all of the methods defined by 

Math

are 

static

 and no object of type 

Math

 can be constructed. It also means 

Math

 is implicitly 

sealed and cannot be inherited. The methods defined by 

Math

 are shown in Table 21-1. All 

angles are in radians.

Math

 also defines these two fields:

public const double E

public const double PI

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E

 is the value of the natural logarithm base, commonly referred to as 

e.

PI

 is the value of pi.

Method

Meaning

public static double Abs(double 

v

)

Returns the absolute value of 

v.

public static float Abs(float 

v

)

Returns the absolute value of 

v.

public static decimal Abs(decimal 

v

)

Returns the absolute value of 

v.

public static int Abs(int 

v

)

Returns the absolute value of 

v.

public static shor t Abs(shor t 

v

)

Returns the absolute value of 

v.

public static long Abs(long 

v

)

Returns the absolute value of 

v.

public static sbyte Abs(sbyte 

v

)

Returns the absolute value of 

v.

public static double Acos(double 

v

)

Returns the arc cosine of 

v.

 The value of 

v

 must be 

between –1 and 1.

public static double Asin(double 

v

)

Returns the arc sine of 

v.

 The value of 

v

 must be 

between –1 and 1.

public static double Atan(double 

v

)

Returns the arc tangent of 

v.

public static double Atan2(double 

y

,

                                       double 

x

)

Returns the arc tangent of 

y

/

x.

public static long BigMul(int 

x

, int 

y

)

Returns the result of 

x

 * 

y

as a 

long

 value, thus 

avoiding over flow.

public static double Ceiling(double 

v

)

Returns the smallest integer (represented as a 

floating-point value) not less than 

v.

 For example, 

given 1.02, 

Ceiling( )

 returns 2.0. Given –1.02, 

Ceiling( )

 returns –1.

public static double Ceiling(decimal 

v

)

Returns the smallest integer (represented as a 

decimal value) not less than 

v.

 For example, given 

1.02,

Ceiling( )

 returns 2.0. Given –1.02, 

Ceiling( ) 

returns –1. 

public static double Cos(double 

v

)

Returns the cosine of 

v.

public static double Cosh(double 

v

)

Returns the hyperbolic cosine of 

v.

public static int DivRem(int 

x

, int 

y

,

                                   out int 

rem

)

Return the result of 

x

 / 

y.

 The remainder is returned 

in

rem.

public static long DivRem(long 

x

, long 

y

,

                                     out long 

rem

)

Return the result of 

x

 / 

y.

 The remainder is returned 

in

rem.

public static double Exp(double 

v

)

Returns the natural logarithm base 

e

 raised to the 

v

power.

public static decimal Floor(decimal 

v

)

Returns the largest integer (represented as a decimal 

value) not greater than 

v.

 For example, given 1.02, 

Floor( )

 returns 1.0. Given –1.02, 

Floor( )

 returns –2.

T

ABLE

 21-1 

Methods Defi ned by 

Math

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619

public static double Floor(double 

v

)

Returns the largest integer (represented as a floating-

point value) not greater than 

v.

 For example, given 

1.02,

Floor( )

 returns 1.0. Given –1.02, 

Floor( )

returns –2. 

public static double

    IEEERemainder(double 

dividend

,

                           double 

divisor

)

Returns the remainder of 

dividend

 / 

divisor.

public static double Log(double 

v

)

Returns the natural logarithm for 

v.

public static double Log(double 

v

,

                                     double 

base

)

Returns the logarithm for 

v

 using base 

base.

public static double Log10(double 

v

)

Returns the base 10 logarithm for 

v.

public static double Max(double 

v1

,

                                     double

 v2

)

Returns the greater of 

v1

 and 

v2.

public static float Max(float 

v1,

 float 

v2

)

Returns the greater of 

v1

 and 

v2.

public static decimal Max(decimal 

v1

,

                                     decimal 

v2

)

Returns the greater of 

v1

 and 

v2.

public static int Max(int 

v1

, int 

v2

)

Returns the greater of 

v1

 and 

v2.

public static shor t Max(shor t 

v1

, shor t 

v2

)

Returns the greater of 

v1

 and 

v2.

public static long Max(long 

v1

, long 

v2

)

Returns the greater of 

v1

 and 

v2.

public static uint Max(uint 

v1

, uint 

v2

)

Returns the greater of 

v1

 and 

v2.

public static ushor t Max(ushor t 

v1

,

                                    ushor t 

v2

)

Returns the greater of 

v1

 and 

v2.

public static ulong Max(ulong 

v1

,

                                   ulong 

v2

)

Returns the greater of 

v1

 and 

v2.

public static byte Max(byte 

v1

, byte 

v2

)

Returns the greater of 

v1

 and 

v2.

public static sbyte Max(sbyte 

v1

, sbyte 

v2

)

Returns the greater of 

v1

 and 

v2.

public static double Min(double 

v1

,

                                    double

 v2

)

Returns the lesser of 

v1

 and 

v2.

public static float Min(float 

v1

, float 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static decimal Min(decimal 

v1

,

                                     decimal 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static int Min(int 

v1

, int 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static shor t Min(shor t 

v1

, shor t 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static long Min(long 

v1

, long 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static uint Min(uint 

v1

, uint 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static ushor t Min(ushor t 

v1

,

                                    ushor t 

v2

)

Returns the lesser of 

v1

 and 

v2.

T

ABLE

 21-1 

Methods Defi ned by 

Math

(continued)

Method

Meaning

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public static ulong Min(ulong 

v1

, ulong 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static byte Min(byte 

v1

, byte 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static sbyte Min(sbyte 

v1

, sbyte 

v2

)

Returns the lesser of 

v1

 and 

v2.

public static double Pow(double 

base

,

                                     double 

exp

)

Returns 

base

 raised to the 

exp

 power(

base

exp

).

public static double Round(double 

v

)

Returns 

v

 rounded to the nearest whole number.

public static decimal Round(decimal 

v

)

Returns 

v

 rounded to the nearest whole number.

public static double Round(double 

v

,

                                       int 

frac

)

Returns 

v

 rounded to the number of fractional digits 

specified by 

frac.

public static decimal Round(decimal 

v

,

                                         int 

frac

)

Returns 

v

 rounded to the number of fractional digits 

specified by 

frac.

public static double Round(double 

v

,

                       MidpointRounding 

how

)

Returns 

v

 rounded to the nearest whole number using 

the rounding mode specified by 

how.

public static decimal Round(decimal 

v

,

                         MidpointRounding 

how

)

Returns 

v

 rounded to the nearest whole number using 

the rounding mode specified by 

how.

public static double Round(double 

v

,

                                        int 

frac

,

                 MidpointRounding 

how

)

Returns 

v

 rounded to the number of fractional digits 

specified by 

frac.

 It uses the rounding mode specified 

by

how.

public static decimal Round(decimal 

v

,

                                         int 

frac

,

                  MidpointRounding 

how

)

Returns 

v

 rounded to the number of fractional digits 

specified by 

frac.

 It uses the rounding mode specified 

by

how.

public static int Sign(double 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero.

public static int Sign(float 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero.

public static int Sign(decimal 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero. 

public static int Sign(int 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero.

public static int Sign(shor t 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero.

public static int Sign(long 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero. 

public static int Sign(sbyte 

v

)

Returns –1 if 

v

 is less than zero, 0 if 

v

 is zero, and 

1 if 

v

 is greater than zero. 

public static double Sin(double 

v

)

Returns the sine of 

v.

public static double Sinh(double 

v

)

Returns the hyperbolic sine of 

v.

Method

Meaning

T

ABLE

 21-1 

Methods Defi ned by 

Math

(continued)

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