Double.IsNaN Method (System)

.NET Framework Class Library

Double..::.IsNaN Method

Returns a value indicating whether the specified number evaluates to a value that is not a number (NaN).

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public Shared Function IsNaN ( _
    d As Double _
) As Boolean

Visual Basic (Usage)

Dim d As Double
Dim returnValue As Boolean

returnValue = Double.IsNaN(d)

public static bool IsNaN(
    double d
)

Visual C++

public:
static bool IsNaN(
    double d
)

JScript

public static function IsNaN(
    d : double
) : boolean

Parameters

d: Type: System..::.Double
A double-precision floating-point number.

Return Value

Type: System..::.Boolean
true if d evaluates to NaN; otherwise, false.

Remarks

Floating-point operations return NaN to signal that that result of the operation is undefined. For example, dividing 0.0 by 0.0 results in NaN.

Examples

The following code example illustrates the use of IsNaN:

Visual Basic

' This will return true.
If Double.IsNaN(0 / zero) Then
    Console.WriteLine("Double.IsNan() can determine whether a value is not-a-number.")
End If

            // This will return true.
            if (Double.IsNaN(0 / zero)) 
            {
                Console.WriteLine("Double.IsNan() can determine whether a value is not-a-number.");
            }

Visual C++

// This will return true.
if ( Double::IsNaN( 0 / zero ) )
{
   Console::WriteLine( "Double::IsNan() can determine whether a value is not-a-number." );
}

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference