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Double.IsNaN Method

Returns a value that indicates whether the specified value is not a number (NaN).

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

public static bool IsNaN(
	double d
)

Parameters

d
Type: System.Double

A double-precision floating-point number.

Return Value

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

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.

NoteNote

IsNaN returns false if a Double value is either PositiveInfinity or NegativeInfinity. To test for these values, use the IsInfinity, IsPositiveInfinity, and IsNegativeInfinity methods.

The following code example illustrates the use of IsNaN:

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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