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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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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