Double.IsNaN(Double) Method

Reference

Definition

Namespace:: System

Assemblies:: mscorlib.dll, System.Runtime.dll

Assemblies:: netstandard.dll, System.Runtime.dll

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Double.cs

Source:: Double.cs

Source:: Double.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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

public:
 static bool IsNaN(double d);

public:
 static bool IsNaN(double d) = System::Numerics::INumberBase<double>::IsNaN;

public static bool IsNaN(double d);

static member IsNaN : double -> bool

Public Shared Function IsNaN (d As Double) As Boolean

Parameters

d: Double

A double-precision floating-point number.

Returns

Boolean

true if d evaluates to NaN; otherwise, false.

Implements

IsNaN(TSelf)

Examples

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." );
}

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

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

' 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

Remarks

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

Note

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

Applies to

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP	10.0

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