Double.NaN Field (System)

.NET Framework Class Library

Double..::.NaN Field

Represents a value that is not a number (NaN). This field is constant.

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

Syntax

Visual Basic (Declaration)

Public Const NaN As Double

Visual Basic (Usage)

Dim value As Double

value = Double.NaN

public const double NaN

Visual C++

public:
literal double NaN

JScript

public const var NaN : double

Remarks

The value of this constant is the result of dividing zero by zero.

This constant is returned when the result of an operation is undefined.

Use IsNaN to determine whether a value is not a number. It is not possible to determine whether a value is not a number by comparing it to another value equal to NaN.

Examples

The following code example illustrates the use of NaN:

Visual Basic

Dim zero As Double = 0

' This condition will return false.
If (0 / zero) = Double.NaN Then
    Console.WriteLine("0 / 0 can be tested with Double.NaN.")
Else
    Console.WriteLine("0 / 0 cannot be tested with Double.NaN; use Double.IsNan() instead.")
End If

            Double zero = 0;
            
            // This condition will return false.
            if ((0 / zero) == Double.NaN) 
            {
                Console.WriteLine("0 / 0 can be tested with Double.NaN.");
            } 
            else 
            {
                Console.WriteLine("0 / 0 cannot be tested with Double.NaN; use Double.IsNan() instead.");
            }

Visual C++

Double zero = 0;

// This condition will return false.
if ( (0 / zero) == Double::NaN )
{
   Console::WriteLine( "0 / 0 can be tested with Double::NaN." );
}
else
{
   Console::WriteLine( "0 / 0 cannot be tested with Double::NaN; use Double::IsNan() instead." );
}

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