# Double.NaN Champ

## Définition

Représente une valeur qui n'est pas un nombre (`NaN`).Represents a value that is not a number (`NaN`). Ce champ est constant.This field is constant.

``public: double NaN = NaN;``
``public const double NaN = NaN;``
``val mutable NaN : double``
``Public Const NaN As Double  = NaN``

## Exemples

L'exemple suivant illustre l'utilisation de NaN :The following example illustrates the use of NaN:

``````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." );
}
``````
``````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.");
``````
``````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
``````

## Remarques

Une méthode ou un opérateur retourne NaN lorsque le résultat d’une opération n’est pas défini.A method or operator returns NaN when the result of an operation is undefined. Par exemple, le résultat de la Division de zéro par zéro est NaN, comme le montre l’exemple suivant.For example, the result of dividing zero by zero is NaN, as the following example shows. (Notez toutefois que la Division d’un nombre différent de zéro retourne la valeur PositiveInfinity ou NegativeInfinity, selon le signe du diviseur).(But note that dividing a non-zero number by zero returns either PositiveInfinity or NegativeInfinity, depending on the sign of the divisor.)

``````double zero = 0.0;
Console.WriteLine("{0} / {1} = {2}", zero, zero, zero/zero);
// The example displays the following output:
//         0 / 0 = NaN
``````
``````Dim zero As Double = 0
Console.WriteLine("{0} / {1} = {2}", zero, zero, zero/zero)
' The example displays the following output:
'         0 / 0 = NaN
``````

En outre, un appel de méthode avec une valeur NaN ou une opération sur une valeur NaN retourne NaN, comme le montre l’exemple suivant.In addition, a method call with a NaN value or an operation on a NaN value returns NaN, as the following example shows.

``````double nan1 = Double.NaN;

Console.WriteLine("{0} + {1} = {2}", 3, nan1, 3 + nan1);
Console.WriteLine("Abs({0}) = {1}", nan1, Math.Abs(nan1));
// The example displays the following output:
//       3 + NaN = NaN
//       Abs(NaN) = NaN
``````
``````Dim nan1 As Double = Double.NaN

Console.WriteLine("{0} + {1} = {2}", 3, nan1, 3 + nan1)
Console.WriteLine("Abs({0}) = {1}", nan1, Math.Abs(nan1))
' The example displays the following output:
'       3 + NaN = NaN
'       Abs(NaN) = NaN
``````

Utilisez la méthode IsNaN pour déterminer si une valeur n’est pas un nombre.Use the IsNaN method to determine whether a value is not a number. L’opérateur Equality considère que deux valeurs NaN sont inégales les unes des autres.The Equality operator considers two NaN values to be unequal to one another. En général, les opérateurs de Double ne peuvent pas être utilisés pour comparer des Double.NaN avec d’autres valeurs de Double, bien que les méthodes de comparaison (telles que Equals et CompareTo) puissent.In general, Double operators cannot be used to compare Double.NaN with other Double values, although comparison methods (such as Equals and CompareTo) can. L’exemple suivant illustre la différence de comportement entre Double opérateurs de comparaison et les méthodes.The following example illustrates the difference in behavior between Double comparison operators and methods.

``````using System;

public class Example
{
public static void Main()
{
Console.WriteLine("NaN == NaN: {0}", Double.NaN == Double.NaN);
Console.WriteLine("NaN != NaN: {0}", Double.NaN != Double.NaN);
Console.WriteLine("NaN.Equals(NaN): {0}", Double.NaN.Equals(Double.NaN));
Console.WriteLine("! NaN.Equals(NaN): {0}", ! Double.NaN.Equals(Double.NaN));
Console.WriteLine("IsNaN: {0}", Double.IsNaN(Double.NaN));

Console.WriteLine("\nNaN > NaN: {0}", Double.NaN > Double.NaN);
Console.WriteLine("NaN >= NaN: {0}", Double.NaN >= Double.NaN);
Console.WriteLine("NaN < NaN: {0}", Double.NaN < Double.NaN);
Console.WriteLine("NaN < 100.0: {0}", Double.NaN < 100.0);
Console.WriteLine("NaN <= 100.0: {0}", Double.NaN <= 100.0);
Console.WriteLine("NaN >= 100.0: {0}", Double.NaN > 100.0);
Console.WriteLine("NaN.CompareTo(NaN): {0}", Double.NaN.CompareTo(Double.NaN));
Console.WriteLine("NaN.CompareTo(100.0): {0}", Double.NaN.CompareTo(100.0));
Console.WriteLine("(100.0).CompareTo(Double.NaN): {0}", (100.0).CompareTo(Double.NaN));
}
}
// The example displays the following output:
//       NaN == NaN: False
//       NaN != NaN: True
//       NaN.Equals(NaN): True
//       ! NaN.Equals(NaN): False
//       IsNaN: True
//
//       NaN > NaN: False
//       NaN >= NaN: False
//       NaN < NaN: False
//       NaN < 100.0: False
//       NaN <= 100.0: False
//       NaN >= 100.0: False
//       NaN.CompareTo(NaN): 0
//       NaN.CompareTo(100.0): -1
//       (100.0).CompareTo(Double.NaN): 1
``````
``````Module Example
Public Sub Main()
Console.WriteLine("NaN = NaN: {0}", Double.NaN = Double.NaN)
Console.WriteLine("NaN <> NaN: {0}", Double.NaN <> Double.NaN)
Console.WriteLine("NaN.Equals(NaN): {0}", Double.NaN.Equals(Double.NaN))
Console.WriteLine("Not NaN.Equals(NaN): {0}", Not Double.NaN.Equals(Double.NaN))
Console.WriteLine("IsNaN: {0}", Double.IsNaN(Double.NaN))
Console.WriteLine()
Console.WriteLine("NaN > NaN: {0}", Double.NaN > 100.0)
Console.WriteLine("NaN >= NaN: {0}", Double.NaN >= 100.0)
Console.WriteLine("NaN < NaN: {0}", Double.NaN < Double.NaN)
Console.WriteLine("NaN < 100.0: {0}", Double.NaN < 100.0)
Console.WriteLine("NaN <= 100.0: {0}", Double.NaN <= 100.0)
Console.WriteLine("NaN >= 100.0: {0}", Double.NaN > 100.0)
Console.WriteLine("NaN.CompareTo(NaN): {0}", Double.NaN.CompareTo(Double.Nan))
Console.WriteLine("NaN.CompareTo(100.0): {0}", Double.NaN.CompareTo(100.0))
Console.WriteLine("(100.0).CompareTo(Double.NaN): {0}", (100.0).CompareTo(Double.NaN))
End Sub
End Module
' The example displays the following output:
'       NaN == NaN: False
'       NaN != NaN: True
'       NaN.Equals(NaN): True
'       ! NaN.Equals(NaN): False
'       IsNaN: True
'
'       NaN > NaN: False
'       NaN >= NaN: False
'       NaN < NaN: False
'       NaN < 100.0: False
'       NaN <= 100.0: False
'       NaN >= 100.0: False
'       NaN.CompareTo(NaN): 0
'       NaN.CompareTo(100.0): -1
'       (100.0).CompareTo(Double.NaN): 1
``````