Double.NaN Pole

Definicja

Reprezentuje wartość, która nie jest liczbą (NaN).Represents a value that is not a number (NaN). To pole jest stałe.This field is constant.

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

Wartość pola

Przykłady

Poniższy przykład ilustruje sposób użycia 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

Uwagi

Metoda lub operator zwraca NaN, gdy wynik operacji jest niezdefiniowany.A method or operator returns NaN when the result of an operation is undefined. Na przykład wynik dzielenia zera przez zero jest NaN, jak pokazano w poniższym przykładzie.For example, the result of dividing zero by zero is NaN, as the following example shows. (Ale należy zauważyć, że dzielenie niezerowej liczby przez zero zwraca wartość PositiveInfinity lub NegativeInfinity, w zależności od znaku dzielnika).(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      

Ponadto wywołanie metody z wartością NaN lub operacją na NaN wartość zwraca NaN, jak pokazano w poniższym przykładzie.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

Użyj metody IsNaN, aby określić, czy wartość nie jest liczbą.Use the IsNaN method to determine whether a value is not a number. Operator Equality traktuje dwa NaN wartości, aby były różne od siebie nawzajem.The Equality operator considers two NaN values to be unequal to one another. Ogólnie rzecz biorąc operatory Double nie mogą być używane do porównywania Double.NaN z innymi wartościami Double, chociaż metody porównania (takie jak Equals i CompareTo) mogą.In general, Double operators cannot be used to compare Double.NaN with other Double values, although comparison methods (such as Equals and CompareTo) can. Poniższy przykład ilustruje różnice w zachowaniu między Double operatory porównania i metody.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

Dotyczy

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