Single.NaN Single.NaN Single.NaN Single.NaN Field

定义

表示非数字 (NaN)。Represents not a number (NaN). 此字段为常数。This field is constant.

public: float NaN = NaN;
public const float NaN = NaN;
val mutable NaN : single
Public Const NaN As Single  = NaN

字段值

示例

下面的示例演示NaN常量。The following example demonstrates the NaN constant.

Single zero = 0;

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

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

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

注解

方法或运算符返回NaN时操作的结果是不确定。A method or operator returns NaN when the result of an operation is undefined. 例如,零被零除的结果是NaN,如下面的示例所示。For example, the result of dividing zero by zero is NaN, as the following example shows. (但请注意,返回一个非零数字除以 0 或者PositiveInfinityNegativeInfinity,取决除数的符号。)(But note that dividing a non-zero number by zero returns either PositiveInfinity or NegativeInfinity, depending on the sign of the divisor.)

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

此外,一种方法调用NaN值或上的一个操作NaN值返回NaN,如下面的示例所示。In addition, a method call with a NaN value or an operation on a NaN value returns NaN, as the following example shows.

float nan1 = Single.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 Single = Single.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

使用IsNaN方法来确定值是否不是一个数字。Use the IsNaN method to determine whether a value is not a number. 一般情况下,Single不能使用运算符来比较Single.NaN与其他Single值,尽管比较方法 (如EqualsCompareTo) 可以。In general, Single operators cannot be used to compare Single.NaN with other Single values, although comparison methods (such as Equals and CompareTo) can. 下面的示例阐释了之间的行为差异Single比较运算符和方法。The following example illustrates the difference in behavior between Single comparison operators and methods.

using System;

public class Example
{
   public static void Main()
   {
      Console.WriteLine("NaN == NaN: {0}", Single.NaN == Single.NaN); 
      Console.WriteLine("NaN != NaN: {0}", Single.NaN != Single.NaN); 
      Console.WriteLine("NaN.Equals(NaN): {0}", Single.NaN.Equals(Single.NaN)); 
      Console.WriteLine("! NaN.Equals(NaN): {0}", ! Single.NaN.Equals(Single.NaN)); 
      Console.WriteLine("IsNaN: {0}", Double.IsNaN(Double.NaN));
      
      Console.WriteLine("\nNaN > NaN: {0}", Single.NaN > Single.NaN); 
      Console.WriteLine("NaN >= NaN: {0}", Single.NaN >= Single.NaN); 
      Console.WriteLine("NaN < NaN: {0}", Single.NaN < Single.NaN);
      Console.WriteLine("NaN < 100.0: {0}", Single.NaN < 100.0f); 
      Console.WriteLine("NaN <= 100.0: {0}", Single.NaN <= 100.0f); 
      Console.WriteLine("NaN >= 100.0: {0}", Single.NaN > 100.0f);
      Console.WriteLine("NaN.CompareTo(NaN): {0}", Single.NaN.CompareTo(Single.NaN)); 
      Console.WriteLine("NaN.CompareTo(100.0): {0}", Single.NaN.CompareTo(100.0f)); 
      Console.WriteLine("(100.0).CompareTo(Single.NaN): {0}", (100.0f).CompareTo(Single.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(Single.NaN): 1
Module Example
   Public Sub Main()
      Console.WriteLine("NaN = NaN: {0}", Single.NaN = Single.NaN) 
      Console.WriteLine("NaN <> NaN: {0}", Single.NaN <> Single.NaN) 
      Console.WriteLine("NaN.Equals(NaN): {0}", Single.NaN.Equals(Single.NaN)) 
      Console.WriteLine("Not NaN.Equals(NaN): {0}", Not Single.NaN.Equals(Single.NaN)) 
      Console.WriteLine("IsNaN: {0}", Double.IsNaN(Double.NaN))
      Console.WriteLine()
      Console.WriteLine("NaN > NaN: {0}", Single.NaN > 100.0f) 
      Console.WriteLine("NaN >= NaN: {0}", Single.NaN >= 100.0f) 
      Console.WriteLine("NaN < NaN: {0}", Single.NaN < Single.NaN)
      Console.WriteLine("NaN < 100.0: {0}", Single.NaN < 100.0f) 
      Console.WriteLine("NaN <= 100.0: {0}", Single.NaN <= 100.0f) 
      Console.WriteLine("NaN >= 100.0: {0}", Single.NaN > 100.0f)
      Console.WriteLine("NaN.CompareTo(NaN): {0}", Single.NaN.CompareTo(Single.Nan)) 
      Console.WriteLine("NaN.CompareTo(100.0): {0}", Single.NaN.CompareTo(100.0f)) 
      Console.WriteLine("(100.0).CompareTo(Single.NaN): {0}", (100.0f).CompareTo(Single.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(Single.NaN): 1

适用于

另请参阅