Double.NaN フィールド

定義

非数 (NaN) の値を表します。 このフィールドは定数です。

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

フィールド値

Double

NaN の使用例を次に示します。

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.");
let zero = 0.

// This condition will return false.
if 0. / zero = Double.NaN then
    printfn "0 / 0 can be tested with Double.NaN."
else
    printfn "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

注釈

操作の結果が未定義の場合、メソッドまたは演算子が返します NaN 。 たとえば、次の例に示すように、0 を 0 で除算した結果は NaN、次のようになります。 (ただし、0 以外の数値を 0 で除算すると、除数の符号に応じて、どちらか PositiveInfinityNegativeInfinity返されることに注意してください)。

double zero = 0.0;
Console.WriteLine("{0} / {1} = {2}", zero, zero, zero/zero);
// The example displays the following output:
//         0 / 0 = NaN
let zero = 0.0
printfn $"{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

さらに、次の例に示すように、値または値に対する操作を含むNaNメソッド呼び出しNaNが返NaNされます。

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
let nan1 = Double.NaN

printfn $"{3} + {nan1} = {3. + nan1}"
printfn $"abs({nan1}) = {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

このメソッドを IsNaN 使用して、値が数値でないかどうかを判断します。 演算子は Equality 、2 つの NaN 値が互いに等しくないと見なします。 一般に、Double演算子を使用して他Doubleの値と比較Double.NaNすることはできませんが、比較メソッド (などEqualsCompareTo) は可能です。 次の例は、比較演算子とメソッドの動作 Double の違いを示しています。

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
open System

printfn $"NaN = NaN: {Double.NaN = Double.NaN}"
printfn $"NaN <> NaN: {Double.NaN <> Double.NaN}"
printfn $"NaN.Equals(NaN): {Double.NaN.Equals Double.NaN}"
printfn $"not (NaN.Equals NaN): {not (Double.NaN.Equals Double.NaN)}"
printfn $"IsNaN: {Double.IsNaN Double.NaN}"

printfn $"\nNaN > NaN: {Double.NaN > Double.NaN}"
printfn $"NaN >= NaN: {Double.NaN >= Double.NaN}"
printfn $"NaN < NaN: {Double.NaN < Double.NaN}"
printfn $"NaN < 100.0: {Double.NaN < 100.0}"
printfn $"NaN <= 100.0: {Double.NaN <= 100.0}"
printfn $"NaN >= 100.0: {Double.NaN > 100.0}"
printfn $"NaN.CompareTo(NaN): {Double.NaN.CompareTo Double.NaN}"
printfn $"NaN.CompareTo(100.0): {Double.NaN.CompareTo 100.0}"
printfn $"(100.0).CompareTo(Double.NaN): {(100.0).CompareTo Double.NaN}"
// The example displays the following output:
//       NaN = NaN: False
//       NaN <> NaN: True
//       NaN.Equals(NaN): True
//       not (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

適用対象

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