Double.NaN Field
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Represents a value that is not a number (NaN
). This field is constant.
public: double NaN = NaN;
public const double NaN = NaN;
val mutable NaN : double
Public Const NaN As Double = NaN
Value = 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.");
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
A method or operator returns NaN when the result of an operation is undefined. For example, the result of dividing zero by zero is NaN, as the following example shows. (However, 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
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
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
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
Use the IsNaN method to determine whether a value is not a number. The Equality operator considers two NaN values to be unequal to one another. In general, Double operators cannot be used to compare Double.NaN with other Double values, although comparison methods (such as Equals and CompareTo) can. 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
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
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
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