Updated: March 2012
Represents not a number (NaN). This field is constant.
Assembly: mscorlib (in mscorlib.dll)
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.
Dim zero As Double = 0
Console.WriteLine("{0} / {1} = {2}", zero, zero, zero/zero)
' The example displays the following output:
' 0 / 0 = NaN
double zero = 0.0;
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.
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
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
Use the IsNaN method to determine whether a value is not a number. Two NaN values are considered unequal to one another. Therefore, it is not possible to determine whether a value is not a number by using the equality operator to compare it to another value that is equal to NaN. The comparison returns false, as the following example shows.
Dim result As Double = Double.Nan
Console.WriteLine("{0} = Double.Nan: {1}",
result, result = Double.Nan)
' The example displays the following output:
' NaN = Double.Nan: False
double result = Double.NaN;
Console.WriteLine("{0} = Double.Nan: {1}",
result, result == Double.NaN);
// The example displays the following output:
// NaN = Double.Nan: False
The following code example demonstrates the NaN constant.
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
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." );
}
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.