Single.NaN Field

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.

float zero = 0.0f;
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.

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

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.

float result = Single.NaN;
Console.WriteLine("{0} = Single.NaN: {1}", 
                  result, result == Single.NaN);
// The example displays the following output: 
//         NaN = Single.Nan: False

The following code 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.");
}

.NET Framework

.NET Framework Client Profile

Portable Class Library

.NET for Windows Store apps

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference