Double.IsNaN(Double) Method

Definition

Returns a value that indicates whether the specified value is not a number (NaN).

public:
 static bool IsNaN(double d);
public static bool IsNaN (double d);
static member IsNaN : double -> bool
Public Shared Function IsNaN (d As Double) As Boolean

Parameters

d
Double

A double-precision floating-point number.

Returns

true if d evaluates to NaN; otherwise, false.

Examples

The following code example illustrates the use of IsNaN:

// This will return true.
if ( Double::IsNaN( 0 / zero ) )
{
   Console::WriteLine( "Double::IsNan() can determine whether a value is not-a-number." );
}
// This will return true.
if (Double.IsNaN(0 / zero)) 
   Console.WriteLine("Double.IsNan() can determine whether a value is not-a-number.");
' This will return true.
If Double.IsNaN(0 / zero) Then
    Console.WriteLine("Double.IsNan() can determine whether a value is not-a-number.")
End If

Remarks

Floating-point operations return NaN to signal that result of the operation is undefined. For example, dividing 0.0 by 0.0 results in NaN.

Note

IsNaN returns false if a Double value is either PositiveInfinity or NegativeInfinity. To test for these values, use the IsInfinity, IsPositiveInfinity, and IsNegativeInfinity methods.

Applies to

See also