| Description |
The IsNaN function returns True if the Float parameter is Not a number.
A floating point number can be set to such a value when it is assigned an undetermined value. The standard is :
NAN = 0.0 / 0.0
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| Related commands |
| Infinity |
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Floating point value of infinite size |
| IsInfinite |
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Checks whether a floating point number is infinite |
| NaN |
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Not a real number |
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| Example code : Assign NAN to a number and then test using IsNaN |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
Math, // Unit containing the IsNaN command
SysUtils,
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
float : Double;
begin
// Set the number to an invalid number
float := NAN; // Equivalent to 0.0/0.0
// Although an invalid number, we can still display it
ShowMessage('float = '+FloatToStr(float));
// And we can test to see if it is a valid number
if IsNaN(float)
then ShowMessage('float is not a number')
else ShowMessage('float = '+FloatToStr(float));
end;
end.
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| Hide full unit code |
float = NAN
float is not a number
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