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Categories / Delphi / Constants

 

Nan - not a real number

const NaN = 0.0 / 0.0; Description The NaN constant provides a standard undetrmined number value for assigning to floating point variables. It allows the floating point number to be treated as unassigned. Related commands Infinity Floating point value of infinite size IsInfinite Checks whether a floating point number is infinite IsNaN Checks to see if a floating point number holds a real number Example code : Assign NAN to a number and then test using IsNaN 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; Show full unit code float = NAN float is not a number