Delphi Basics : NaN command

DelphiBasics

NaN
Constant

Not a real number

Math unit

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

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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