[NumLock]

как-то так:

Indicates whether a numeric value is positive, negative, or zero.

Unit

Math

Category

Arithmetic routines

Delphi syntax:

type TValueSign = -1..1;
function Sign(const AValue: Double): TValueSign; overload;
function Sign(const AValue: Integer): TValueSign; overload;
function Sign(const AValue: Int64): TValueSign; overload;

Description

Use Sign to test the sign of a numeric value. Sign returns

0 if AValue is zero.
1 if AValue is greater than zero.
-1 if AValue is less than zero.