signfunction

Syntax   sign ( r : real ) : -1 .. 1

Description   The sign function is used to determine whether a number is positive, zero or negative. It returns 1 if r > 0, 0 if r = 0, and -1 if r < 0. For example, sign (5) is 1 and sign (-23) is -1.

Example   This program reads in numbers and determines if they are positive, zero or negative:

        var x : real
        get x
        case sign ( x ) of
            label 1 : put "Positive"
            label 0 : put "Zero"
            label -1 : put "Negative"
        end case
See also   See also predefined unit Math.