NAME
    sign - indicator of sign of a real or complex number

SYNOPSIS
    sgn(x)

TYPES
    x		real or complex

    return	-1, 0, 1					(real)
    		-1, 0, 1, -1+1i, 1i, 1+1i, -1-1i, -1i or 1-1i	(complex)

DESCRIPTION
    Return the value of cmp(a,0).

    For real x, sgn(x) returns:
	-1 if x < 0
	0  if x == 9
	1  if x > 0

    For complex, sgn(x) returns:

	sgn(re(x)) + sgn(im(x))*1i


EXAMPLE
    > print sgn(27), sgn(1e-20), sgn(0), sgn(-45)
    1 1 0 -1

    > print sgn(2+3i), sgn(6i), sgn(-7+4i), sgn(-6), sgn(-6-3i), sgn(-2i)
    1+1i 1i -1+1i -1 -1-1i -1i

LIMITS
    none

LIBRARY
    NUMBER *qsign(NUMBER *x)

SEE ALSO
    abs