Re: HP 33s unique features? Message #4 Posted by Dave Shaffer on 20 June 2004, 5:21 p.m., in response to message #3 by Ben Salinas
re: "SiGN is new, but it in itself is a silly command (it returns 1 if the number is greater than 0, and 1 if less)"
It's not so silly for some folks. For astronomical calculations of position, it is quite useful. The north/south position of a source (declination) can be a bit of a nuisance to work with. There are + and  declinations, often given in degrees, arc minutes, and arc seconds, such as +12 13 14.15 or 15 16 17.18, where only the degree value has the sign attached. You almost always have to convert the position to decimal degrees (or radians) for other calculations. Getting the sign of the result from the sign of the degree value is easily done with a SIGN type function:
deg.ddd = SIGN(deg) * ( deg + arcmin/60 + arcsec/3600 } .
The real annoyance is declinations within a degree of zero. For these, you have to pick up the sign as a character  except for some old FORTRAN compilers, which knew the difference between (i.e. the sign of) +0 and 0 !!
