Re^2: Seeing if two numbers have the same sign

[hipowls]

Neat (wish I'd thought of it) but it implicitly assumes that zero is a positive number, given 0 and -1 the test returns 0, given 0 and +1 it returns 1. If the test was ( $x<=0 == $y<=0 ) then zero is treated as both positive and negative and the two previous examples return 1. Which is consistent but might not be what you want.

[graff]

Maybe I'm just old-fashioned (primitive?), but my understanding of the term "same sign", at least as it relates to programming, has always been: when the sign bit of two values is the same, those values have "the same sign". In that interpretation, zero is always included among the set of "non-negative" values: it is the same sign as "1", and not the same sign as "-1".