[lelf]

1/(0-0) = -∞, 1/(0+0) = ∞

[stephencanon]

Actually, (0-0) evaluates to +0 in the default rounding mode, so both of those expressions will typically return +∞.

1/-0 will give you -∞, of course.

[lelf]

Well, I meant it as in math notation, not in C.

(Strictly speaking, 1/0 in C is kaboom! (undefined behaviour))