The title already contains my question. Here's the same thing in other form, just in case the title isn't clear: Is it possible that the following function returns 1, or is it always 0? Code (Text): x = rand(); y = rand(); return (x == y); There's two possibilities. Either the probability for 1 is precisely zero, or then the probability 1 is something very small but non-zero. I'm programming with c, and this is a rand-function that requires stdlib.h to be included.