Perhaps need a bit more information there. Is there a range of numbers, i.e. 1-1000, 1-10000, etc. Also how often would you be calling it. The reason I ask is that if you want to be sure you don't call the same number 2 times, you need to record if a number has been called, and if you call it a bunch, you'll start eating memory and computer cycles as you start to hunt for a random number that hasn't been found yet. More info?
