Need for predictable random generator

Question

I\'m a web-game developer and I got a problem with random numbers. Let\'s say that a player has 20% chance to get a critical hit with his sword. That means, 1 out of 5 hits

Answer 1

I would propose the following "randomly delayed putback die":

• Maintain two arrays, one (in-array) initially filled with the values from 0 to n-1, the other (out-array) empty
• When a result is requested:
  • return a random value from all defined values in in-array
  • move this value from in-array to out-array
  • move one random (over all elements, including the undefined!) element from out-array back into in-array

This has the property that it will "react" more slowly the bigger n is. For example, if you want a 20% chance, setting n to 5 and hitting on a 0 is "less random" than setting n to 10 and hitting on a 0 or 1, and making it 0 to 199 out of 1000 will be almost indistinguishable from true randomness over a small sample. You will have to adjust n to your sample size.