Creating random numbers with no duplicates

Question

In this case, the MAX is only 5, so I could check the duplicates one by one, but how could I do this in a simpler way? For example, what if the MAX has a value of 20? Thanks

Answer 1

You could use one of the classes implementing the Set interface (API), and then each number you generate, use Set.add() to insert it.

If the return value is false, you know the number has already been generated before.