Produced Numbers are must different each other with arc4random

Question

i want to use arc4random but produced Numbers are must different each other.

How do i do this example?

Answer 1

How about this:

let desired = 20
var randomSet: Set<Int> = [] //Sets guarantee uniqueness
var array: [Int] = [] //Use arrays to guarantee the order

while array.count < desired {
    let random = Int(arc4random())
    if !randomSet.contains(random) {
        array.append(random)
        randomSet.insert(random)
    }
}

Or, using LeoDaubus' suggestion:

while array.count < desired {
    let random = Int(arc4random())
    if randomSet.insert(random).inserted {
        array.append(random)
    }
}