Sieve of Eratosthenes

Sieve of Eratosthenes

// Sieve of Eratosthenes
let numbers : Array<Int> = [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]


func sieve(array: [Int], startIndex: Int) -> [Int] {
    
    let filteredArray = array.filter{(x) -> Bool in
        if  x == array[startIndex] {
            return true
        } else {
            return x % array[startIndex] != 0
        }
    }
    
    if  array == filteredArray  {
        return filteredArray
    } else {
        return sieve(filteredArray,startIndex + 1)
    }
    
}


var primes : [Int] = sieve(numbers,numbers.startIndex)