Fibonachi

fibonachi.swift

func fibonachi (n: Int) -> Int {
    guard n > 1 else {
        return 1
    }
    var prev = 0
    var cur = 1
    for _ in 1..<n {
        (prev, cur) = (cur, prev + cur)
    }
    
    return cur;
}

fibonachi(n: 6) //return 8