Print linked node

class Node{
    var next : Node?
    var val : Int
    init(_ val : Int) {
        self.val = val
    }
}

func printNode(_ root: Node?) {
    guard let root = root else {
        return
    }
    printNode(root.next)
    print(root.val)
}



print()

let n1 = Node(1)
let n2 = Node(2)
let n3 = Node(3)
let n4 = Node(4)

n1.next = n2
n2.next = n3
n3.next = n4