A quick and dirty reversed linked list implementation in swift 4.

ReverseLinkedList.swift

// Reverse Linked List
class Node {
    let value: Int
    var next: Node?
    
    init(value: Int, next: Node?) {
        self.value = value
        self.next = next
    }
}
let threeNode = Node(value: 3, next: nil)
let twoNode = Node(value: 2, next: threeNode)
let oneNode = Node(value: 1, next: twoNode)

func printList(head: Node?) {
    print("Printing out list of nodes")
    var currentNode = head
    
    while currentNode != nil {
        print(currentNode?.value ?? -1)
        currentNode = currentNode?.next
    }
}

func reverseList(head: Node?) -> Node? {
    var currentNode = head
    var previous: Node?
    var next: Node?
    
    while currentNode != nil {
        next = currentNode?.next
        currentNode?.next = previous
        previous = currentNode
        currentNode = next
    }
    return previous
}
let reversedList = reverseList(head: oneNode)
printList(head: reversedList)