Print out a tree of nodes with multiple children each.

NodeTraversal.swift

//
//  main.swift
//  NodeTraversal
//
//  Created by Steven Hepting on 11/16/15.
//  Copyright © 2015 Steven Hepting. All rights reserved.
//  Algorithm from http://bit.ly/1kSdSvc
//

import Foundation

class Node {
    var value: String = ""
    var children: [Node]?
    
    init(_ value: String, children: [Node]? = nil) {
        self.value = value
        self.children = children
    }
    
    func printNode() {
        printNode(prefix: "", isLast: true)
    }
    
    func printNode(prefix prefix: String = "", isLast: Bool) {
        let indicator = isLast ? "└──" : "├──"
        print("\(prefix)\(indicator) \(value)")
        guard let children = children else { return }
        
        for (index, child) in children.enumerate() {
            let isLastChild = index == (children.count - 1)
            let childIndicator = isLast ? "    " : "│   "
            child.printNode(prefix: "\(prefix)\(childIndicator)", isLast: isLastChild)
        }
    }
}

print("Hello, World!")

let a = Node("a")
let b = Node("b")
let c = Node("c", children: [a, b])
let d = Node("d")
let asdf = Node("asdf")
let e = Node("e", children: [asdf])
let f = Node("f")
let z = Node("z", children: [c, d, e, f])

z.printNode()