#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <deque>

using namespace std;

class node
{ protected:
    string data;
    vector <node *> child;

  public:
    node(string d)
    { data = d; }

    node * add(node * p)
    { child.push_back(p);
      return this; }

    string get_data()
    { return data; }

    int get_num_children()
    { return child.size(); }

    node * get_child(int i)
    { return child[i]; }
};

node * mn(string s)   // mn calls constructor, but is shorter to type
{ return new node(s); }

void print(node * p, int depth = 0)
{ cout << setw(depth * 5) << "" << p->get_data() << "\n";
  int num = p->get_num_children();
  int i = 0;
  while (i < num)
  { print(p->get_child(i), depth + 1);
    i += 1; } }

void bf_print(node * here)
{ deque <node *> queue;
  queue.push_back(here);
  while (! queue.empty())
  { here = queue.front();
    queue.pop_front();
    cout << here->get_data() << "\n";
    int num = here->get_num_children();
    for (int i = 0; i < num; i += 1)
      queue.push_back(here->get_child(i)); } }

int main()
{ node * t = mn("ant")
                      ->add(mn("bat")
                                     ->add(mn("egg")
                                                    ->add(mn("kit"))
                                                    ->add(mn("log")))
                                     ->add(mn("fig"))
                                     ->add(mn("git")
                                                    ->add(mn("map"))
                                                    ->add(mn("nut"))
                                                    ->add(mn("old"))
                                                    ->add(mn("pig"))))
                      ->add(mn("cat")
                                     ->add(mn("hat")))
                      ->add(mn("dog")
                                     ->add(mn("ink")
                                                    ->add(mn("qat"))
                                                    ->add(mn("rat")))
                                     ->add(mn("jug")
                                                    ->add(mn("sud"))
                                                    ->add(mn("tip"))));
  bf_print(t); }