Binary Tree: Traversal

Question | May 9, 2016 | rparekh 

Below is a binary tree with elements:

enter image description here

The tree, 'Tree' and its node 'Node' are represented as:

struct Node {
    std::string key;
    Node* left;
    Node* right;
    Node(std::string& k)
       :key(k),left(NULL),right(NULL) {}
};

struct Tree {
    Tree():root(NULL){}
    void traversal(Node* n);
    // .... more methods......
    Node* root;
};

Below is the implementation of the traversal function:

void Tree::traversal(Node* n) 
{
       queue<Node*> q;
       q.push(n);

       while (! q.empty())
       {
          Node* v = q.front();
          std::cout << v->key << " - ";

          if (v->left != NULL)
                q.push(v->left);

           if (v->right != NULL)
                q.push(v->right);

           q.pop();
       }
    }

What is the output of this code?

2015 nextptr