title: Level-order traversal of a binary tree
body: <p>I want to perform level-order traversal of a binary tree. Hence, for a given tree, say:</p>
  
  <pre><code>     3
      / \
     2   1
    / \   \
   4   6   10
  </code></pre>
  
  <p>the output would be:</p>
  
  <pre><code>3 2 1 4 6 10
  </code></pre>
  
  <p>I understand that I could use some sort of queue, but what is the algorithm to do this in C recursively? Any help appreciated.</p>