Add #depth method

Author: Grayvox

lib/tree.rb

@@ -111,6 +111,15 @@ def height(value, node = find(value))
     [left_height, right_height].max + 1
   end
 
+  def depth(value, current_node = @root, result = 0)
+    return nil if find(value).nil?
+    return result if value == current_node.data
+
+    return depth(value, current_node.left, result + 1) if value < current_node.data
+
+    depth(value, current_node.right, result + 1) if value > current_node.data
+  end
+
   def balanced?
     simulated_rebalance = rebalance(change_root: false)
     return true if simulated_rebalance == @root

main.rb

@@ -26,9 +26,9 @@
 puts '--- #postorder ---'
 p tree.postorder # returns all nodes in postorder
 puts '--- #height ---'
-p tree.height(5) # returns 3, the amount of nodes away it is from the lowest leaf
+p tree.height(5) # returns 3, the amount of nodes it is from the lowest leaf ("height")
 puts '--- #depth ---'
-
+p tree.depth(7) # returns 3, the amount of nodes it is from the root node ("depth")
 puts '--- #balanced? ---'
 p tree.balanced? # returns true
 puts '--- #rebalance ---'