btree.rb

class Node
  attr_accessor :data, :left, :right

  def initialize(data = nil)
    @data  = data
    @left  = nil
    @right = nil
  end
end

class TreeManager
  def insert(root, data)
    if root.nil?
      root = Node.new
      root.data = data
    elsif data < root.data
      root.left = insert(root.left, data)
    else
      root.right = insert(root.right, data)
    end

    root
  end
end

@tree_manager = TreeManager.new

@root = nil

(Array.new(100) { rand(1..100) }).each do |number|
  @root = @tree_manager.insert @root, number
end

p @root