did part of it

tree-practice.rb

@@ -9,13 +9,201 @@ def initialize(val)
 end
 
 def print_infix(node)
+  # puts "#{node.value}"
   return if node == nil
   print_infix(node.left)
   print node.value + " "
   print_infix(node.right)
 end
 
+
+# 1. Let's write a method that prints out all the operators that exist in the tree. _Added Fun: If there are duplicate operators, don't print them separately, but instead print a tally of all operators found._
+
+# recursively go down the tree starting from the root (left then right)
+# return if the node is equal to nil
+# if node value is nil, print it out.
+
+def operators(node)
+  return if node == nil
+  operators(node.left)
+  if node.left != nil || node.right != nil
+    unless node.value.to_i.to_s == node.value
+      print node.value + " "
+    end
+  end
+  operators(node.right)
+end
+
+
+# 2. Write a method that returns the count of non-operators (in this case, leaves) in the tree. _Added Fun: print the level of the tree that each leaf appears on._
+
+# this would be similar to the operator method
+# recursively loop through the left then right
+# if the node.value is not nil (= numeric) then +1 to the counter
+# break case = 0
+#
+# def leafs(node, result)
+#   return 0 if node == nil
+#   if node.value.to_i.to_s == node.value
+#     result = leafs(node.left, ) + leafs(node.right)
+#
+#   # end
+# end
+#
+# def leafs(node)
+#   leaf_helper(node.left) + leaf_helper(node.right)
+# end
+
+def leafs(node)
+  return if node == nil
+  leafs(node.left)
+  if node.value.to_i.to_s == node.value
+    print node.value+" "
+  end
+  leafs(node.right)
+end
+
+# 2. `3 + 2 - 10`
+#     -
+#   +  10
+# 3  2
+
+# 3. Write methods to print the tree in prefix and postfix notations.
+# For prefix
+# keep going down the left side of the (left) tree
+# print out the nodes in order
+# when it hits nil, go down the right side of the left tree
+# when left-right hits nil, go down the right side of the tree
+# repeat same left right sequence on the right side
+
+def prefix(node)
+  return if node == nil
+  print node.value + " "
+  prefix(node.left)
+  prefix(node.right)
+end
+
+# For postfix
+# Go down the left tree, all the way down the left
+ # at the end, print out that node.
+ # go down the right part, at the end print it
+ # then proceed to print out the rest of the left.
+ # again with the right??
+
+
+def postfix(node)
+  return if node == nil
+  postfix(node.left)
+  postfix(node.right)
+  print node.value + " "
+end
+
+
+
+# 4. Write a method that returns whether or not a given operator exists in the tree. _Added fun: If the operator occurs more than once, return the count on how many times it occurs - you may return 0 if it doesn't exist in the tree._
+
+# It would follow the operator method (but pop off an operator array)
+# would check against an array of operators to see if it exists.
+
+# 5. _Added Fun: Evaluate an infix binary tree._
+
+
+# ## TDD
+# 1. Come up with at least 3 test cases for problems 1-4 above. _Added Fun: #5 too._
+# one for if there isn't a right part of the tree
+# one with multiple operators in a row
+# one with
+
+
+
+
+# 1. `3 + 2`
+  #   +
+  # 3  2
 root = TreeNode.new("+")
 root.left = TreeNode.new("3")
 root.right = TreeNode.new("2")
-print_infix(root)
+puts "infix"
+puts print_infix(root) # 3 + 2
+puts "prefix"
+puts prefix(root) # + 3 2
+puts "postfix"
+puts postfix(root) # 3 2 +
+puts "operators"
+puts operators(root)
+puts "leafs"
+puts leafs(root)
+puts
+
+
+# 2. `3 + 2 - 10`
+#     -
+#   +  10
+# 3  2
+root = TreeNode.new("-")
+root.left = TreeNode.new("+")
+root.left.left = TreeNode.new("3")
+root.left.right = TreeNode.new("2")
+root.right = TreeNode.new("10")
+puts "infix"
+puts print_infix(root) # 3 + 2 - 10
+puts "prefix"
+puts prefix(root) # - + 3 2 10
+puts "postfix"
+puts postfix(root) # 3 2 + 10 -
+puts "operators"
+puts operators(root)
+puts "leafs"
+puts leafs(root)
+puts
+
+
+# 3. `(4 * 3) + 2`
+  #     +
+  #   *   2
+  # 4   3
+root = TreeNode.new("+")
+root.left = TreeNode.new("*")
+root.left.left = TreeNode.new("4")
+root.left.right = TreeNode.new("3")
+root.right = TreeNode.new("2")
+puts "infix"
+puts print_infix(root) # 4 * 3 + 2
+puts "prefix"
+puts prefix(root) # + * 4 3 2
+puts "postfix"
+puts postfix(root) # 4 3 * 2 +
+puts "operators"
+puts operators(root)
+puts "leafs"
+puts leafs(root)
+puts
+
+# # 4. `( (4 * 3 )+ 2 )- (10 % 5)`
+#         -
+#       2  %
+#     +   5  10
+#   *
+# 4  3
+
+
+root = TreeNode.new("-")
+root.left = TreeNode.new("2")
+root.left.left = TreeNode.new("+")
+root.left.left.left = TreeNode.new("*")
+root.left.left.left.left = TreeNode.new("4")
+root.left.left.left.right = TreeNode.new("3")
+root.right = TreeNode.new("%")
+root.right.right = TreeNode.new("10")
+root.right.left = TreeNode.new("5")
+puts "infix"
+puts print_infix(root) # 4 * 3 + 2 - 10 % 5
+puts "prefix"
+puts prefix(root) # - 2 + * 4 3 % 5 10
+puts "postfix"
+puts postfix(root) # 4 3 * + 2 5 10 % -
+puts "operators"
+puts operators(root)
+puts "leafs"
+puts leafs(root)
+puts