linked_list1.rb

class LinkedListNode
  attr_accessor :value, :next_node
 
  def initialize(value, next_node=nil)
    @value = value
    @next_node = next_node
  end
  
  def print_values(list_node)
    if list_node
      print "#{list_node.value} --> "
      print_values(list_node.next_node)
    else      
      print "nil\n"
      return
    end
  end
  
  def reverse_list(list)
  # ADD CODE HERE
    my_stack = Stack.new
    

    while list
      # ADD CODE HERE
      my_stack.push(list.value)
      list = list.next_node
    end

    # ADD CODE HERE
    my_stack
  end
end


class Stack
  attr_reader :data
  
  def initialize
    @data = nil
  end

  # Push a value onto the stack
  def push(value)
    @data = LinkedListNode.new(value, @data)
    @data.print_values(@data)
  end

  # Pop an item off the stack.  
  # Remove the last item that was pushed onto the
  # stack and return the value to the user
  def pop
    top_value = @data.value
    @data = @data.next_node
    top_value
  end
end

# stack = Stack.new
# stack.push(1)
# stack.push(2)
# stack.push(3)
# puts stack.pop 
# puts stack.pop 
# puts stack.pop 


node1 = LinkedListNode.new(37)
node2 = LinkedListNode.new(99, node1)
node3 = LinkedListNode.new(12, node2)
 
node3.print_values(node3)

node3.reverse_list(node3)