Delete last node of linked list in ruby

Ruby program for Delete last node of linked list. Here problem description and explanation.

#    Ruby program for
#    Delete the last node of singly linked list

#  Linked list node
class LinkNode 
	# Define the accessor and reader of class LinkNode
	attr_reader :data, :next
	attr_accessor :data, :next
	def initialize(data) 
		self.data = data
		self.next = nil
	end

end

class SingleLL 
	# Define the accessor and reader of class SingleLL
	attr_reader :head, :tail
	attr_accessor :head, :tail
	def initialize() 
		self.head = nil
		self.tail = nil
	end

	#  Add new node at the end of linked list
	def addNode(value) 
		#  Create a new node
		node = LinkNode.new(value)
		if (self.head == nil) 
			self.head = node
		else
			self.tail.next = node
		end

		#  Set new last node
		self.tail = node
	end

	#  Display linked list element
	def display() 
		if (self.head == nil) 
			print("Empty Linked List\n")
			return
		end

		temp = self.head
		#  iterating linked list elements
		while (temp != nil) 
			print(temp.data ," → ")
			#  Visit to next node
			temp = temp.next
		end

		print("NULL", "\n")
	end

	#  Delete last node of singly linked list
	def deleteLastNode() 
		if (self.head == nil) 
			print("Empty Linked List\n")
			return
		else
 
			temp = self.head
			find = nil
			#  Find second last node
			while (temp.next != nil) 
				find = temp
				temp = temp.next
			end

			if (find == nil) 
				#  Delete head node of linked list
				self.head = nil
				self.tail = nil
			else
 
				#  Set new last node
				self.tail = find
				find.next = nil
			end

		end

	end

end

def main() 
	sll = SingleLL.new()
	#  Linked list
	#  1 → 2 → 3 → 4 → 5 → 6 → NULL
	sll.addNode(1)
	sll.addNode(2)
	sll.addNode(3)
	sll.addNode(4)
	sll.addNode(5)
	sll.addNode(6)
	print("Before Delete \n")
	sll.display()
	sll.deleteLastNode()
	print("After Delete \n")
	sll.display()
end

main()

Output

Before Delete 
1 → 2 → 3 → 4 → 5 → 6 → NULL
After Delete 
1 → 2 → 3 → 4 → 5 → NULL