stackNode.py

'''class StackNode:
    def __init__(self, data):
        self.data = data
        self.next = None

class Stack:
    def __init__(self):
        self.root = None

    def isEmpty(self):
        return True if self.root is None else False

    def push(self, data):
        newNode = StackNode(data)
        newNode.next = self.root
        self.root = newNode
        print ('% d pushed to stack ') % (data)

    def pop(self):
        if(self.isEmpty()):
            return float('-inf')
        temp = self.root
        self.root = self.root.next
        popped = temp.data
        return popped

    def peek(self):
        if self.isEmpty():
            return float('-inf')
        return self.root.data

    #driver class
    stack = Stack()
    stack.push(10)
    stack.push(20)
    stack.push(30)
 
    print ("% d popped from stack" % (stack.pop()))
    print ("Top element is % d " % (stack.peek()))
    '''
        # Python program for linked list implementation of stack

# Class to represent a node


class StackNode:

	# Constructor to initialize a node
	def __init__(self, data):
		self.data = data
		self.next = None


class Stack:

	# Constructor to initialize the root of linked list
	def __init__(self):
		self.root = None

	def isEmpty(self):
		return True if self.root is None else False

	def push(self, data):
		newNode = StackNode(data)
		newNode.next = self.root
		self.root = newNode
		print("% d pushed to stack" % (data))

	def pop(self):
		if (self.isEmpty()):
			return float("-inf")
		temp = self.root
		self.root = self.root.next
		popped = temp.data
		return popped

	def peek(self):
		if self.isEmpty():
			return float("-inf")
		return self.root.data


# Driver code
stack = Stack()
stack.push(10)
stack.push(20)
stack.push(30)

print("% d popped from stack" % (stack.pop()))
print("Top element is % d " % (stack.peek()))

# This code is contributed by Nikhil Kumar Singh(nickzuck_007)