class Node:
def __init__(self, value):
self.value = value
self.next = None
class Stack:
def __init__(self):
self.top = None
self.bottom = None
self.length = 0
def peek(self):
return self.printTop()
def push(self, value):
newNode = Node(value)
if self.length == 0:
self.top = newNode
self.bottom = newNode
else:
newNode.next = self.top
self.top = newNode
self.length += 1
return self.printStack()
def pop(self):
'''if self.length == 0:
self.top = None
self.bottom = None
self.length = 0'''
if not self.top:
return None
if self.top == self.bottom:
self.bottom = None
self.top = self.top.next
self.length -= 1
return self.printStack()
def printTop(self):
print(self.top.value)
def printStack(self):
currentNode = self.top
#values = []
while currentNode:
#values.append(currentNode.value)
print(currentNode.value, end=' -> ')
currentNode = currentNode.next
#print(values)
print()
#isEmpty
myStack = Stack()
#Discord
#Udemy
#google
myStack.push("Discord")
myStack.push("Udemy")
myStack.push("google")
#myStack.pop()
myStack.peek()
class Node:
def __init__(self, value):
self.value = value
self.next = None
class Stack:
def __init__(self):
self.items = []
def peek(self):
return self.printTop()
def push(self, value):
newNode = Node(value)
self.items.append(newNode)
self.top = self.items[-1]
self.bottom = self.items[0]
return self.printStack()
def pop(self):
if len(self.items) == 0:
return None
self.items.pop()
if len(self.items) != 0:
self.top = self.items[-1]
self.bottom = self.items[0]
return self.printStack()
def printTop(self):
print(self.top.value)
def printStack(self):
for item in self.items:
print(item.value, end=' -> ')
print()
#isEmpty
myStack = Stack()
#Discord
#Udemy
#google
myStack.push("Discord")
myStack.push("Udemy")
myStack.push("google")
#myStack.pop()
myStack.peek()
myStack.pop()
myStack.peek()
myStack.printStack()
