The functions associated with stack are:

empty() – Returns whether the stack is empty – Time Complexity : O(1) size() – Returns the size of the stack – Time Complexity : O(1) top() – Returns a reference to the top most element of the stack – Time Complexity : O(1) push(g) – Adds the element ‘g’ at the top of the stack – Time Complexity : O(1) pop() – Deletes the top most element of the stack – Time Complexity : O(1) '''

'''Implementation using list:''' print('----------Implementation using list-------------') stack = []

stack.append('January') stack.append('February') stack.append('March') stack.append('April')

print(stack)

print(stack.pop()) print(stack)

print(stack.pop()) print(stack)

print(stack.pop()) print(stack)

print(stack.pop()) print(stack)

'''Implementation using collections.deque''' print('----------Implementation using collections.deque-------------') from collections import deque

stack_de = deque()

stack_de.append('Book') stack_de.append('pen') stack_de.append('College') stack_de.append('University')

print(stack_de)

print(stack_de.pop()) print(stack_de)

print(stack_de.pop()) print(stack_de)

print(stack_de.pop()) print(stack_de)

print(stack_de.pop()) print(stack_de)

'''Exaple Of Stack Implementation''' print('-------------Exaple Of Stack Implementation---------------')

class Stack(): def init(self): self.items = []

def push(self,item): self.items.append(item) def pop(self): return self.items.pop() def is_emppty(self): return self.items == [] def peek(self): if not self.is_emppty(): return self.items[-1] def get_stack(self): return self.items

myStack = Stack() myStack.push('Java') myStack.push('Python') myStack.push('Dart') myStack.push('JavaScript')

print(myStack)

print('----test----') print(myStack.peek()) print(myStack.is_emppty()) print(myStack.get_stack())

Stack Program By Python