GeneralImplementation.py

# Python program for implementation of stack
 
# import maxsize from sys module 
# Used to return -infinite when stack is empty
from sys import maxsize
 
# Function to create a stack. It initializes size of stack as 0
def createStack():
    stack = []
    return stack
 
# Stack is empty when stack size is 0
def isEmpty(stack):
    return len(stack) == 0
 
# Function to add an item to stack. It increases size by 1
def push(stack, item):
    stack.append(item)
    #print("pushed to stack " + item)
     
# Function to remove an item from stack. It decreases size by 1
def pop(stack):
    if (isEmpty(stack)):
        return str(-maxsize -1) #return minus infinite
     
    return stack.pop()