# MCS 260 L-21 Mon 1 Mar 2010 : a stack
#
# this program uses a stack_of_data

import stack_of_data
import stack_of_data_io

def pop_or_push(choice):
   "calls pop and push functions"
   if choice == 'a':
      item = input('Give an item : ')
      stack_of_data.push(item)
   elif choice == 'r':
      item = stack_of_data.pop()
      print 'item popped : %d' % item
   else:
      print 'invalid choice, try again'

def test_input_output():
   "test input/output operations"
   K = input('give a list : ')
   stack_of_data_io.input(K)
   L = stack_of_data.length()
   print 'length of stack : %d' % L
   print 'printing top element'
   stack_of_data_io.show_top()
   print 'printing the stack'
   stack_of_data_io.show_all()

while True:
   menu = 'add, remove, or stop? (a/r/s) '
   choice = raw_input(menu)
   if choice == 's': break
   pop_or_push(choice)
   test_input_output()