'''
    CS5001
    Fall 2018
    Sample code -- using a stack to reverse a string
'''

from mystax import Stack

def rev_string(string):
    ''' Function rev_string
        Input: string (a string!)
        Returns: the same string, but in backwards order
    '''
    stack = Stack()
    rev = ""

    for letter in string:
        stack.push(letter)

    while not stack.is_empty():
        rev = rev + stack.top()
        stack.pop()

    return rev