"""
A simple module showing off for iterators

Author: Walker M. White (wmw2)
Date:   September 28, 2017 (Python 3 Version)
"""


def simple_iter(seq):
    """
    Prints out the first four elements of the sequence
    
    The function uses an iterator to traverse the sequence. If the sequence has less than 
    four elements, there will be an error.
    
    Parameter seq: the sequence to print out
    Precondition: seq a sequence (string or list)
    """
    theiter = iter(seq)
    x = next(theiter)
    print('Starting iterator')
    print(x)
    x = next(theiter)
    print(x)
    x = next(theiter)
    print(x)
    x = next(theiter)
    print(x)
    print('Done with iterator')


def sum(thelist):
    """
    Returns: the sum of all elements in thelist
    
    Parameter the list: the list to sum
    Precondition: thelist is a list of numbers (either floats or ints)"""
    result = 0
    
    theiter = iter(thelist)
    for x in theiter:
        result = result+x
        print('Adding '+str(x)+' yields '+str(result))
    
    return result