Homework 9: File I/O

Write two functions:

1. The first function, list_output(), should write each element of a list to a separate line of a file. Each item should be prefixed by its index. For example:

items = ['a', 'b', 'c']
list_output("letters.txt", items)

should create the following file:

0 a
1 b
2 c

1. The second function, list_input(), should read in a file in the above format and reconstruct the original list.