Wrap up sorting

Learn recursion, an alternative to iteration for repetition

Practice writing recursive functions

printmessage.py: A recursive example program that repeats a message.

countdown.py: A recursive program to analyze and discuss.

factorial.py: Recursive exercise to implement a factorial function.

list_reverse.py: Recursive exercise to reverse a list.

count_letter.py: Recursive exercise to count how many times a character appears in a string.

power.py: Recursive exercise to write a function that raises a number to a power.

sorted.py: Recursive exercise to determine if a list is in sorted order.