Homework 2

CS18

60 pts., due Mar. 1

In an attempt to discover a new secret code, a programmer thought of the following scheme: ``I could divide a string into halves and interchange them. In fact, I could do this recursively, dividing each half in half and interchanging the pieces. That ought to mix up things pretty well.'' If you think about it for a while, you'll discover another nice feature of this scheme: the same algorithm can be used for coding and decoding.

1. Write a C++ function which implements this function as described by the programmer. Write a small driver program which allows you to test your function.
2. Verify that your function can also decode a coded string.
3. Unfortunately, this algorithm doesn't mix up the characters of a string very well at all. What does the algorithm do? What would be the result of applying this algorithm to the strings "alligator" and "able was i ere i saw elba"?
4. Write a simpler recursive function (and driver program) that does what this function does.

Turn in copies of your source code and example runs with the input and output.