CSC 15 Lab 7:



1. Finish Horse Race.  The Horse Race program MUST be done before spring
   break.


2. Write the following additional functions.



a. 
   def countcaps(S):

This function should count and return the number of captial letters in string
S.  For example, countcaps("aBc3De") should return 2.  




b. def allupper(S):

This should be a boolean function that returns True if all alphabetical
letters in S are upper-case, and False otherwise.  For example,
allupper("abCd") should return False.  Note that unlike the "lowercase"
example done in class, you're not making the letters upper-case, just
checking if they're already upper-case.

c. Write a function to generate a random string of characters.  For
   this, first generate a number for the length, then construct the
   string one character at a time.  For each character, you can generate
   a random integer between ord("A") and ord("Z"), then convert it into
   a character.  You can limit the function to generate only capital
   letters.


c2. Write a function to generate random strings with just the characters
    "A", "C", "G" and "T".  This time, the length of the string should be
    determined by a parameter to the function (part c above can be a function
    that does not take any paramters).


d. One simple way to scramble a string is to "rotate the characters".
   For example, we can rotate each character 3 slots forward: A becomes
   D, B becomes E, C becomes F, etc.., W becomes Z, X becomes A (wrapping
   around), Y becomes B, and Z becomes C.

   If we rotate every character, then a string such as "AWE" will become
   "DZH".  

   Write a function

   def scramble(S,r): 

   That returns the scrambled form of string S by rotating each character
   r spots forward.  So scramble("AWE",3) should return "DZH". 

   To make things simpler, you may assume that the string contains only
   upper-case letters.


e. Write a function to descramble a string to recover the original.