6.25 Lab 3, Part 2: Rotate a letter for Caesar

Write a rotate() function that takes two parameters, a string intended to be one upper-case A-Z letter and an integer, and returns a string. *The returned string should be the *input letter rotated by the number of positions specified by the integer argument*. (The Romans of Caesar's time only used what today we call upper-case letters.)

So a call to rotate("C", 1) should return (return not print) the string D and a call to rotate(D, -1) should return the string "C". Rotation should "wrap around" the end of the alphabet, so rotate("Z", 3) should return "C".

Hints:

• It will be useful for you to use a string containing all the upper case letters in order. You probably want to use a variable assignment for this.
  • Then you can use the find() function discussed in Tuesday's lecture to find the index of a character in the alphabet (also described in Zybooks 7.1, which also has a lot of other stuff).
  • And indexing of strings
• You will want to use the remainder function % together with addition (+) to the get the wrapping around the end of the alphabet behavior. -Remember: Our lab and project assignments never use the Python input() statement unless we explicitly say so, which from here on out we will almost never do.