What to hand in, and how to hand it in, and when

• Make a directory ~/cs2613/assignments/A1 (i.e. in your git repo for this class). All files related to this assigment should be saved in that directory.
• Make sure you commit and push all your work using git before 16:30h on Tuesday September 26

Marking

• This assignment will be worth 4% of your final grade.
• You will be marked on the last version pushed to coursegit
• You will be marked on

  adequacy of tests

  complete coverage is a minimum requirement

  coding style

  For racket, we follow official racket code layout. If you don't fight DrRacket too much, this should be easy.

  correctness

  Obviously your code should should do what it is supposed to.

  idiomatic racket

  This assignment is about structs and functions in racket; you shouldn't need anything else.

• For a detailed marking scheme, see racket-assignment

Questions

Solve the following (Exercise 8 from FICS) using #lang htdp/bsl

Part 1

Using the clock struct defined by:

    (define-struct clock (hours mins secs))

to represent 24-hour time (midnight is 00:00:00, one second before is 23:59:59), write the function tick that consumes a clock struct c and produces the clock struct representing the time one second after the time represented by c. Use modular arithmetic (i.e. the functions modulo, remainder, and/or quotient)

Here are some test cases to help explain how the function should work

(check-expect (tick (make-clock 23 59 59))
              (make-clock 0 0 0))
(check-expect (tick (make-clock 23 58 59))
              (make-clock 23 59 0))
(check-expect (tick (tick (make-clock 23 59 58)))
              (make-clock 0 0 0))

Part 2

Define a second function tick* that does the same thing (in particular passes all of the same tests) as tick, but does not use modular arithmetic.