Comp 200 hw01: Finger exercises

Due in class 01.Jan.24 (Wed)

• First, you need to do some account-setup.
  • Run register comp200 on your owlnet account (details)
  • Run pcpasswd on your owlnet account (from either short-eared or long-eared; details).
  • Sign in to the the course grade database (not yet on-line)
• Look at the class newsgroup (link from the main class web page), find the posting titled hw01 question (spring '01), and e-mail me the answers to those questions. (details on reading news)
• Start DrScheme (details), and experimentally type a few things into the top half, and press "execute". (Nothing to turn in.)
• What do the following Scheme expressions evaluate to? Verify by typing them into Dr.Scheme, but first try to predict the answer.
  1. (+ 22 (* 4 7) -2)
  2. (- 4 3 2)
  3. (define pi 3)
  4. pi
  5. (define (square n) (* n n)))
  6. (square 7)
  7. (define (area r) (* pi r r)))
  8. (area pi)
  9. area
  10. (and true (or false true))
  11. (if false (if false 3 4) (if true 5 6))
  12. (if (= 3 2) (/ 1 0) (/ 1 2))
  13. (+ false true)
  You can print your answers by hand, or if you type these in drscheme's definitions window (the top half), then cut/paste the outputs from the interactions window up to the definitions, you can just "print interactions window".

• Write Scheme versions of the following mathematical formulae, and test each on at least two inputs (one of which should be some sort of borderline case, e.g. 32 degrees fahrenheit).
  1. celc( f ) = (5/9)(f-32)
  2. dist( a, t ) = 1/2 a t²
  3. my-abs( x ) = x, if x >= 0, or -x if x < 0.
  Again, type these in the definitions window, including test cases, then cut/paste the results up to the top half to print.