CS 2010 Lab 2 Instructor Plan

  1. Evaluate by hand:
    (define (h x)
      (* 7 x))
    (h 10)
  2. Evaluate by hand:
    (define (f a)
      (* 7 (cond
    	[(= a 3) 9]
    	[(= a 4) 10])))
    (f 3)
  3. Evaluate by hand:
    (define (t a)
      (* 7 (cond
    	[(= a 3) 9]
    	[(= a 4) 10]
    	[else 11])))
    (t 5)
  4. Evaluate by hand:
    (define (g a b c)
      (make-posn 10 (posn-y (cond
    			 [(= c 12) a]
    			 [else b]))))
    (g (make-posn 1 2) (make-posn 3 4) 11)
  5. Write the function order which takes two numbers and produces a posn containing the two numbers. The X part of the posn should contain the smaller number, and the Y part the larger.
  6. Write the function max-part, which takes a posn and returns either the X or Y part, whichever is larger.

For the programs, don't bother with a lab2 handin.

We haven't yet talked about the design recipe for compound data in lecture. So you should suggest the following guideline: when they're writing a function that consumes a posn p, they should write (posn-x p) and (posn-y p) as a start for the function body.

Last update: Wednesday, August 27th, 2003