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Comp210: Principles of Computing and Programming
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;; ;; within-two?: number, number --> boolean ;; Are m,n less than 2 apart? ;; (Difference of exactly 2 returns false.) ;; (define (within-two? m n) (and (< (- m n) 2) (< (- n m) 2))) (within-two? 99.8 101) true (within-two? 5 -5) false (within-two? 7 7) true ;; ;; fastest-runner: nonnegative-number -> symbol ;; Given a distance to run (in meters), ;; return the fastest runner on the team. ;; (define (fastest-runner distance) (cond [(< distance 300) 'Marianne] [(and (>= distance 300) (< distance 1000)) 'Becca] [(and (>= distance 1000) (< distance 10000)) 'Suzy] [>= distance 10000) 'Yvonne])) "Test fastest-runner." (symbol=? (fastest-runner 10000) 'Yvonne) (symbol=? (fastest-runner 8000) 'Suzy) (symbol=? (fastest-runner 2000) 'Suzy) (symbol=? (fastest-runner 200) 'Marianne) (symbol=? (fastest-runner 999) 'Becca) ;; ;; lion-pop-later: nonnegative-number --> nonnegative-number ;; Given this year's lion-population, ;; returns next year's lion-population, according to the model specified on ;; Lab02) ;; (define (lion-pop-later pop-now) (cond ; Low population: 10% growth. [(< pop-now 800) (* 1.1 pop-now)] ; Moderate population: 2% growth. [(and (>= pop-now 800) (< pop-now 1100) (* 1.02 pop-now)] ; Overcrowding: -30% growth. [(>= pop-now 1100) (* 0.7 pop-now)])) "Test lion-pop-later" (= (lion-pop-later 0) 0) (= (lion-pop-later 100) 110) (= (lion-pop-later 700) 770) (= (lion-pop-later 800) 816) (= (lion-pop-later 1100) 770) (= (lion-pop-later 10000) 7000) (define-struct ppg (name color ferocity ca?)) ; ; A Powerpuff Girl ("ppg") is: ; (make-ppg symbol symbol number boolean) ; where name is the ppg's name, ; color is their color ; (presumably one of {'green,'blue,'red}, but perhaps different ; if new ppgs are ever created) ; ferocity is their ferocity index, a number. ; and ca? is whether or not they're conflict avoidant. "Examples of ppgs" (make-ppg 'Buttercup 'green 90 false) (make-ppg 'Blossom 'red 70 false) (make-ppg 'Bubbles 'blue 77 true) ;; ;; negotiates-well?: ppg -> boolean ;; Given a powerpuff girl, would she make a good negotiator? ;; (define (negotiates-well? a-ppg) (< (ppg-ferocity a-ppg) 80)) "Test negotiates-well?:" (negotiates-well? (make-ppg 'Buttercup 'green 90 false)) false (negotiates-well? (make-ppg 'Blossom 'red 70 false)) true (negotiates-well? (make-ppg 'Bubbles 'blue 77 true)) true ;;; Optional Challenge version: ;; negotiates-well-v2?: ppg -> boolean ;; Given a powerpuff girl, would she make a good negotiator? ;; (define (negotiates-well-v2? a-ppg) (or (ppg-ca? a-ppg) (and (> 80 (ppg-ferocity a-ppg)) (> (ppg-ferocity a-ppg) 20)))) ; Alternately: (< 20 (ppg-ferocity a-ppg) 80) #| Using cond, this could be written with: (cond [(ppg-ca? a-ppg) true] [(>= (ppg-ferocity a-ppg) 80) false] [(>= 20 (ppg-ferocity a-ppg)) false] [else true]) Sorry for the weird phrasing of the >=; Unfortunately, in .html files the less-than would get swallowed. |# (negotiates-well-v2? (make-ppg 'buttercup 'green 90 false)) false (negotiates-well-v2? (make-ppg 'blossom 'red 70 false)) true (negotiates-well-v2? (make-ppg 'bubbles 'blue 77 true)) true ; We want to test somebody who is a conflict-avoidant but ; not between 20 & 80 ferocity: (negotiates-well-v2? (make-ppg 'didi 'rainbow 15 true)) true ; Also test ferocity below 20 and not avoidant: (negotiates-well-v2? (make-ppg 'dexter 'white 10 false)) false ;; two-can-beat-up?: ppg, ppg, number --> boolean ;; Can two ppg's combined take on a villain with toughness "v-toughness"? ;; (define (two-can-beat-up? p1 p2 v-toughness) (>= (+ (ppg-ferocity p1) (ppg-ferocity p2)) v-toughness)) ; Note: perhaps adding the ferocities is not a good ; model; perhaps there is synergy for increased ferocity, ; or diminishing returns as you add ferocity. ; Ah well, this is a good model for now, ; and we can tweak it later for increased reality. "Test two-can-beat-up?" (two-can-beat-up? (make-ppg 'buttercup 'green 90 false) (make-ppg 'bubbles 'blue 77 true) 110) true ; Test when villain is totally wimpy: (two-can-beat-up? (make-ppg 'buttercup 'green 90 false) (make-ppg 'bubbles 'blue 77 true) 23) true (two-can-beat-up? (make-ppg 'buttercup 'green 90 false) (make-ppg 'bubbles 'blue 77 true) 190) false ; Test when villain is between the two ppg's ferocity: (two-can-beat-up? (make-ppg 'buttercup 'green 90 false) (make-ppg 'bubbles 'blue 77 true) 84) true ; Test when villain is exactly the sum of the two ppg's ferocity: ; (Presumably both sides succesfully beat each other up.) (two-can-beat-up? (make-ppg 'buttercup 'green 90 false) (make-ppg 'bubbles 'blue 77 true) (+ 90 77)) true ;;;;;;;;;;;;;;;; "Optional Challenge problems" "(further tests should be true, or instances of structs.)" ;; (define-struct villain (name power always-hungry? iq weakness)) ;; ;; A villain is: ;; (make-villain [symbol] [number] [boolean] [number] [symbol]) ;; where power is the power-rating, iq is an IQ. ;; weakness describes the villain's achilles heel. ;; name and always-hungry? are self-evident. ; Examples of data: (make-villain 'fuzzy-lumpkins 90 true 35 'witty-banter) (make-villain 'mojo-jojo 35 false 190 'soliliquizing) #| ;;;; TEMPLATE ;; villain-handler: villain --> ?? ;; (define (villain-handler a-villain) ..(villain-name a-villain) ..(villain-power a-villain) ..(villain-iq a-villain) ..(villain-always-hungry? a-villain) ..(villain-weakness a-villain) ) |# ;; can-handle?: ppg, villain -> boolean ;; returns whether a-ppg could handle a-villain, one-on-one. ;; Peaceful resolutions count as 'handling'. ;; (define (can-handle? a-ppg a-villain) (or (>= (ppg-ferocity a-ppg) (villain-power a-villain)) ; Combat resolution. (and (ppg-ca? a-ppg) (> (villain-iq a-villain) 150)))) ; Negotiation. (boolean=? (can-handle? (make-ppg 'bubbles 'blue 77 true) (make-villain 'fuzzy-lumpkins 90 true 35 'witty-banter)) false) (boolean=? (can-handle? (make-ppg 'bubbles 'blue 77 true) (make-villain 'mojo-jojo 35 false 190 'soliliquizing)) true) ; More test cases needed, to be confident. ;;;;;;;;;; ; Data definition: ; A Townsvillite is: ; - a ppg, or ; - a villain. ;; is-rash? : Townsvillite -> boolean ;; Is the Townsvillite prone to ill-considered, hot-tempered actions? ;; (define (is-rash? townie) (cond [(ppg? townie) (not (ppg-ca? townie))] [(villain? townie) (> 120 (villain-iq townie))] [else (error 'is-rash? "Expected a Townsvillite, got ~s." townie)])) (boolean=? (is-rash? (make-ppg 'bubbles 'blue 77 true)) false) (boolean=? (is-rash? (make-villain 'mojo-jojo 35 false 190 'soliliquizing)) false) (boolean=? (is-rash? (make-villain 'fuzzy-lumpkins 90 true 35 'witty-banter)) true) ;; More test cases needed, to be confident. (define-struct citizen (name gender)) ; A Citizen is: ; (make-citizen [symbol] [symbol]) ; where gender is one of {'male, 'female}. ; Example data: (make-citizen 'mayor 'male) (make-citizen 'teacher 'female) ;What is her name? Email ian@rice, thx. ;; Include citizen in the definition of Townsvillite, ;; and correspondingly update is-rash?: ; A Townsvillite is: ; - a ppg, or ; - a villain, or ; - a citizen. ;; is-rash? : Townsvillite -> boolean ;; Is the Townsvillite prone to ill-considered, hot-tempered actions? ;; (define (is-rash? townie) (cond [(ppg? townie) (not (ppg-ca? townie))] [(villain? townie) (> 120 (villain-iq townie))] ;[(citizen? townie) false] [(citizen? townie) false] [else (error 'is-rash? "Expected a Townsvillite, got ~s." townie)])) (boolean=? false (is-rash? (make-citizen 'mayor 'male))) ; Plus we should repeat the previous test-cases, ; to see if bugs were introduced. (boolean=? (is-rash? (make-ppg 'bubbles 'blue 77 true)) false) (boolean=? (is-rash? (make-villain 'mojo-jojo 35 false 190 'soliliquizing)) false) (boolean=? (is-rash? (make-villain 'fuzzy-lumpkins 90 true 35 'witty-banter)) true)
Last Revised Tuesday, 24-Aug-2004 13:49:02 CDT
©2004 Stephen Wong and Dung Nguyen