diff options
Diffstat (limited to 'coding-exercises')
| -rw-r--r-- | coding-exercises/2/46.rkt | 46 | ||||
| -rw-r--r-- | coding-exercises/2/49.rkt | 110 |
2 files changed, 122 insertions, 34 deletions
diff --git a/coding-exercises/2/46.rkt b/coding-exercises/2/46.rkt index 4016ef7..91fad04 100644 --- a/coding-exercises/2/46.rkt +++ b/coding-exercises/2/46.rkt @@ -1,27 +1,27 @@ #lang racket -(require "../../shared/lists.rkt") - -(define (make-vect x y) - (cons x y)) -(define (xcor-vect v) - (car v)) -(define (ycor-vect v) - (cdr v)) - -(define (add-vect . v) - (make-vect - (fold-right + 0 (map xcor-vect v)) - (fold-right + 0 (map ycor-vect v)))) -(define (sub-vect . v) - (let ((xcors (map xcor-vect v)) - (ycors (map ycor-vect v))) - (make-vect - (- (car xcors) (fold-right + 0 (cdr xcors))) - (- (car ycors) (fold-right + 0 (cdr ycors)))))) -(define (scale-vect s v) - (make-vect (* s (xcor-vect v)) - (* s (ycor-vect v)))) - +;; (require "../../shared/lists.rkt") +;; +;; (define (make-vect x y) +;; (cons x y)) +;; (define (xcor-vect v) +;; (car v)) +;; (define (ycor-vect v) +;; (cdr v)) +;; +;; (define (add-vect . v) +;; (make-vect +;; (fold-right + 0 (map xcor-vect v)) +;; (fold-right + 0 (map ycor-vect v)))) +;; (define (sub-vect . v) +;; (let ((xcors (map xcor-vect v)) +;; (ycors (map ycor-vect v))) +;; (make-vect +;; (- (car xcors) (fold-right + 0 (cdr xcors))) +;; (- (car ycors) (fold-right + 0 (cdr ycors)))))) +;; (define (scale-vect s v) +;; (make-vect (* s (xcor-vect v)) +;; (* s (ycor-vect v)))) +(require "../../shared/pict.rkt") (define test-vec (make-vect 1 2)) (define test-vec2 (make-vect 3 4)) ((lambda () diff --git a/coding-exercises/2/49.rkt b/coding-exercises/2/49.rkt index 688364a..9ee7fe9 100644 --- a/coding-exercises/2/49.rkt +++ b/coding-exercises/2/49.rkt @@ -1,21 +1,109 @@ #lang racket -(require (only-in sicp-pict - paint - segments->painter)) (require "../../shared/pict.rkt") +(require "../../shared/lists.rkt") (define (outline frame) - (display frame) - (let ((corner - (add-vect + (let ((corner + (add-vect (edge1-frame frame) (edge2-frame frame))) (origin (origin-frame frame)) (e1 (edge1-frame frame)) (e2 (edge2-frame frame))) - (segments->painter - (list (make-segment origin e1) - (make-segment e1 corner) - (make-segment corner e2) - (make-segment e2 origin))))) + ((segments->painter + (list (make-segment origin e1) + (make-segment e1 corner) + (make-segment corner e2) + (make-segment e2 origin))) frame))) (paint outline) + +(define (x frame) + ((segments->painter + (list (make-segment (origin-frame frame) + (add-vect + (edge1-frame frame) + (edge2-frame frame))) + (make-segment (edge1-frame frame) + (edge2-frame frame)))) + frame)) +(paint x) + +(define (midpoint-segment s) + (let ((start (start-segment s)) + (end (end-segment s))) + (let ((midpoint + (make-vect + (/ (+ (xcor-vect end) (xcor-vect start)) 2) + (/ (+ (ycor-vect end) (ycor-vect start)) 2)))) + midpoint))) + +(define (enumerate-corners frame) + (list + (origin-frame frame) + (edge1-frame frame) + (add-vect + (edge1-frame frame) + (edge2-frame frame)) + (edge2-frame frame))) + +(define (close-line line-points) + (append line-points (list (car line-points)))) + +(define (enumerate-segments frame) + (map + (lambda (pair) + (make-segment (car pair) (cadr pair))) + (enumerate-windows + (close-line (enumerate-corners frame)) + 2))) + +(define (line-points->segments points) + (map + (lambda (pair) + (make-segment (car pair) (cadr pair))) + (enumerate-windows + points + 2))) + +(define (diamond frame) + ((segments->painter + (line-points->segments + (close-line + (map + midpoint-segment + (enumerate-segments frame))))) + frame)) +(paint diamond) + +(define (wave frame) + (let ((wave-points + (list + (make-vect 0.24 0) + (make-vect 0.37 0.5) + (make-vect 0.3 0.6) + (make-vect 0.15 0.5) + (make-vect 0 0.7) + (make-vect 0 0.85) + (make-vect 0.15 0.65) + (make-vect 0.35 0.7) + (make-vect 0.4 0.7) + (make-vect 0.3 0.85) + (make-vect 0.36 1) + (make-vect 0.57 1) + (make-vect 0.62 0.855) + (make-vect 0.55 0.7) + (make-vect 0.65 0.7) + (make-vect 1 0.35) + (make-vect 1 0.25) + (make-vect 0.55 0.52) + (make-vect 0.7 0) + (make-vect 0.55 0) + (make-vect 0.45 0.4) + (make-vect 0.34 0)))) + ((segments->painter + (append + (enumerate-segments frame) + (line-points->segments + (close-line + wave-points)))) frame))) +(paint wave) |