;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-advanced-reader.ss" "lang")((modname |29.3|) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #t #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp")))))
;norm : vector -> number
;Produces the square root of the sum of the numbers in avector.

(define (norm avector)
  (sqrt (sum-of-squares avector 0)))

;sum-of-squares : vector N -> number
;Given avector and i, square the element in avector from [i,vector-length) and then sum them 

(define (sum-of-squares avector i)
  (cond
    [(= (vector-length avector) i) 0]
    [else (+ (sqr (vector-ref avector i))
             (sum-of-squares avector (add1 i)))]))

;vector-contains-doll? : (vectorof symbols) -> boolean
;Given avector, determine if it contains 'doll.

(define (vector-contains-doll? avector)
  (vector-contains-doll?-aux avector 0))

;vector-contains-doll?-aux : (vectorof symbols) N -> boolean
;Given avector and i, determine if avector contains 'doll.

(define (vector-contains-doll?-aux avector i)
  (cond
    [(= (vector-length avector) i) false]
    [else (or (symbol=? (vector-ref avector i) 'doll)
              (vector-contains-doll?-aux avector (add1 i)))]))
(define vector2 (vector 'robot
                        'car
                        'eraser
                        'pen
                        'motorcycle
                        'bicycle
                        'helmet
                        'monitor
                        'dolly
                        'policeman
                        'diamond))
(vector-contains-doll? vector2)