-CoderOilStation
课程类别：计算机
课程名：CPSC110 系统程序设计环节 Systematic Program Design
mt2-p6-solution
;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname mt2-p5-solution) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f () #t)))
(require spd/tags)
(require 2htdp/image)
(@assignment exams/2022w2-mt2/mt2-p6)
(@cwl ???) ;fill in your CWL here (same as for problem sets)
(@problem 1) ;do not edit or delete this line
(@problem 2) ;do not edit or delete this line
(@problem 3) ;do not edit or delete this line
(@problem 4) ;do not edit or delete this line
(@problem 5) ;do not edit or delete this line
(@problem 6) ;do not edit or delete this line
#|
In this problem you must complete the design of the function with an
appropriate @template-origin and function definition. You should consult
the mt2-p5-figure.pdf file which provides some additional help designing
the function.
YOU ARE NOT PERMITTED TO USE THE STEPPER AT ANY POINT IN THIS EXAM.
In this problem you must complete the design of a function by writing the
template origin tag and the function definition.
This problem will be autograded. NOTE that all of the following are required.
Violating one or more will cause your solution to receive 0 marks.
- The file MUST NOT have any errors when the Check Syntax button is pressed.
Press Check Syntax and Run often, and correct any errors early.
- The function definition MUST call one or more built-in abstract functions.
- The function definition MUST NOT be recursive.
- The function definition MUST NOT use any part of the recursive Natural
template or the (listof X) template. For instance,
- it must not include (cond [(empty? ... anywhere
- it must not include (cond [(zero? ... anywhere
- it must not include (first loc) anywhere
- You MUST NOT change or comment out any check-expects, and you must not
change the order of the existing check-expects, but you are free to add
new check-expects AFTER the existing check-expects.
- The result of the function must directly be the result of one of the
built-in abstract functions. So, for example, the following would not
be valid function body:
(define (foo x)
(empty? (filter ...)))
- For maximum credit your answer should be a composition of foldr and
build-list.
|#
(define SIZE 10)
(define COLOR "blue")
(define PEN "solid")
(@htdf pyramid)
(@signature Natural -> Image)
;; produce a pyramid with n-1 visible steps on each side (steps are 10x10)
(check-expect (pyramid 0) empty-image)
(check-expect (pyramid 1)
(beside/align "bottom"
(rectangle SIZE (* SIZE 1) PEN COLOR)
empty-image
(rectangle SIZE (* SIZE 1) PEN COLOR)))
(check-expect (pyramid 2)
(beside/align "bottom"
(rectangle SIZE (* SIZE 1) PEN COLOR)
(rectangle SIZE (* SIZE 2) PEN COLOR)
empty-image
(rectangle SIZE (* SIZE 2) PEN COLOR)
(rectangle SIZE (* SIZE 1) PEN COLOR)))
(check-expect (pyramid 3)
(beside/align "bottom"
(rectangle SIZE (* SIZE 1) PEN COLOR)
(rectangle SIZE (* SIZE 2) PEN COLOR)
(rectangle SIZE (* SIZE 3) PEN COLOR)
empty-image
(rectangle SIZE (* SIZE 3) PEN COLOR)
(rectangle SIZE (* SIZE 2) PEN COLOR)
(rectangle SIZE (* SIZE 1) PEN COLOR)))
(@template-origin fn-composition use-abstract-fn)
(define (pyramid n)
(foldr (lambda (r rnr)
(beside/align "bottom" r rnr r))
empty-image
(build-list n
(lambda (n)
(rectangle SIZE (* (+ n 1) SIZE) PEN COLOR)))))
