- Language: Beginning Student
- Teachpack: none
- Lab3 Template (Remember to change the name of this file to your CNET id.)
0. Designing Functions on Lists
In this lab you will be designing functions which operate on lists.
- You must follow the Design Recipe for each function.
- You must prove to me you function works!!.
- Use helper functions. Your functions need to be readable for humans too!
1. Create a template
Create a design template for functions that operate on a generic list of
2. Processing Lists of Numbers
To find the minimum number on a list of numbers you
could find the minimum value on a list by first sorting the list in
increasing order, then selecting the first element of the list. But on
long lists this is extremely inefficient. Use you Design Template from
Part 1 to guide your construction. Test these functions thoroughly.
;; minimum: list-of-numbers -> number
;; find minimum value on alon
;; (define (minimum alon) ... )
;; remove-nums: list-of-numbers number -> list-of-numbers
;; remove all numbers less than num from alon
;; (define (remove-nums alon num) ... )
3. Help your Grader
Your grader needs help managing the list of student records.
I have defined a structure for a
which consists of a name and a grade. You need to provide a list of al
constructors and selectors:
;; a student is a
;; (make-student symbol symbol)
(define-struct student (name grade))
Design the following functions for your grader:
;; get-grade: list-of-students symbol -> symbol
;; given alost and name (of student) return grade if student on list
;; Return 'None if student not on list
;; (define (get-grade alost name) ...)
;; get-names: list-of-students symbol -> list-of-symbols
;; Return list of all names of students with given grade
;; (define (get-names alost grade)...)
;; update-grade: list-of-students name grade -> list-of-students
;; update alost by changing student-grade to grade for name
;; (define (update-student alost name grade) ... )
4. Binary to Decimal
list-of-bits is a list of numbers all of which are 0 or 1.
The bits are listed from least significant to most significant, so
you compute the decimal value of a list-of-bits as follows
;; (cons 1 (cons 0 (cons 1 (cons 1 empty))))
;; 1*20 + 0*21 + 1*22 + 1*23
;; == 13
Write the following function
;; bin->dec: list-of-bits -> number
;; convert alob to decimal value, assuming alob starts from least
;; significant bit to most significant bit
;; (define (bin->decs alob) ... )