CSM CSCI-400

Racket Homework #01

(Last Mod: 17 December 2013 13:16:53 )

Purpose:

Learn about functional programming using Scheme
Practice recursion. Review chapter slides on recursion.
Learn about first-class procedures

This homework is to be done individually. For simplicity, put all three parts in the same file.

Document your code well. If the grader has difficulty following your reasoning, they will take away from the 25% allocated toward Effort.

Preparation:

Open Dr. Racket
Set the Language to Full Swindle
Do the Scheme exercises (You do not need to turn these in since the solutions are provided for you).
Do a google search to learn about string functions, including string->symbol, symbol->string and string-append.

Part I: Process a list recursively. 10 points.

Write a function named containsAnywhere

Use the unitTest below to verify your function is correct.

(define (unitTest)
  (and 
   (containsAnywhere 'a '(a))
   (containsAnywhere 'a '(b a))
   (not (containsAnywhere 'a '(c d)))
   (containsAnywhere 'a '((a) b))
   (containsAnywhere 'b '((c d e) (g b e)))
   (containsAnywhere 'b '((c d e) (g (b) e)))
   (not (containsAnywhere 'x '((c d e) (g (b) e))))
   (containsAnywhere 'f '((c d e) (g (b) e) f))
   (not (containsAnywhere 'h '((c d e) (g (b) e) f)))
   ))

Part II: Modify a list recursively. 10 points.

Write a function named removeAll that takes an item to be removed and a list and returns the list with all instances of that item removed.

Use the unitTest below to verify your function is correct.

(define (unitTest2)
  (and 
   (equal? (removeAll 'a '(b a c)) '(b c))
   (equal? (removeAll 'a '((b a c d))) '((b c d)))
   (equal? (removeAll 'b '((b a c d (f)))) '((a c d (f))))
   (equal? (removeAll 'b '((b a c d (f b)))) '((a c d (f))))
   (equal? (removeAll 'b '((b a c d (f (b))))) '((a c d (f ()))))
   (equal? (removeAll 'b '((b a c d (f (b g))))) '((a c d (f (g)))))
   ))

Part III: First class procedures. 20 points.

In this homework assignment you will be creating a small conversion "calculator" that will allow you to easily define and call conversion functions. The image below shows two executions of the calculator, one converting feet to meters, one converting a temperature from fahrenheit to celcius.

Specific requirements:

(8) Define at least four functions that perform conversions. Each function should follow the naming convention: unit1-to-unit2, e.g., feet-to-meters.
(12) Write a calculator function that:
- prompts and accepts the first unit
- prompts and accepts the second unit
- creates the appropriate function name (e.g., for unit1=feet and unit2=meters, function name will be feet-to-meters). Hint: use string functions referenced above.
- use eval or apply + eval to convert a value entered by the user.
Error handling is not required (e.g., if user enters units and no function exists, program will simply abort).

Hints:

Make use of the eval-print loop to test the various components of your function, such as converting a symbol to a string, appending a string, etc.
eval takes a list, e.g., (eval (+ 3 4)). If you do (eval +) it returns #. If you did (eval 'feet-to-meters) it would return a procedure. You need to do, for example, (eval (feet-to-meters 4)).
Be sure to use eval or apply. DO NOT just write up a function with an big if-else or cond statement to determine which function to execute.

Submission:

Put all of your solutions into a single file.

Name your program CS400_UserID_R_01.rkt (as usual, UserID is replaced with YOUR CSM User ID)

Submit your .rkt file on Blackboard.