Assignment 1
due
Copy the program below into your REPL editor. There are 5 functions to
write, described by comments right above them. There is also a test
program which should run when you hit the play button. Its initial
output will indicate many test failures and a few coincidental
successes (labeled OK), but there should not be any compiler errors:
FAIL line 46 : 0.0 ~= 4.1887902047863905 FAIL line 47 : 0.0 ~= 2144.660584850632 FAIL line 48 : 5.0 ~= 118.09733552923254 FAIL line 50 : 0.0 ~= 32.0 FAIL line 51 : 0.0 ~= 212.0 FAIL line 52 : 0.0 ~= 98.6 FAIL line 54 : 0.0 ~= 100.0 OK line 55 : 0.0 ~= 0.0 FAIL line 56 : 0.0 ~= 37.0 FAIL line 58 : expected true FAIL line 59 : expected true FAIL line 60 : expected true FAIL line 61 : expected true OK line 62 : expected false OK line 63 : expected false FAIL line 65 : '?' == 'N' FAIL line 66 : '?' == 'k' FAIL line 68 : "?????" == "Uryyb" FAIL line 69 : "?????????????????????????" == "To get to the other side!"
Details about how to submit will be posted later. Just copy/paste
into an email, or into a document and then attach to email. We’ll try
to have a more sophisticated submission mechanism for assignment 2.
import GHC.Stack import Data.Char {- Look up the formula for the volume of a sphere of a given radius. Code it below. The zero is a placeholder, so you should replace that with an expression involving r. -} volumeSphere r = 0 {- Convert a temperature c from the Celsius to Fahrenheit scale. -} celsiusToFahrenheit c = 0 {- Convert a temperature f from Fahrenheit to Celsius. -} fahrenheitToCelsius f = 0 {- Determine whether the given string is a palindrome, and just return a Bool. A palindrome is the same forward or backward (reversed). For now we're only testing this with simple words like "ABBA" and "racecar" but we will also think about requiring only alphabetic characters to match, and allowing matches to be case-insensitive, so we can detect this as a palindrome: "Was it a car or a cat I saw?" -} palindrome str = False {- A "rot13" encoding of text is one where each character is rotated 13 places around the alphabet, so "A" becomes "N", and "N" becomes "A". This function should take a character and return a character. Non-alphabetic characters should be returned as-is. To apply to an entire string, we just use 'map' (see the test program). This requires some more advanced Haskell techniques and library functions, that we will cover on Monday 9/9. -} rot13 c = '?' -- Test program -- don't change anything below main = do volumeSphere 1 @?~ 4.1887902047863905 volumeSphere (3 + 5) @?~ 2144.660584850632 volumeSphere 3 + 5 @?~ 118.09733552923254 celsiusToFahrenheit 0 @?~ 32 celsiusToFahrenheit 100 @?~ 212 celsiusToFahrenheit 37 @?~ 98.6 fahrenheitToCelsius 212 @?~ 100 fahrenheitToCelsius 32 @?~ 0 fahrenheitToCelsius 98.6 @?~ 37 assertTrue $ palindrome "racecar" assertTrue $ palindrome "ABBA" assertTrue $ palindrome "" assertTrue $ palindrome "x" assertFalse $ palindrome "ab" assertFalse $ palindrome "abb" rot13 'A' @?= 'N' rot13 'x' @?= 'k' map rot13 "Hello" @?= "Uryyb" map rot13 "Gb trg gb gur bgure fvqr!" @?= "To get to the other side!" -- Test framework -- don't change anything below infix 1 @?~, @?= (@?~) :: (HasCallStack, Fractional a, Ord a, Show a) => a -> a -> IO () (@?~) a1 a2 = putStrLn $ testBinRel callStack "~=" (\a b -> abs (a-b) <= 0.00001) a1 a2 (@?=) :: (HasCallStack, Eq a, Show a) => a -> a -> IO () (@?=) a1 a2 = putStrLn $ testBinRel callStack "==" (==) a1 a2 assertTrue :: HasCallStack => Bool -> IO () assertTrue expr = putStrLn $ testReport callStack expr "expected true" assertFalse :: HasCallStack => Bool -> IO () assertFalse expr = putStrLn $ testReport callStack (not expr) "expected false" testBinRel stack repr predicate a1 a2 = testReport stack (predicate a1 a2) (unwords [show a1, repr, show a2]) testReport stack pass descr = unwords [ if pass then " OK " else "FAIL" , "line" , getLineNum stack , ":" , descr ] getLineNum stack = case getCallStack stack of [] -> "?" (_, loc):_ -> show (srcLocStartLine loc)