Chapter 5 Quiz

No notes, no book, do by yourself.

Stone Age

Write each of the following, using nothing but “stone age” tools: guards, patterns, == (etc), :, ++. No length, head, tail, etc.

1. myintercalate :: String -> [String] -> String. Given a separator and a list of strings, create a string containing the separator in between each of the strings (but not before the first or after the last).

    myintercalate ", " ["Witch","Bat","Broom"] == "Witch, Bat, Broom"
   

2. myfindGE :: Int -> [Int] -> [Int]. a list of everything greater than or equal to the first argument.

    myfindGE 5 [3,13,8,4,9] == [13,8,9]
   

Bronze Age

Here you are allowed to use tools.

1. boxMaker :: Int -> String. Make a function to create an square.

   Calling boxMaker 5 gives the string

    "xxxxx\nx   x\nx   x\nx   x\nxxxxx"
   

   to see this more beautifully, print it with putStrLn in your main method.

    main = do putStrLn $ boxMaker 5 
   

   (Use \n in a string to go to the next line.) The output looks like this:

    xxxxx
    x   x
    x   x
    x   x
    xxxxx
   

2. alphaBox :: String -> String. Make a square using the letters from the word provided. Add extra x’s at the end if needed to make a square. Omit spaces in the input from your box.

    alphaBox "Fox in a Box Rox"
   

   prints out as

     Foxi
     x  n
     o  a
     RxoB