Problems 1

Basic Expressions and Functions

  1. Give the type and value of each of the following expressions. For example, given the expression 2+2, the answer should be written as 4 :: Int. Note, some expressions may be errors.

  1. Given the following definition of the function f, simplify the expression f (f 1 2) (f 3 4), showing all your steps.
  2. f :: Int -> Int -> Int

    f x y = 2*x + 3

  3. Write a function isLetter :: Char -> Bool that determines whether its argument is a letter of the alphabet.
  4. Write a function capitalise :: String -> String that makes all the letters upper case.
  5. Write a function that determines whether or not one string is the prefix of another string.
  6. Write a function that occurs :: Int -> [Int] -> Int that returns the number of times a given number occurs in a list.
  7. Write a function reverse that reverses a string.
  8. Write a function palindrome :: String -> Bool that determines whether its argument is a palindrome. A palindrome is a string which is the same when you reverse it; for example, abccba is a palindrome, but abcca is not.