learning-haskell/04-basic-datatypes/4.9-chapter-exercises.md

Chapter Exercises

1. length :: [a] -> Int (Why not Integer?)
2. Answers:
   1. 5
   2. 3
   3. 2
   4. 5
3. (/) takes two Fractional types. length returns and Int which is not Fractional. (Float and Double are)
4. Use div instead: div 6 $ length [1, 2, 3]
5. Bool. True (Note: (+) has higher precedence)
6. Bool. False
7. Answers:
   1. Works. Bool. True
   2. Won't work. List needs to have elements of the same type.
   3. Works. Int. 5
   4. Works. Bool. False
   5. Won't work. (&&) needs two Bool's, 9 isn't one.
8. see src/chapter4.hs
9. see src/chapter4.hs
10. see src/chapter4.hs

Correcting syntax

see src/chapter4.hs

Match the function names to their types

1. (c)
2. (b)
3. (a)
4. (d)