bottles.md

Placeholder For Bottles Solutions

Here's a Haskell version for fun:

#!/usr/bin/env runghc

countWith :: [Integer]
countWith = reverse [0..99]

main :: IO ()
main = putStr $ concatMap output countWith

output :: Integer -> String
output n = concat [lookAtBottles n, "\n", passBottles (n - 1), "\n\n"]

noun :: Integer -> String
noun 1 = "bottle"
noun _ = "bottles"

lookAtBottles :: Integer -> String
lookAtBottles 0 = "No more bottles of beer on the wall, no more bottles of beer."
lookAtBottles n = concat [s, " ", b, " of beer on the wall, ", s, " ", b, " of beer."]
  where
    s = show n
    b = noun n

passBottles :: Integer -> String
passBottles n | n == (-1) = "Go to the store and buy some more, 99 bottles of beer on the wall."
              | n == 0 = "Take it down and pass it around, no more bottles of beer on the wall."
              | n > 0 = "Take one down and pass it around, " ++ s ++ " " ++ (noun n) ++ " of beer on the wall."
              | otherwise = error $ "Invalid bottle count: " ++ s
  where
    s = show n

Nice. I'm glad @sw17ch went with Haskell because I'm curious to see how the type system plays with some of the variations.

Are these all the conditionals, or did I miss any? (I'm not counting the exception because I don't think that code path is ever actually hit in the tests..)

• lookAtBottles: n == 0
• lookAtBottles: n != 0
• noun: n != 1
• noun: n == 1
• passBottles: n - 1 == -1
• passBottles: n - 1 == 0
• passBottles: n - 1 > 0

Here's mine in Groovy. Bryan and I have talked about this before and I like his approach of handling the 3 special cases completely separately to reduce some of the complexity.

class Bottles {
    def verse(n) {
        switch (n) {
            case 0:
                return """\
No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
"""
            case 1:
                return """\
1 bottle of beer on the wall, 1 bottle of beer.
Take it down and pass it around, no more bottles of beer on the wall.
"""
            case 2:
                return """\
2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.
"""
            default:
                return """\
${n} bottles of beer on the wall, ${n} bottles of beer.
Take one down and pass it around, ${n-1} bottles of beer on the wall.
"""
        }
    }

    def verses(first, last) {
        def song = ""
        (first..last).each { song += verse(it) + "\n" }
        song
    }

    def sing() {
        verses(99, 0)
    }
}

Yeah Zach, we have talked about this one sooooo much in the past, I feel like I know where this might be going....

class Bottles

  def sing
    verses 99, 0
  end

  def verses start, finish
    result = ""
    start.downto finish do |i|
      result += "#{verse i}\n"
    end
    result
  end

  def verse number
    case number
    when 0
      "No more bottles of beer on the wall, no more bottles of beer.\n" \
      "Go to the store and buy some more, 99 bottles of beer on the wall.\n"
    when 1
      "1 bottle of beer on the wall, 1 bottle of beer.\n" \
      "Take it down and pass it around, no more bottles of beer on the wall.\n"
    when 2
      "2 bottles of beer on the wall, 2 bottles of beer.\n" \
      "Take one down and pass it around, 1 bottle of beer on the wall.\n"
    when 3..99
      "#{number} bottles of beer on the wall, #{number} bottles of beer.\n" \
      "Take one down and pass it around, #{number - 1} bottles of beer on the wall.\n"
    end
  end
end

...and F#...cause...I'm an asshole

type Bottles() =

  member x.verse(number) = 
    match number with
      | 0 -> "No more bottles of beer on the wall, no more bottles of beer.\n\
              Go to the store and buy some more, 99 bottles of beer on the wall.\n"
      | 1 -> "1 bottle of beer on the wall, 1 bottle of beer.\n\
              Take it down and pass it around, no more bottles of beer on the wall.\n"
      | 2 -> "2 bottles of beer on the wall, 2 bottles of beer.\n\
              Take one down and pass it around, 1 bottle of beer on the wall.\n"
      | _ -> sprintf "%d bottles of beer on the wall, %d bottles of beer.\n\
                      Take one down and pass it around, %d bottles of beer on the wall.\n" number number (number - 1)

  member x.verses(start, finish) =
    if start = finish then sprintf "%s\n" (x.verse finish)
    else sprintf "%s\n%s" (x.verse start) (x.verses((start - 1), finish))

  member x.sing() =
    x.verses(99, 0)