[プログラミング入門　- Rubyを使って -](http://www.ie.u-ryukyu.ac.jp/~kono/software/s04/tutorial/)の練習問題

1.rb

puts "1年は#{365 * 24}時間です"

puts "10年間は#{60 * 24 * 365 * 10}分です"

puts "生まれてから#{Time.new - Time.mktime(1986, 1, 1)}秒経っている"

puts "80年生きるとして、#{(80 * 365) / 7}枚ぐらいかな"

puts "10億3400万秒生きてるとしたら#{1034000000 / 60 / 60 / 24 / 365}歳"

10.rb

# おじいさんの時計
def grandfathersClock
  h = Time.now.hour % 12
  h = 12 if h.zero?

  h.times{yield}
end

# プログラムロガー
def log(description)
  puts "開始 \"#{description}\"..."
  ret = yield
  puts "...\"#{description}\" 終了, 返り値は: #{ret}"
end


# プログラムロガー改良版
$nestingDepth = 0
def log_improved(description)
  indent = "  " * $nestingDepth
  $nestingDepth += 1

  puts "#{indent}開始 \"#{description}\"..."
  ret = yield
  puts "#{indent}...\"#{description}\" 終了, 返り値は: #{ret}"

  $nestingDepth -= 1
  ret
end

4.rb

# フルネームで挨拶
puts '姓入力して'
last_name = gets.chomp
puts '名入力して'
first_name = gets.chomp
puts "こんにちは、#{first_name + ' ' + last_name}"

# ベターな数字
puts '好きな数は？'
ans = gets.chomp.to_i
puts "それより#{ans + 1}のがよくない？"

5.rb

# 怒ったボス
puts '何が望みだ？'
ans = gets.chomp
puts "なにぃ、\"#{ans}\"だとー！！おまえは首だ！！"

# 目次
linewidth = 60
puts '目次'.center linewidth
puts ''
puts '1章: 数'  .ljust(linewidth/2) + 'p. 1'  .rjust(linewidth/2)
puts '2章: 文字'.ljust(linewidth/2) + 'p. 72' .rjust(linewidth/2)
puts '3章: 変数'.ljust(linewidth/2) + 'p. 118'.rjust(linewidth/2)

6.rb

# 99 Bottles of Beer on the Wall
def pluralize(n, singular)
  n == 1 ? singular : singular + 's'
end

99.downto(1).each{|i|
  puts "#{i} #{pluralize(i, 'bottle')} of beer on the wall"
  puts "#{i} #{pluralize(i, 'bottle')} of beer"
  puts "Take one down and pass it around"
  puts "#{i - 1} #{pluralize(i-1, 'bottle')} of beer on the wall"
  puts ''
}

# 耳の遠いおばあちゃん
puts 'なんじゃ?'
while true
  ans = gets.chomp

  if ans == ans.upcase
    break if ans == 'BYE'

    puts "いやー、#{1930 + rand(21)}年以来ないねー!"
  else
    puts 'は?! もっと大きな声で話しておくれ、坊や!'
  end
end
puts 'じゃあの'

# さみしがりやの耳の遠いおばあちゃん
def gramma(bye_count)
  return if bye_count >= 3

  ans = gets.chomp

  if ans == ans.upcase
    if ans == 'BYE'
      gramma(bye_count + 1)
    else
      puts "いやー、#{1930 + rand(21)}年以来ないねー!"
      gramma(0)
    end
  else
    puts 'は?! もっと大きな声で話しておくれ、坊や!'
    gramma(0)
  end
end

puts 'なんじゃ?'
gramma(0)
puts 'じゃあの'

# うるう年
def leap_year?(year)
  ((year % 400).zero?) || ((year % 4).zero? && (not ((year % 100).zero?)))
end

puts '開始は?'
start_year = gets.chomp.to_i
puts '終わりは?'
end_year = gets.chomp.to_i

(start_year..end_year).select{|y| leap_year? y}.each{|y| puts y}

7.rb

# 入力された値をアルファベット順に並べ替えて出力する
ary = []
while true
  elem = gets.chomp

  break if elem == ''

  ary << elem
end
ary.sort.each{|e| puts e}

# 目次を表示するプログラム配列版
linewidth = 60
puts '目次'.center linewidth
content = [['1章: 数', 'p. 1'], ['2章: 文字', 'p. 72'], ['3章: 変数', 'p. 118']]
content.each{|a| puts a[0].ljust(linewidth/2) + a[1].rjust(linewidth/2)}

8.rb

# thousand, million, billion, trillion追加済み拡張版
def englishNumber(number)
  return '負でない数を入力してください.' if number < 0
  return 'zero' if number == 0

  numString = ''

  onesPlace = ['one',     'two',       'three',    'four',     'five',
               'six',     'seven',     'eight',    'nine']
  tensPlace = ['ten',     'twenty',    'thirty',   'forty',    'fifty',
               'sixty',   'seventy',   'eighty',   'ninety']
  teenagers = ['eleven',  'twelve',    'thirteen', 'fourteen', 'fifteen',
               'sixteen', 'seventeen', 'eighteen', 'nineteen']

  left  = number

  # 単位(?)の追加はここに
  [["trillion", 1000000000000],
   ["billion",  1000000000],
   ["million",  1000000],
   ["thousand", 1000]].each{|a|
    key, value = a[0], a[1]
    write = left / value
    left  = left - (write * value)

    if write > 0
      num = englishNumber(write)
      numString = numString + num + ' ' + key

      if left > 0
        numString = numString + ' '
      end
    end
  }

  write = left / 100
  left  = left - (write * 100)

  if write > 0
    numString = numString + onesPlace[write-1] + ' hundred'

    if left > 0
      numString = numString + ' '
    end
  end

  write = left / 10
  left  = left - (write * 10)

  if write > 0
    if ((write == 1) and (left > 0))
      numString = numString + teenagers[left-1]

      left = 0
    else
      numString = numString + tensPlace[write-1]
    end

    if left > 0
      numString = numString + '-'
    end
  end

  write = left
  left  = 0

  if write > 0
    numString = numString + onesPlace[write-1]
  end

  numString
end

# weddigNumberは略

# ninety-nine Bottles of Beer on the Wall
def pluralize(n, singular)
  n == 1 ? singular : singular + 's'
end

99.downto(1).each{|i|
  eng_num = englishNumber(i)
  puts "#{eng_num} #{pluralize(i, 'bottle')} of beer on the wall"
  puts "#{eng_num} #{pluralize(i, 'bottle')} of beer"
  puts "Take one down and pass it around"
  puts "#{englishNumber(i-1)} #{pluralize(i-1, 'bottle')} of beer on the wall"
  puts ''
}

9.rb

y, m, d = 1986, 1, 1

# いつ10億秒歳になるか
puts Time.mktime(y, m, d) + 1000000000

# 今何歳か
puts "今#{((Time.new - Time.mktime(y, m, d)) / (60 * 60 * 24 * 365.25)).to_i}歳ぐらい"

# OrangeTreeクラス
class OrangeTree
  def initialize
    @height = 1
    @orangeCount = 0
    @dead = false
    @age = 0
  end

  def height
    puts "#{@height}メートル"
  end

  def oneYearPasses
    if @dead
      puts "枯れちゃってるので何もないよ"
      return
    end

    @orangeCount = 0
    @age += 1

    if die?
      @dead = true
    else
      grow

      produce if grown?
    end
  end

  def countTheOranges
    "#{@orangeCount}個の実が成っている"
  end

  def pichAnOrange
    if @orangeCount > 0
      @orangeCount -= 1
      puts "おいしー"
    else
      puts "実が無いよー"
    end
  end

  private

  def die?
    @age > 10
  end

  def grown?
    @age > 3
  end

  def grow
    @height += 1
  end

  def produce
    @orangeCount = @age
  end
end

# 赤ちゃんドラゴンと会話(Dragonの定義は省略)
norbert = Dragon.new('Norbert')
while true
  mname = gets.chomp

  if mnaem == "exit"
    exit
  elsif ["feed", "walk", "putToBed", "toss", "rock"].find{|s| s == mname}
    norbert.method(mname).call
  else
    puts "そんなメソッドは無い"
  end
end