mystery-methods.rb

def mystery1(n)
  puts n
  if n == 1
    return n
  else
    return n + mystery1(n-1)
  end
end

def mystery2(n)
  if n < 10
    return n
  else
    return (n%10) + mystery2(n/10)
  end
end

def mystery3(n)
  if n == 0
    return 100
  elsif n == -1
    return 200
  end
  if n%2 == 0
    return mystery3(n/2)
  else
    return mystery3(n-1)
  end
end

def mystery4(b,e)
  if e == 0
    return 1
  else
    return b * mystery4(b,e-1)
  end
end

def mystery5(s)
  if s.length == 0
    return ""
  else
    return "*" + mystery5(s[1..-1])
  end
end

def mystery6(s)
  if s == nil || s.length == 0
    return ""
  else
    space = 0
    until space >= s.length || s[space] == " "
      space += 1
    end
    return mystery6(s[(space+1)..-1]) + " " + s[0...space]
  end
end

def mystery7(word)
  if word.length < 2
    return true
  elsif word[0] != word[-1]
    return false
  else
    return mystery7(word[1..-2])
  end
end