excel.rb

@chars = ("A".."Z").to_a

def increase_discharge(str, d)
  if str[-d] == @chars.last
    str[-d] = @chars.first
    increase_discharge(str, d+1)
  else
    if str[-d].nil?
      str.insert(0, @chars.first)
    else
      str[-d] = @chars[(@chars.find_index(str[-d])+1)]
    end
  end
  str
end


def generate_names(n)
  result = []
  current = "A"
  (n-1).times {
    current = increase_discharge(current, 1)
    puts current # => B,C,D,E
    result << current # => E,E,E,E ????????
  }
  result
end


puts generate_names(100)