class
  APPLICATION

create
  make

feature {NONE} -- Initialization

  make
      -- Read from the file and print frequencies.
    local
      file: PLAIN_TEXT_FILE
    do
      create file.make_open_read("input.txt")
      file.read_stream(file.count)
      file.close
      across get_frequencies(file.last_string) as f loop
        print(f.key.out + ": " + f.item.out + "%N")
      end
    end

feature -- Access

  get_frequencies (s: STRING): HASH_TABLE[INTEGER, CHARACTER]
      -- Hash table of counts for alphabetic characters in `s'.
    local
      char: CHARACTER
    do
      create Result.make(0)
      across s.area as st loop
        char := st.item
        if char.is_alpha then
          if Result.has(char) then
            Result.force(Result.at(char) + 1, char)
          else
            Result.put (1, char)
          end
        end
      end
    end
end