public final void createCodeTable(Reader src) throws IOException {
        encodeTable = new HashMap<>();
        int c = src.read();
        while (c != -1) {
            countChar(c);
        }
        // Phase 1 - count character frequencies
        // phase 2 - build the huffman tree
        // assign codes to each character
        //print encode table, to enable checking of output
        for (int ch : encodeTable.keySet())
            System.out.println(encodeTable.get(c));
    }

   public void countChar(int c) {
        HuffmanNode value = encodeTable.get(c);
        if (value == null) {
            HuffmanNode node = new HuffmanNode(c);
            node.count++;
            encodeTable.put(c, node);
        }else {
            value.count++;
        }