private static BigDecimal processCoinEntry(int[] coin_totals, BigDecimal balance, Coin inserted_coin) {

        // convert value to String
        String insert_Coin_str = inserted_coin.getValue().toString();

        switch (insert_Coin_str) {
            case "1":
                addCoinToCategoryTotal(coin_totals, 0);
                balance = addInsertedCoinToBalance(inserted_coin.getValue(), balance);

                break;
            case "0.5":
                addCoinToCategoryTotal(coin_totals, 1);
                balance = addInsertedCoinToBalance(inserted_coin.getValue(), balance);

                break;
            case "0.2":
                addCoinToCategoryTotal(coin_totals, 2);
                balance = addInsertedCoinToBalance(inserted_coin.getValue(), balance);

                break;
            case "0.1":
                addCoinToCategoryTotal(coin_totals, 3);
                balance = addInsertedCoinToBalance(inserted_coin.getValue(), balance);

                break;
        }

        return balance;
    }