Method isbn10CheckDigit

src/main/java/com/github/javafaker/Code.java:121–128

(CharSequence t)

    }

    private final int isbn10CheckDigit(CharSequence t) {
        String value = stripIsbnSeparator(t);
        int sum = 0;
        for (int i = 0; i < value.length(); i++) {
            sum += ((i + 1) * toInt(value.substring(i, i + 1)));
        }
        return sum % 11;
    }

    private final int isbn13CheckDigit(CharSequence t) {
        String value = stripIsbnSeparator(t);