Method calculateWpm

data/java/04_exceptions.java:8–13

(int words, int seconds)

class ExceptionsDemo {
    static double calculateWpm(int words, int seconds) throws InvalidDurationException {
        if (seconds <= 0) {
            throw new InvalidDurationException("seconds must be greater than 0");
        }
        return (words * 60.0) / seconds;
    }

    public static void main(String[] args) {
        try {