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Provided Code

public class Review
{
    private int rating;
    private String comment;
        public Review(int r, String c) {
        rating = r; comment = c;
    }
        public int getRating() {
        return rating;
    }
        public String getComment() {
        return comment;
    }
}

public class ReviewAnalysis
{
    private Review[] allReviews;  // array, not ArrayList
    public ReviewAnalysis() { /* not shown */ }
    public double getAverageRating() { /* to be implemented in part (a) */ }
    public ArrayList collectComments() { /* to be implemented in part (b) */ }
}

Part A — 4 Points

Write getAverageRating, which returns the average rating of all elements in allReviews as a double.

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public double getAverageRating()
{
    double sum = 0;
    for (Review r : allReviews)
    {
        sum += r.getRating();
    }
    return sum / allReviews.length;
}

Part B — 5 Points

Write collectComments, which returns an ArrayList of formatted comments that contain "!". Each string is formatted as index + "-" + comment. If comment doesn’t end in . or !, append a period.

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public ArrayList collectComments()
{
    ArrayList result = new ArrayList();
    for (int i = 0; i < allReviews.length; i++)
    {
        String comment = allReviews[i].getComment();
        if (comment.contains("!"))
        {
            String formatted = i + "-" + comment;
            char last = comment.charAt(comment.length() - 1);
            if (last != '.' && last != '!')
            {
                formatted += ".";
            }
            result.add(formatted);
        }
    }
    return result;
}

Common Mistakes to Avoid

for (Review r : allReviews) {
    // no way to get the index 'i' here
}

for (int i = 0; i < allReviews.length; i++) {
    String comment = allReviews[i].getComment();
    if (comment.contains("!")) {
        String formatted = i + "-" + comment;
        ...
    }
}

int sum = 0;
...
return sum / allReviews.length;  // truncates decimal!

double sum = 0;  // or cast: (double) sum / allReviews.length
...
return sum / allReviews.length;

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