Part (a)

Write the average method that calculates the arithmetic mean of scores between indices first and last (inclusive).

Solution

private double average(int first, int last)
{
    int sum = 0;
    int numScores = 0;
    
    for (int i = first; i <= last; i++)
    {
        sum += scores[i];
        numScores++;
    }
    
    return sum / (double) numScores;
}

Part (b)

Write the hasImproved method that returns true if each score is greater than or equal to the previous score.

Solution

private boolean hasImproved()
{
    for (int i = 1; i < scores.length; i++)
    {
        if (scores[i] < scores[i - 1])
            return false;
    }
    return true;
}

Part (c)

Write the finalAverage method that returns the average of all scores, or just the second half if the student improved.

Solution

public double finalAverage()
{
    int start = 0;
    
    if (hasImproved())
        start = scores.length / 2;
    
    return average(start, scores.length - 1);
}

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