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Question: Create a new Java file, containing this code public class DataStatsUser { public static void...

Create a new Java file, containing this code

public class DataStatsUser {
    public static void main (String[] args) { 
      DataStats d = new DataStats(6); 
      d.append(1.1);
      d.append(2.1);
      d.append(3.1);
      System.out.println("final so far is: " + d.mean()); d.append(4.1);
      d.append(5.1);
      d.append(6.1);
      System.out.println("final mean is: " + d.mean());
    } 
  }

This code depends on a class called DataStats, with the following API:

public class DataStats {
    public DataStats(int N) {
    }
       // set up an array (to accept up to N doubles) and other member variables
    public double mean() {
        return 0;
    }
       //compute and return the mean of the set of numbers added so far
    public void append(double in) {
    }
       //append number to the set; throw error if more than N numbers added
 }

Your job: implement DataStats, so that it correctly works when used by DataStatsUser.

Answer 1

//Java code

public class DataStats {
    private double data[];
    //Count number of elements in array
    private  int count;
    //Constructor
    public DataStats(int N) {
        //create array of given size N
        // set up an array (to accept up to N doubles) and other member variables
        data = new double[N];
        count =0;
    }

    //compute and return the mean of the set of numbers added so far
    public double mean() {
        double  sum=0.0;
        for (int i = 0; i < count; i++) {
            sum+=data[i];
        }
        double avg = sum/count;
        return avg;
    }

    /**
     * append number to the set; throw error if more than N numbers added
     * @param in
     */
    public void append(double in) {
        try {
            if(count>data.length)
                throw  new ArrayIndexOutOfBoundsException();
            data[count] = in;
            count++;
        }
        catch (ArrayIndexOutOfBoundsException e)
        {
            System.err.println("Array is full now.......");
        }

    }

}

//==============================================

public class DataStatsUser {
    public static void main (String[] args) {
        DataStats d = new DataStats(6);
        d.append(1.1);
        d.append(2.1);
        d.append(3.1);
        System.out.println("final so far is: " + d.mean()); d.append(4.1);
        d.append(5.1);
        d.append(6.1);

        System.out.println("final mean is: " + d.mean());
    }
}

//Output

//If you need any help regarding this solution .......... please leave a comment ......... thanks