DataSet.java import java.util.Arrays;
/**
This class computes the alternating sum
of a set of data values.
*/
public class DataSet
{
private double[] data;
private int dataSize;
/**
Constructs an empty data set.
*/
public DataSet()
{
final int DATA_LENGTH = 100;
data = new double[DATA_LENGTH];
dataSize = 0;
}
/**
Adds a data value to the data set.
@param x a data value
*/
public void add(double x)
{
if (dataSize == data.length)
data = Arrays.copyOf(data, 2 * data.length);
data[dataSize] = x;
dataSize++;
}
/**
Gets the alternating sum of the added data.
@return sum the sum of the alternating data or 0 if no data has been added
*/
public double alternatingSum()
{
. . .
}
}
Use the following file:
AlternatingSumTester.java
/**
This program calculates an alternating sum.
*/
public class AlternatingSumTester
{
public static void main(String[] args)
{
DataSet data = new DataSet();
data.add(1);
data.add(4);
data.add(9);
data.add(16);
data.add(9);
data.add(7);
data.add(4);
data.add(9);
data.add(11);
double sum = data.alternatingSum();
System.out.println("Alternating Sum: " + sum);
System.out.println("Expected: -2.0");
}
}