SOURCE CODE FILES FOR Average EXAMPLES

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/**
 * Project Average1
 * Class Main
 * 
 * Compute the average of integers entered
 * in an option dialog. The user enters the 
 * count of numbers to enter in advance.
 */

import javax.swing.JOptionPane;
public class Main
{
    public static void main(String[] args)
    {
        // number must be initialized to 0 because
        // the compiler cannot determine whether
        // the for loop executes at least once.
        int number = 0, count, sum = 0, i;
        double average;

        count = Integer.parseInt(
            (JOptionPane.showInputDialog(
                "Enter size of integer list.")));
        for(i = 1; i <= count; i++)
        {
            number = Integer.parseInt(
                JOptionPane.showInputDialog(
                    "Enter int #" + i + ":"));           
            sum += number;
        }
        
        // The expression  (double) sum
        // converts sum into a double.
        // (double) is called a "cast" operator.
        average = (double) sum / count;
        System.out.println("The average is " + average);
    }
}

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/**
 * Project Average2
 * Class Main
 * 
 * Compute the average of integers entered
 * in an option dialog.  Use Cancel as a sentinel
 * to terminate the list.  Note that 
 * JOptionPane.showInputDialog returns
 * a reference to null (no String object returned)
 * when Cancel is clicked in the input dialog.
 */

import javax.swing.JOptionPane;
public class Main
{
    public static void main(String[] args)
    {
        String inputString;
        int number, count = 0, sum = 0;
        double average;

        System.out.println("Enter a list of ints.");
        System.out.println("Click Cancel to terminate list.");
        inputString = JOptionPane.showInputDialog(
            "Enter an int.");
        while(inputString != null)
        {
            number = Integer.parseInt(inputString);
            sum += number;
            count++;
            inputString = JOptionPane.showInputDialog(
                "Enter an int.");
       }
        average = (double) sum / count;
        System.out.println("The average is " + average);
    }
}

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