SOURCE CODE FILES FOR INTRO EXAMPLES

==============================================================================

/**
 * Project Greeter1
 * Class Main
 * 
 * The traditional Hello World program that
 * displays the message "Hello, World."
 * No objects are created because the main
 * method is static.
 * 
 * @Steve Jost 
 * @6/9/02
 */
public class Main
{
    /**
    * The main method, which is the entry point
    * for the application.
    */
    public static void main(String args[])
    {
        System.out.println("Hello, World.");
    }
}

==============================================================================

/**
 * Project Greeter2
 * Class Main
 * 
 * The application inputs a name using an
 * input dialog, then prints a greeting for
 * that person.
 * 
 * @Steve Jost 
 * @8/25/02
 */

import javax.swing.JOptionPane;

public class Main
{
    /**
    * The main method, which is the entry point
    * for the application.
    */
    public static void main(String args[])
    {
        String name;

        name = JOptionPane.showInputDialog("Enter your name.");
        System.out.println("Hello, " + name + ".");
    }
}

// Input in input dialog:
Steve
// Output:
Hello, Steve.

==============================================================================

/**
 * Project VendingMachine
 * Project Main
 * 
 * Test the VendingMachine class methods.
 */
public class Main
{
    public static void main(String[] args)
    {
        VendingMachine vm;
        
        // Create new VendingMachine object with
        // 3 candy bars.
        vm = new VendingMachine(3);
        
        // Print status of VendingMachine object.
        vm.printStatus();
        
        // Deposit 3 quarters (correct amount) and 
        // select candy.  Then print status of vending 
        // machine.
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.selectCandy();
        vm.printStatus();
        
        // Deposit 5 quarters (too many) and select
        // candy.  Then print the status.
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.selectCandy();
        vm.printStatus();
        
        // Deposit 2 quarters (too few) and select
        // candy.  Then print the status.
        vm.depositQuarter();
        vm.depositQuarter();
        vm.selectCandy();
        vm.printStatus();
        
        // Deposit 3 quarters (correct amount) and 
        // select candy.  Then print the status.
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.selectCandy();
        vm.printStatus();        
        
        // Deposit 3 quarters (correct amount) and 
        // select candy.  Then print the status.
        vm.depositQuarter();
        vm.depositQuarter();
        vm.depositQuarter();
        vm.selectCandy();
        vm.printStatus();        
    }
}
// Output in Terminal Window:
Number of candy bars = 3
Number of quarters = 0

Candy bar dispensed.
Number of candy bars = 2
Number of quarters = 0

Candy bar dispensed.
Number of candy bars = 1
Number of quarters = 0

Could not dispense candy bar
Number of candy bars = 1
Number of quarters = 2

Candy bar dispensed.
Number of candy bars = 0
Number of quarters = 0

Could not dispense candy bar
Number of candy bars = 0
Number of quarters = 3

------------------------------------------------------------------------------

/**
 * Project VendingMachine
 * Class VendingMachine
 * 
 * The VendingMachine is a variation of the class
 * Vending1 in Chapter 2 of the textbook.
 * 
 * Assumptions:
 * (1) The vending machine only dispenses candy bars.
 * (2) Candy costs $0.75 (3 quarters).
 * (3) You use the depositQuarter method to enter quarters.
 * (4) After entering 3 quarters, use the selectCandy
 *     method to get the candy bar.
 * (5) If you enter too many quarters, you do not get
 *     change back.
 * (6) If the vending machine is out of candy bars,
 *     you do not get your money back.
 */

public class VendingMachine
{
    // Instance Variables:
    // The number of candy bars currently in machine.    
    public int numberCandyBars;

    // The number of quarters deposited for current
    // candy bar purchase.
    public int numberQuarters;
    
    // Default NoArg Constructor
    public VendingMachine()
    {
        numberCandyBars = 0;
        numberQuarters = 0;
    }
    
    public VendingMachine(int n)
    {
        numberCandyBars = n;
        numberQuarters = 0;
    }
    
    public void depositQuarter()
    {
        numberQuarters++;
    }
    
    public void selectCandy()
    {
        if(numberQuarters >= 3 && numberCandyBars > 0)
        {
            System.out.println("Candy bar dispensed.");
            numberQuarters = 0;
            numberCandyBars--;
        }
        else
        {
            System.out.println(
                "Could not dispense candy bar");
        }
    }
    
    public void printStatus()
    {
        System.out.println(
            "Number of candy bars = " + numberCandyBars);
        System.out.println(
            "Number of quarters = " + numberQuarters);
        System.out.println();
    }
}

==============================================================================


/**
 * Project CoinFlipper
 * Class Main
 * 
 * Simulate random flips of a coin and record
 * the results.
 * 
 * @Steve Jost
 * @6/10/02
 */
public class Main
{
    public static void main(String[] args)
    {
        // Create the Coin object.
        Coin x = new Coin();
    
        // Alternate between printing current face
        // and flipping the coin to get a new face.
        System.out.println("Flip #1: " + x);
        x.flip();
        System.out.println("Flip #2: " + x);
        x.flip();
        System.out.println("Flip #3: " + x);
        x.flip();
        System.out.println("Flip #4: " + x);
        x.flip();
        System.out.println("Flip #5: " + x);
    }
}

------------------------------------------------------------------------------

/**
 * Project CoinFlipper
 * Class Coin
 *
 * The Coin class keeps track of the face that
 * is showing ("Head" or "Tail").  It also provides
 * a flip method for randomly changing the face.
 * 
 * @Steve Jost
 * @6/9/02
 */
public class Coin
{
    // Keeps track of the face that is showing.
    private String face;

    /**
     * Constructor for objects of class Coin
     */
    public Coin()
    {
        // Randomly set the initial value of face.
        flip();
    }

    /**
     * The flip method randomly sets the currently
     * showing face using the library method random.
     */
    public void flip()
    {
        if (Math.random() < 0.5)
            face = "Tail";
        else 
            face = "Head";
    }
    
     /**
     * Return the currently showing face when
     * the object is printed.
     */
    public String toString()
    {
        return face;
    }
}

==============================================================================

/**
 * Project TempConverter
 * Class Main
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Main
{
    public static void main(String[] args)
    {
        TempConverter x = new TempConverter();
    }
}

------------------------------------------------------------------------------

/**
 * Project TempConverter
 * Class TempConverter
 * 
 * @Steve Jost 
 * @6/10/02
 */

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
    
public class TempConverter extends JFrame
{
    // Declare instance variables.
    private JPanel panel;
    private JTextField cel, fahr;
    private JLabel celLabel, fahrLabel;
    private JButton button;

    /**
     * Constructor of TempConverter class.
     */
    public TempConverter()
    {
        // Create control objects.
        panel = new JPanel();
        cel = new JTextField(8);
        fahr = new JTextField(8);
        celLabel = new JLabel("Celsius");
        fahrLabel = new JLabel("Fahrenheit");
        button = new JButton("Convert");
        
        // Add controls to panel.
        panel.add(cel);
        panel.add(celLabel);
        panel.add(fahr);
        panel.add(fahrLabel);
        panel.add(button);
        
        // Set panel as the content pane.
        setContentPane(panel);
        
        // Add an ActionListener object to the
        // button.
        MyActionListener al = new MyActionListener();
        button.addActionListener(al);
        
        // Set size of the application window.
        setSize(120, 180);
        
        // Make the window visible.
        show();
    }
    
    // Inner class that implements the ActionListener
    // object.  Any ActionListener object must implement
    // an actionPerformed method.
    private class MyActionListener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            int c, f;
            
            c = Integer.parseInt(cel.getText());
            f = 9 * c / 5 + 32;
            fahr.setText(String.valueOf(f));
        }
    }
}

==============================================================================