Hey everyone, I have no experience with writing programs. This is my first program and I'm sort of "winging it". I have a problem converting from fahrenheit to celsius, I can convert from celsius to fahrenheit fine though. The bolded part is where I'm having troubles. Here is what I've got:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * TemperatureConverterGUI.java
 *
 * Created on Jan 28, 2010, 9:24:37 PM
 */

package learn;

/**
 *
 * @author Matt
 */
public class TemperatureConverterGUI extends javax.swing.JFrame {

    /** Creates new form TemperatureConverterGUI */
    public TemperatureConverterGUI() {
        initComponents();
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        celsiusTempTextField = new javax.swing.JTextField();
        celsiusLabel = new javax.swing.JLabel();
        convertButton1 = new javax.swing.JButton();
        fahrenheitLabel = new javax.swing.JLabel();
        fahrenheitTempTextField = new javax.swing.JTextField();
        fahrenheitLabel2 = new javax.swing.JLabel();
        celsiusLabel2 = new javax.swing.JLabel();
        convertButton2 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Temperature Converter");

        celsiusLabel.setText("Celsius");

        convertButton1.setText("Convert");
        convertButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                convertButton1ActionPerformed(evt);
            }
        });

        fahrenheitLabel.setText("Fahrenheit");

        fahrenheitLabel2.setText("Fahrenheit");

        celsiusLabel2.setText("Celsius");

        convertButton2.setText("Convert");
        convertButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                convertButton2ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(celsiusTempTextField, javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(convertButton1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addGap(26, 26, 26)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                    .addComponent(celsiusLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(fahrenheitLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addGap(77, 77, 77)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(convertButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(fahrenheitTempTextField, javax.swing.GroupLayout.DEFAULT_SIZE, 71, Short.MAX_VALUE))
                .addGap(30, 30, 30)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                    .addComponent(celsiusLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(fahrenheitLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap(110, Short.MAX_VALUE))
        );

        layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {celsiusTempTextField, convertButton1, convertButton2, fahrenheitTempTextField});

        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(celsiusTempTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(celsiusLabel)
                    .addComponent(fahrenheitTempTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(fahrenheitLabel2))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(convertButton1)
                    .addComponent(fahrenheitLabel)
                    .addComponent(celsiusLabel2)
                    .addComponent(convertButton2))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        layout.linkSize(javax.swing.SwingConstants.VERTICAL, new java.awt.Component[] {celsiusTempTextField, convertButton1, convertButton2, fahrenheitTempTextField});

        pack();
    }// </editor-fold>                        

    private void convertButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                               
   //Parse degrees Celsius as a double and convert to Fahrenheit.
    int tempFahr = (int)((Double.parseDouble(celsiusTempTextField.getText()))
            * 1.8 + 32);
    fahrenheitLabel.setText(tempFahr + " Fahrenheit");
     // TODO add your handling code here:
    }                                              

    private void convertButton2ActionPerformed(java.awt.event.ActionEvent evt) [B]{                                               
 //Parse degrees Fahrenheit as a double and convert to Celsius.
    int tempCels = (int) (fahrenheitTempTextField.getText())
        ((5.0 / 9) * (fahrenheitTempTextField - 32));
    celsiusLabel2.setText(tempCels + " Celsius");
       // TODO add your handling code here:
    }                                              [/B]

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TemperatureConverterGUI().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel celsiusLabel;
    private javax.swing.JLabel celsiusLabel2;
    private javax.swing.JTextField celsiusTempTextField;
    private javax.swing.JButton convertButton1;
    private javax.swing.JButton convertButton2;
    private javax.swing.JLabel fahrenheitLabel;
    private javax.swing.JLabel fahrenheitLabel2;
    private javax.swing.JTextField fahrenheitTempTextField;
    // End of variables declaration                   

}

The bolded is where I'm having problems. What would I have to do to fix this problem? Thanks for all the help!

Edited 3 Years Ago by Nick Evan: Fixed formatting

Please use code tags!

The formula for a conversion to Celcius would be

C = (F - 32) / 1.8

So the boiling point of water would be (212 - 32) / 1.8, which would evaluate to 100. Incorporate that into your code.

try:

-get value of the text field
-save it to a String
-convert that string to int

Also change the variable type to double because of the
division (.. / 1.8 )

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * TemperatureConverterGUI.java
 *
 * Created on Jan 28, 2010, 9:24:37 PM
 */

/**
 * 
 * @author Matt
 */
public class TemperatureConverterGUI extends javax.swing.JFrame {

	/** Creates new form TemperatureConverterGUI */
	public TemperatureConverterGUI() {
		initComponents();
	}

	/**
	 * This method is called from within the constructor to initialize the form.
	 * WARNING: Do NOT modify this code. The content of this method is always
	 * regenerated by the Form Editor.
	 */
	@SuppressWarnings("unchecked")
	// <editor-fold defaultstate="collapsed" desc="Generated Code">
	private void initComponents() {

		celsiusTempTextField = new javax.swing.JTextField();
		celsiusLabel = new javax.swing.JLabel();
		convertButton1 = new javax.swing.JButton();
		fahrenheitLabel = new javax.swing.JLabel();
		fahrenheitTempTextField = new javax.swing.JTextField();
		fahrenheitLabel2 = new javax.swing.JLabel();
		celsiusLabel2 = new javax.swing.JLabel();
		convertButton2 = new javax.swing.JButton();

		setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
		setTitle("Temperature Converter");

		celsiusLabel.setText("Celsius");

		convertButton1.setText("Convert");
		convertButton1.addActionListener(new java.awt.event.ActionListener() {
			public void actionPerformed(java.awt.event.ActionEvent evt) {
				convertButton1ActionPerformed(evt);
			}
		});

		fahrenheitLabel.setText("Fahrenheit");

		fahrenheitLabel2.setText("Fahrenheit");

		celsiusLabel2.setText("Celsius");

		convertButton2.setText("Convert");
		convertButton2.addActionListener(new java.awt.event.ActionListener() {
			public void actionPerformed(java.awt.event.ActionEvent evt) {
				convertButton2ActionPerformed(evt);
			}
		});

		javax.swing.GroupLayout layout = new javax.swing.GroupLayout(
				getContentPane());
		getContentPane().setLayout(layout);
		layout
				.setHorizontalGroup(layout
						.createParallelGroup(
								javax.swing.GroupLayout.Alignment.LEADING)
						.addGroup(
								layout
										.createSequentialGroup()
										.addContainerGap()
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.LEADING,
																false)
														.addComponent(
																celsiusTempTextField,
																javax.swing.GroupLayout.Alignment.TRAILING)
														.addComponent(
																convertButton1,
																javax.swing.GroupLayout.Alignment.TRAILING,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE))
										.addGap(26, 26, 26)
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.TRAILING,
																false)
														.addComponent(
																celsiusLabel,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE)
														.addComponent(
																fahrenheitLabel,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE))
										.addGap(77, 77, 77)
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.LEADING,
																false)
														.addComponent(
																convertButton2,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE)
														.addComponent(
																fahrenheitTempTextField,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																71,
																Short.MAX_VALUE))
										.addGap(30, 30, 30)
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.TRAILING,
																false)
														.addComponent(
																celsiusLabel2,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE)
														.addComponent(
																fahrenheitLabel2,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																Short.MAX_VALUE))
										.addContainerGap(110, Short.MAX_VALUE)));

		layout
				.linkSize(javax.swing.SwingConstants.HORIZONTAL,
						new java.awt.Component[] { celsiusTempTextField,
								convertButton1, convertButton2,
								fahrenheitTempTextField });

		layout
				.setVerticalGroup(layout
						.createParallelGroup(
								javax.swing.GroupLayout.Alignment.LEADING)
						.addGroup(
								layout
										.createSequentialGroup()
										.addContainerGap()
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.BASELINE)
														.addComponent(
																celsiusTempTextField,
																javax.swing.GroupLayout.PREFERRED_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.PREFERRED_SIZE)
														.addComponent(
																celsiusLabel)
														.addComponent(
																fahrenheitTempTextField,
																javax.swing.GroupLayout.PREFERRED_SIZE,
																javax.swing.GroupLayout.DEFAULT_SIZE,
																javax.swing.GroupLayout.PREFERRED_SIZE)
														.addComponent(
																fahrenheitLabel2))
										.addPreferredGap(
												javax.swing.LayoutStyle.ComponentPlacement.RELATED)
										.addGroup(
												layout
														.createParallelGroup(
																javax.swing.GroupLayout.Alignment.BASELINE)
														.addComponent(
																convertButton1)
														.addComponent(
																fahrenheitLabel)
														.addComponent(
																celsiusLabel2)
														.addComponent(
																convertButton2))
										.addContainerGap(
												javax.swing.GroupLayout.DEFAULT_SIZE,
												Short.MAX_VALUE)));

		layout
				.linkSize(javax.swing.SwingConstants.VERTICAL,
						new java.awt.Component[] { celsiusTempTextField,
								convertButton1, convertButton2,
								fahrenheitTempTextField });

		pack();
	}// </editor-fold>

	private void convertButton1ActionPerformed(java.awt.event.ActionEvent evt) {
		// Parse degrees Celsius as a double and convert to Fahrenheit.
		int tempFahr = (int) ((Double.parseDouble(celsiusTempTextField
				.getText())) * 1.8 + 32);
		fahrenheitLabel.setText(tempFahr + " Fahrenheit");
		// TODO add your handling code here:
	}

	private void convertButton2ActionPerformed(java.awt.event.ActionEvent evt) {
		// Parse degrees Fahrenheit as a double and convert to Celsius.

		// C = (F - 32) / 1.8
		String stringFahrenheit = fahrenheitTempTextField.getText();
		int fahrenheit = Integer.parseInt(stringFahrenheit);
		double tempCels = (fahrenheit - 32) / 1.8;
		celsiusLabel2.setText(tempCels + " Celsius");
		// TODO add your handling code here:
	}

	/**
	 * @param args
	 *            the command line arguments
	 */
	public static void main(String args[]) {
		java.awt.EventQueue.invokeLater(new Runnable() {
			public void run() {
				new TemperatureConverterGUI().setVisible(true);
			}
		});
	}

	// Variables declaration - do not modify
	private javax.swing.JLabel celsiusLabel;
	private javax.swing.JLabel celsiusLabel2;
	private javax.swing.JTextField celsiusTempTextField;
	private javax.swing.JButton convertButton1;
	private javax.swing.JButton convertButton2;
	private javax.swing.JLabel fahrenheitLabel;
	private javax.swing.JLabel fahrenheitLabel2;
	private javax.swing.JTextField fahrenheitTempTextField;
	// End of variables declaration

}
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