Programming Forums > Application Development > Java

ReggaetonKing · Feb 22nd, 2006, 10:01 PM

[PHP]
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Converter extends JApplet implements ActionListener
{
double celsius, fahrenheit;
String input;
JTextField input1, input2, output;
public void init()
{
super.setSize(450, 200);
Container panel = getContentPane();
panel.setLayout(new FlowLayout());
panel.add(new JLabel("Enter Celsius: "));
input1 = new JTextField(10);
input1.addActionListener(this);
panel.add(input1); // adds celsius field
panel.add(new JLabel("Enter Fahrenheit: "));
input2 = new JTextField(10);
input2.addActionListener(this);
panel.add(input2); // adds fahrenheit field
output = new JTextField(10);
output.setEditable(false);
panel.add(new JLabel("Convert Temperture: "));
panel.add(output);

}
public void actionPerformed(ActionEvent actionEvent)
{

if (actionEvent.getSource() == input2) //returns weird numbers!
{
input1.setText("");
double fahr = Double.parseDouble(input2.getText());
double newCel = convertToCelsius(fahr);
output.setText(newCel + " Celsius");
}
else if (actionEvent.getSource() == input1) //works
{
input2.setText("");
double cel = Double.parseDouble(input1.getText());
double newFahr = convertToFahrenheit(cel);
output.setText(newFahr + " Fahrenheit");
}
}
public static double convertToCelsius(double d)
{
return (5.0 / 9.0) * (d - 32);
}
public static double convertToFahrenheit(double c)
{
return 9.0 / 5.0 * c + 32;
}
}
[/PHP]

when I type a number in the Fahrenheit field, the results comes up weird
example: I type 1 and the result is like 222222222 Celsius.

wtf is wrong with this. I have been working on it for like 1 hours debugging trying all different possibilities! but idk, someone out there help me!

oNe8 · Feb 22nd, 2006, 10:16 PM

(Toggle Plain Text)

    public static double convertToFahrenheit(double c)
    {
        return (9.0 / 5.0) * c + 32;
    }

Order of opertaions mix up

jaeusm · Feb 22nd, 2006, 10:58 PM

Quote:

when I type a number in the Fahrenheit field, the results comes up weird
example: I type 1 and the result is like 222222222 Celsius.

Your code looks correct, and the answer should be -17.2222222222...
I don't do much GUI programming in Java, but maybe the -17 is being pushed out of the viewable area. Maybe you could try reducing the number of decimal places.

titaniumdecoy · Feb 22nd, 2006, 11:22 PM

You can use the NumberFormat class to format floating-point decimals; here is an example:

(Toggle Plain Text)

import java.text.NumberFormat;
public class NumberFormatTest {
	public static void main(String[] args) {
		NumberFormat nf = java.text.NumberFormat.getInstance();
		nf.setGroupingUsed(true); // add commas
		nf.setMaximumFractionDigits(3); // max digits after decimal point
		String formattedNumStr = nf.format( -17.2222222222D );
		System.out.println(formattedNumStr); // will print -17.222
	}
}

Here are some more examples that I found useful. (Warning: Java Applet)

ReggaetonKing · Feb 23rd, 2006, 7:01 AM

omg! why didnt I think of that! Thanks you guys, that must be the problem! I'll inform anyone when I try to use the NumberFormat

Feb 22nd, 2006, 10:01 PM	#1
ReggaetonKing Sexy Programmer Join Date: Nov 2005 Location: New Jersey Posts: 891 Rep Power: 3	Converter, my first multiple action listener program [PHP] import javax.swing.; import java.awt.; import java.awt.event.; public class Converter extends JApplet implements ActionListener { double celsius, fahrenheit; String input; JTextField input1, input2, output; public void init() { super.setSize(450, 200); Container panel = getContentPane(); panel.setLayout(new FlowLayout()); panel.add(new JLabel("Enter Celsius: ")); input1 = new JTextField(10); input1.addActionListener(this); panel.add(input1); // adds celsius field panel.add(new JLabel("Enter Fahrenheit: ")); input2 = new JTextField(10); input2.addActionListener(this); panel.add(input2); // adds fahrenheit field output = new JTextField(10); output.setEditable(false); panel.add(new JLabel("Convert Temperture: ")); panel.add(output); } public void actionPerformed(ActionEvent actionEvent) { if (actionEvent.getSource() == input2) //returns weird numbers! { input1.setText(""); double fahr = Double.parseDouble(input2.getText()); double newCel = convertToCelsius(fahr); output.setText(newCel + " Celsius"); } else if (actionEvent.getSource() == input1) //works { input2.setText(""); double cel = Double.parseDouble(input1.getText()); double newFahr = convertToFahrenheit(cel); output.setText(newFahr + " Fahrenheit"); } } public static double convertToCelsius(double d) { return (5.0 / 9.0) (d - 32); } public static double convertToFahrenheit(double c) { return 9.0 / 5.0 * c + 32; } } [/PHP] when I type a number in the Fahrenheit field, the results comes up weird example: I type 1 and the result is like 222222222 Celsius. wtf is wrong with this. I have been working on it for like 1 hours debugging trying all different possibilities! but idk, someone out there help me! __________________ I would love to change the world, but they won't give me the source code!

Feb 22nd, 2006, 10:16 PM	#2
oNe8 Newbie Join Date: Jan 2006 Posts: 17 Rep Power: 0	(Toggle Plain Text) public static double convertToFahrenheit(double c) { return (9.0 / 5.0) * c + 32; } public static double convertToFahrenheit(double c) { return (9.0 / 5.0) * c + 32; } Order of opertaions mix up __________________ http://img523.imageshack.us/img523/8436/user9kz.jpg

Feb 22nd, 2006, 11:22 PM	#4
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 843 Rep Power: 3	You can use the NumberFormat class to format floating-point decimals; here is an example: (Toggle Plain Text) import java.text.NumberFormat; public class NumberFormatTest { public static void main(String[] args) { NumberFormat nf = java.text.NumberFormat.getInstance(); nf.setGroupingUsed(true); // add commas nf.setMaximumFractionDigits(3); // max digits after decimal point String formattedNumStr = nf.format( -17.2222222222D ); System.out.println(formattedNumStr); // will print -17.222 } } import java.text.NumberFormat; public class NumberFormatTest { public static void main(String[] args) { NumberFormat nf = java.text.NumberFormat.getInstance(); nf.setGroupingUsed(true); // add commas nf.setMaximumFractionDigits(3); // max digits after decimal point String formattedNumStr = nf.format( -17.2222222222D ); System.out.println(formattedNumStr); // will print -17.222 } } Here are some more examples that I found useful. (Warning: Java Applet)

Feb 23rd, 2006, 7:01 AM	#5
ReggaetonKing Sexy Programmer Join Date: Nov 2005 Location: New Jersey Posts: 891 Rep Power: 3	omg! why didnt I think of that! Thanks you guys, that must be the problem! I'll inform anyone when I try to use the NumberFormat __________________ I would love to change the world, but they won't give me the source code!

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Programming Forums > Application Development > Java

Converter, my first multiple action listener program