Programming Forums > Application Development > Java

Hadrurus · Aug 15th, 2005, 10:18 AM

I wonder if I could find any help with a problem I have regarding my latest program...

Im trying to generate a number at random between 200 & 400 and also display the average everytime a button is clicked, so the average will rise and fall but in theory eventually converge on or around 300.

So far my program only generates a number between 0 & 400 (not 200 & 400 as I need it to) and I havent any ideas for how to show an average after every click

Any help please?

(Toggle Plain Text)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

public class RandomNumber extends JFrame implements ActionListener {

    private JButton button;
    private JTextField valuesTextField, resultTextField;
    private Random random;

    public static void main(String[] args) {
        RandomNumber frame = new RandomNumber();
        frame.setSize(200,150);
        frame.createGUI();
        frame.show();
    }

    private void createGUI() {
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        Container window = getContentPane();
        window.setLayout(new FlowLayout());

        button = new JButton("Generate");
        window.add(button);
        button.addActionListener(this);

        valuesTextField = new JTextField(14);
        window.add(valuesTextField);

        random = new Random();
    }

    public void actionPerformed(ActionEvent event) {
     
    
        int one; 

        one = random.nextInt(400) + 1; 
        
        
        valuesTextField.setText("Number: "
            + Integer.toString(one));  }

}

Ooble · Aug 15th, 2005, 10:26 AM

Well, you're asking it for a number between a number between 1 and 400, so that's what it's going to give you. To get a number between a and b, you'll want to do this:

(Toggle Plain Text)

random_number = random.nextInt(b - a) + a + 1;

See if you can figure out why that's the case.

skuinders · Aug 15th, 2005, 10:27 AM

Use this for the random number:

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one = 200 + random.nextInt(200);

skuinders · Aug 15th, 2005, 10:37 AM

Here's a simple implementation of what you want:

(Toggle Plain Text)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

public class RandomNumber extends JFrame implements ActionListener {

	private JButton button;
	private JTextField valuesTextField, resultTextField, meanTextField;
	private Random random;
	private int total = 0;
	private int count = 0;
	
	public static void main(String[] args) {
		RandomNumber frame = new RandomNumber();
		frame.setSize(200,150);
		frame.createGUI();
		frame.show();
	}

	private void createGUI() {
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		Container window = getContentPane();
		window.setLayout(new FlowLayout());

		button = new JButton("Generate");
		window.add(button);
		button.addActionListener(this);

		valuesTextField = new JTextField(14);
		window.add(valuesTextField);

		meanTextField = new JTextField(14);
		window.add(meanTextField);

		random = new Random();
	}

	public void actionPerformed(ActionEvent event) {
		int r;
		count+=1;
		r = 200 + random.nextInt(200); 
		total+=r;
		valuesTextField.setText("Number: " + Integer.toString(r));  
		meanTextField.setText("Mean: " + Double.toString((double)total/count));  
	}
}

You just have to add variables that will keep track of the total and count and add a text box to display the mean.

Hadrurus · Aug 15th, 2005, 10:38 AM

Thanks Ooble and Skuinders both your help much appreciated

The program works perfectly now.

thanks again,

Navid · Aug 15th, 2005, 12:50 PM

Speaking of a random number, how would you get a random number in C? I'm curious about manipulating the range of the random number too.

skuinders · Aug 15th, 2005, 1:08 PM

http://cplus.about.com/od/cprogrammi.../aa041403c.htm

Aug 15th, 2005, 10:18 AM	#1
Hadrurus Newbie Join Date: Aug 2005 Location: Northampton, England Posts: 8 Rep Power: 0	Random Number & Average Problem I wonder if I could find any help with a problem I have regarding my latest program... Im trying to generate a number at random between 200 & 400 and also display the average everytime a button is clicked, so the average will rise and fall but in theory eventually converge on or around 300. So far my program only generates a number between 0 & 400 (not 200 & 400 as I need it to) and I havent any ideas for how to show an average after every click Any help please? (Toggle Plain Text) import java.awt.; import java.awt.event.; import javax.swing.; import java.util.; public class RandomNumber extends JFrame implements ActionListener { private JButton button; private JTextField valuesTextField, resultTextField; private Random random; public static void main(String[] args) { RandomNumber frame = new RandomNumber(); frame.setSize(200,150); frame.createGUI(); frame.show(); } private void createGUI() { setDefaultCloseOperation(EXIT_ON_CLOSE); Container window = getContentPane(); window.setLayout(new FlowLayout()); button = new JButton("Generate"); window.add(button); button.addActionListener(this); valuesTextField = new JTextField(14); window.add(valuesTextField); random = new Random(); } public void actionPerformed(ActionEvent event) { int one; one = random.nextInt(400) + 1; valuesTextField.setText("Number: " + Integer.toString(one)); } } import java.awt.; import java.awt.event.; import javax.swing.; import java.util.; public class RandomNumber extends JFrame implements ActionListener { private JButton button; private JTextField valuesTextField, resultTextField; private Random random; public static void main(String[] args) { RandomNumber frame = new RandomNumber(); frame.setSize(200,150); frame.createGUI(); frame.show(); } private void createGUI() { setDefaultCloseOperation(EXIT_ON_CLOSE); Container window = getContentPane(); window.setLayout(new FlowLayout()); button = new JButton("Generate"); window.add(button); button.addActionListener(this); valuesTextField = new JTextField(14); window.add(valuesTextField); random = new Random(); } public void actionPerformed(ActionEvent event) { int one; one = random.nextInt(400) + 1; valuesTextField.setText("Number: " + Integer.toString(one)); } } __________________ -Hadrurus Even if the voices aren't real, they have some good ideas.

Aug 15th, 2005, 10:26 AM	#2
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 8	Well, you're asking it for a number between a number between 1 and 400, so that's what it's going to give you. To get a number between a and b, you'll want to do this: (Toggle Plain Text) random_number = random.nextInt(b - a) + a + 1; random_number = random.nextInt(b - a) + a + 1; See if you can figure out why that's the case. __________________ Me :: You :: Them

Aug 15th, 2005, 10:27 AM	#3
skuinders Hobbyist Programmer Join Date: Jun 2005 Location: MA, US Posts: 204 Rep Power: 4	Use this for the random number: (Toggle Plain Text) one = 200 + random.nextInt(200); one = 200 + random.nextInt(200); __________________ "A stupid man's report of what a clever man says can never be accurate, because he unconciously translates what he hears into something he can understand." - B. Russell http://web.bryant.edu/~srk2 Last edited by skuinders; Aug 15th, 2005 at 10:38 AM.

Aug 15th, 2005, 10:37 AM	#4
skuinders Hobbyist Programmer Join Date: Jun 2005 Location: MA, US Posts: 204 Rep Power: 4	Here's a simple implementation of what you want: (Toggle Plain Text) import java.awt.; import java.awt.event.; import javax.swing.; import java.util.; public class RandomNumber extends JFrame implements ActionListener { private JButton button; private JTextField valuesTextField, resultTextField, meanTextField; private Random random; private int total = 0; private int count = 0; public static void main(String[] args) { RandomNumber frame = new RandomNumber(); frame.setSize(200,150); frame.createGUI(); frame.show(); } private void createGUI() { setDefaultCloseOperation(EXIT_ON_CLOSE); Container window = getContentPane(); window.setLayout(new FlowLayout()); button = new JButton("Generate"); window.add(button); button.addActionListener(this); valuesTextField = new JTextField(14); window.add(valuesTextField); meanTextField = new JTextField(14); window.add(meanTextField); random = new Random(); } public void actionPerformed(ActionEvent event) { int r; count+=1; r = 200 + random.nextInt(200); total+=r; valuesTextField.setText("Number: " + Integer.toString(r)); meanTextField.setText("Mean: " + Double.toString((double)total/count)); } } import java.awt.; import java.awt.event.; import javax.swing.; import java.util.; public class RandomNumber extends JFrame implements ActionListener { private JButton button; private JTextField valuesTextField, resultTextField, meanTextField; private Random random; private int total = 0; private int count = 0; public static void main(String[] args) { RandomNumber frame = new RandomNumber(); frame.setSize(200,150); frame.createGUI(); frame.show(); } private void createGUI() { setDefaultCloseOperation(EXIT_ON_CLOSE); Container window = getContentPane(); window.setLayout(new FlowLayout()); button = new JButton("Generate"); window.add(button); button.addActionListener(this); valuesTextField = new JTextField(14); window.add(valuesTextField); meanTextField = new JTextField(14); window.add(meanTextField); random = new Random(); } public void actionPerformed(ActionEvent event) { int r; count+=1; r = 200 + random.nextInt(200); total+=r; valuesTextField.setText("Number: " + Integer.toString(r)); meanTextField.setText("Mean: " + Double.toString((double)total/count)); } } You just have to add variables that will keep track of the total and count and add a text box to display the mean. __________________ "A stupid man's report of what a clever man says can never be accurate, because he unconciously translates what he hears into something he can understand." - B. Russell http://web.bryant.edu/~srk2

Aug 15th, 2005, 10:38 AM	#5
Hadrurus Newbie Join Date: Aug 2005 Location: Northampton, England Posts: 8 Rep Power: 0	Thanks Ooble and Skuinders both your help much appreciated The program works perfectly now. thanks again, __________________ -Hadrurus Even if the voices aren't real, they have some good ideas.

Aug 15th, 2005, 12:50 PM	#6
Navid Hobbyist Programmer Join Date: Feb 2005 Location: Canada Posts: 187 Rep Power: 4	Speaking of a random number, how would you get a random number in C? I'm curious about manipulating the range of the random number too.

Aug 15th, 2005, 1:08 PM	#7
skuinders Hobbyist Programmer Join Date: Jun 2005 Location: MA, US Posts: 204 Rep Power: 4	http://cplus.about.com/od/cprogrammi.../aa041403c.htm __________________ "A stupid man's report of what a clever man says can never be accurate, because he unconciously translates what he hears into something he can understand." - B. Russell http://web.bryant.edu/~srk2

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Programming Forums > Application Development > Java

Random Number & Average Problem