Picking randomly

[AbdulAziz Bader]

Hello... I`m creating a program that shows an questions with an mutable answers, but I won’t the questions shows randomly and not in the same sequence, that`s also on the answers. the problem is that I don`t know how to implement it.

AbdulAziz Al-Khars

[r035198x]

See the API specs for the java.util.Random class.

[Eranga]

Keep a collection, a map, with the question number and the question. Randomly pick the number and get the question. Solution is java.util.Random as r035198x says.

Search on the forum, you can find lots of related.

[thomasdevos]

Eranga, i do agree with you.
at the same time, AbdulAziz Bader, you may try method shuffle of Collections:

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


public class RandomQuestion {
	public static void main(String[] args) {
		List qs = new ArrayList();
		qs.add("what is your name?");
		qs.add("how old are you?");
		qs.add("where are you?");
		
		Collections.shuffle(qs);
		System.out.println(qs.get(0));
		
	}
}

Thomas Devos

Keep a collection, a map, with the question number and the question. Randomly pick the number and get the question. Solution is java.util.Random as r035198x says.

Search on the forum, you can find lots of related.

[Eranga]

Actually you've to keep them in a collection as value pairs, question and the question number, as a key value pair. Pick the key randomly and refer the relevant value from it.

[Eranga]

The following will gives you a better explanation.

The Map Interface (The Java™ Tutorials > Collections > Interfaces)

[AbdulAziz Bader]

First of all thanks for helping me with this code,
In my program I'm trying to make three different packages, every package contains around 10 to 15 questions, and the code that you gave me will pick a random package for the user, and as usually I faced problems in implementing this idea, so any hints or suggestions.

[Eranga]

Okay, for the moment just forget about the coding part. Think about the logic. If I'm correct you have question packages, let we named them as P1, P2, P3, ... And in each package you have several questions. So basically the following kind of mapping is there.

P1 -> Q1 -> Your name
-> Q2 -> Age

P2 -> I -> Full name
-> II -> Address

and so on... Is that clear to you?

[Eranga]

And according to your requirement, what you want to do is, pick a package randomly and chose questions withing that package randomly, is it?

[AbdulAziz Bader]

sorry but the logic thing is not clear... could you help me more please

[AbdulAziz Bader]

i got the logic but there is some problems in the implementation :confused:
thats the code if you dont mind in helping me

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Easy extends javax.swing.JFrame {

    /** Creates new form Easy */
    String[] Question={"whats my name", "how old am i ", "whats my fathers name"};
    String[] A={"abdullah", "16", "bader"};
    String[] B={"AbdulAziz", "19", "fahad"};
    String[] C={"khaled", "21", "jamal"};
    String[] D={"bader", "20", "sameer"};



    public Easy() {
        initComponents();
    }

    
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        buttonGroup1 = new javax.swing.ButtonGroup();
        jButton1 = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        jButton2 = new javax.swing.JButton();
        jRadioButton1 = new javax.swing.JRadioButton();
        jRadioButton2 = new javax.swing.JRadioButton();
        jButton3 = new javax.swing.JButton();
        jLabel2 = new javax.swing.JLabel();
        jButton4 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setResizable(false);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowOpened(java.awt.event.WindowEvent evt) {
                formWindowOpened(evt);
            }
        });

        jButton1.setText("Back To Main Menu");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jLabel1.setText("Are you Ready");
        jLabel1.addInputMethodListener(new java.awt.event.InputMethodListener() {
            public void caretPositionChanged(java.awt.event.InputMethodEvent evt) {
            }
            public void inputMethodTextChanged(java.awt.event.InputMethodEvent evt) {
                jLabel1InputMethodTextChanged(evt);
            }
        });

        jButton2.setText("Exit");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jButton3.setText("jButton3");
        jButton3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton3ActionPerformed(evt);
            }
        });

        jLabel2.setText("jLabel2");

        jButton4.setText("Next");
        jButton4.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton4ActionPerformed(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()
                .addGap(30, 30, 30)
                .addComponent(jLabel1)
                .addContainerGap(306, Short.MAX_VALUE))
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jRadioButton2)
                        .addContainerGap())
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jRadioButton1)
                            .addContainerGap())
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jButton1)
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 197, Short.MAX_VALUE)
                            .addComponent(jButton2)
                            .addGap(23, 23, 23)))))
            .addGroup(layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addComponent(jButton3)
                .addGap(61, 61, 61)
                .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 85, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 78, Short.MAX_VALUE)
                .addComponent(jButton4)
                .addGap(32, 32, 32))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(25, 25, 25)
                .addComponent(jLabel1)
                .addGap(44, 44, 44)
                .addComponent(jRadioButton1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jRadioButton2)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 103, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton3)
                    .addComponent(jLabel2)
                    .addComponent(jButton4))
                .addGap(26, 26, 26)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jButton2))
                .addContainerGap())
        );

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

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
this.setVisible(false);
      new Difficulty().setVisible(true);

    
    }                                        

    private void jLabel1InputMethodTextChanged(java.awt.event.InputMethodEvent evt) {                                               

       

    }                                              

    private void formWindowOpened(java.awt.event.WindowEvent evt) {                                  


      //  jRadioButton1.setText("ssss");

        

         List qs = new ArrayList();
		qs.add(1);
                qs.add(2);
                qs.add(3);
//                qs.add(4);
//                qs.add(5);
//                qs.add(6);
//                qs.add(7);
//                qs.add(8);
//                qs.add(9);
//                qs.add(10);

		Collections.shuffle(qs);
	jLabel1.setText("" + qs.get(0));


    }                                 

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
System.exit(0);    
    }                                        

    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
 jLabel2.setText(jRadioButton1.getText());

    }                                        

    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         

        jLabel1.setText(Question[0]);
        jLabel1.setText(Question[1]);
        jLabel1.setText(Question[2]);
    }                                        

    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Easy().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.ButtonGroup buttonGroup1;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton3;
    private javax.swing.JButton jButton4;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JRadioButton jRadioButton1;
    private javax.swing.JRadioButton jRadioButton2;
    // End of variables declaration                   

}

[AbdulAziz Bader]

the "jbutton3" is just for testing

[Eranga]

sorry but the logic thing is not clear... could you help me more please

Which part you are not clear with?

[Eranga]

Could you please explain what you are going to do here?

String[] Question={"whats my name", "how old am i ", "whats my fathers name"};
    String[] A={"abdullah", "16", "bader"};
    String[] B={"AbdulAziz", "19", "fahad"};
    String[] C={"khaled", "21", "jamal"};
    String[] D={"bader", "20", "sameer"};

[AbdulAziz Bader]

thats related some how to the answers

string A contains the first answer for every qustion
string B contains the second answer for every qustion... etc

for example lets say that the first qustion is " how old am i"
the answers will be
1-16
2-19
3-21
4-20

[Eranga]

So if you are keeping them in that order, then you have to access with the same index. Something like this,

Question[1], A[1], B[1], C[1]

and the number 1 is the value you are picking randomly.

[AbdulAziz Bader]

i have replaced the arraylist with random chosing

import java.util.Random;

    Random lottery = new Random();
    int x;

    String[] Question={"whats my name", "how old am i ", "whats my fathers name"};
    String[] A={"abdullah", "16", "bader"};
    String[] B={"AbdulAziz", "19", "fahad"};

jLabel1.setText(Question[x].toString());

what do you think about it ?, is it better than using the arraylist ?

[Eranga]

My question is that, how did you pick the value for x? I mean you must select it withing the length of the array.

Array list are much effective than, arrays. You've more control over that.