Greenfoot

ronzhi wrote ...

2013/4/8

non-repeating random number help

ronzhi

2013/4/8

Hi,need a little help here i want to create enemies that pop out 5 random questions out of 6 and can't be taken twice while the enemies number and position is fix in the world class i already use random number method but still can be taken twice how do i do this? any help would be appreciated this is my world class

addObject(new ProEnemy(1), 350, 510);
addObject(new ProEnemy(2), 780, 510);
addObject(new ProEnemy(3), 666, 294);
addObject(new ProEnemy(4), 968, 210);
addObject(new ProEnemy(5), 155, 210);

this is my ProEnemy class

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.*;
import javax.swing.JOptionPane;
import java.awt.Point;
import javax.swing.JDialog;
import javax.swing.JFrame;

/**
 * Write a description of class Addition here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class ProEnemy extends Enemies
{
    ...
	...
    private int number = getRandomNumber(1,6);
    public int newSpot1 = getRandomNumber(120,370);
    public int newSpot2 = getRandomNumber(640,850);
    public int newSpot3 = getRandomNumber(656,868);
    public int newSpot4 = getRandomNumber(440,550);
    public int newSpot5 = getRandomNumber(179,390);
            
    JFrame frame;
    
    public ProEnemy(int voucher)
    {
        ticket = voucher;
    }
    
    public void addedToWorld(World World)
    {
        getPosition();
    }
        
    public void getPosition()
    {
        if(ticket==1)
            setMove(120,370,1,-1);
        if(ticket==2)
            setMove(640,850,1,-1);
        if(ticket==3)
            setMove(656,868,1,1);
        if(ticket==4)
            setMove(968,968,0,-1);
        if(ticket==5)
            setMove(179,390,1,1);    
    }
    
    public void respawn()
    {
        
        if(ticket==1)
            getWorld().addObject (new ProEnemy (1), (newSpot1), 510);
        if(ticket==2)
            getWorld().addObject (new ProEnemy (2), (newSpot2), 510);
        if(ticket==3)
            getWorld().addObject (new ProEnemy (3), (newSpot3), 294);
        if(ticket==4)
            getWorld().addObject (new ProEnemy (4), 968, 210);
        if(ticket==5)
            getWorld().addObject (new ProEnemy (5), (newSpot5), 210);
    }
    
    setMove()
	..
	..

    public void act() 
    {
        animate();
        movement
		..
		..
		touchingPlayer();
    }

    animate()
	..
	..
    
    public boolean touchingPlayer()
    {
        Actor touchingPlayer = getOneObjectAtOffset(0, 0, Player.class);
        if(touchingPlayer != null) 
        {
            throwQuestion();
            getWorld().removeObject(this);
        }
        return touchingPlayer!=null;
    }
    
    public int getRandomNumber(int start,int end)  
    {  
       int normal = Greenfoot.getRandomNumber(end-start+1);  
       return normal+start;  
    }
    
    public void throwQuestion()
    {
        if (number == 1)
        {
            int answer = 0;
            String input = JOptionPane.showInputDialog(null, "1+1 = ?");
            if (input == null)
            {
                errorQuestion();
            }
            else
            {
                try
                {
                    answer = Integer.parseInt(input);
                    if (answer == 2)
                    {
                        JOptionPane.showMessageDialog(frame,"good");
                    }
                    else
                    {
                        int reply = JOptionPane.showConfirmDialog(null, "do you want to retry ?", "wrong answer", JOptionPane.YES_NO_OPTION);
                        if (reply == JOptionPane.YES_OPTION)
                        {
                            throwQuestion();
                        }
                        else
                        {
                            respawn();
                        }
                    }
                }
                catch(Exception ex)
                {
                    errorQuestion();
                }
            }
        }
        ..
		..
		repeat until number == 6
    }
    
    public void errorQuestion()
    {
        try
        {
            respawn();
        }   
        catch(Exception ex)
        {

        }
    }
}

Gevater_Tod4711

2013/4/8

If you save the values that were already teaken (in an array or some variables) you can check whether the value that you choose was already taken. If it was already taken you try another. You should do this in a loop because in the worst case it'll never be true and that would be an awefull lot of code if you don't do this in a loop.

ronzhi

2013/4/8

would you please give little example Gevater? have no idea where i put the loop, in the act or addedToWorld?

Gevater_Tod4711

2013/4/8

I'm not sure but I think the random number you are using is in the constructor. So you have to add this loop whereever the new objects are created.It's not in this class I think.

danpost

2013/4/8

An easy way to randomly select 5 out of 6 is by using a simple little trick:

// add this instance field
String options = "123456"; // list of option values for questions
// then, in act or method it calls
if (options.length() > 1)
{
    int opt = Greenfoot.getRandomNumber(options.length())// random shuffle value
    for (int i=0; i<opt; i++) options = options.substring(1)+options.charAt(0); // shuffle
    number = Integer.valueOf(""+options.charAt(0)); // get question number
    options = options.substring(1); // remove question from options
    // throw the question here
}
else // not throwing question anymore (or yet)

It does not matter if 'opt' does not equal 'number' as each question will still have the same chance of being picked at any choosing. 'opt' will actually refer to the position in the 'opts' string, as it is at the moment, that is chosen.

ronzhi

2013/4/9

thanks danpost,i'll try it out

ronzhi

2013/4/9

first question often got repeat in last question and sometimes got repeat twice in 3rd and last i put it in method that called when player touch the enemies is it correct?

public void throwQuestion()
    {
        if (options.length() > 1)  
        {  
            int opt = Greenfoot.getRandomNumber(options.length());// random shuffle value
            for (int i=0; i<opt; i++)
            options = options.substring(1)+options.charAt(0); // shuffle  
            number = Integer.valueOf(""+options.charAt(0)); // get question number  
            options = options.substring(1); // remove question from options  
            // throw the question here  
            System.out.print(number);
			if (number == 1)
			{
				int answer = 0;
				String input = JOptionPane.showInputDialog(null, "1+1 = ?");
				if (input == null)
				{
					errorQuestion();
				}
				else
				{
					try
					{
						answer = Integer.parseInt(input);
						if (answer == 2)
						{
							JOptionPane.showMessageDialog(frame,"good");
						}
						else
						{
							int reply = JOptionPane.showConfirmDialog(null, "do you want to retry ?", "wrong answer", JOptionPane.YES_NO_OPTION);
							if (reply == JOptionPane.YES_OPTION)
							{
								throwQuestion();
							}
							else
							{
								respawn();
                            }
						}
					}
					catch(Exception ex)
					{
						errorQuestion();
					}
				}
			}       
		}
    }

danpost

2013/4/9

Your questions should not repeat unless you restore the value of the String 'options'. Unless I see how the rest of your code goes with this, I could not help you.

ronzhi

2013/4/9

the rest of code is same as my first post with addition of yours in the throwQuestion method i know the questions repetition is a mess,but that's what come to my head at this time any suggestion/improvement would be a great help

danpost

2013/4/9

Ther was some code you left out when you put in

...
...

ronzhi

2013/4/9

oh sorry, in the throwQuestions method that was for questions 1 until 6 the difference is just the question like this

if (number == 1)  
        {  
            int answer = 0;  
            String input = JOptionPane.showInputDialog(null, "1+1 = ?");  
            if (input == null)  
            {  
                errorQuestion();  
            }  
            else  
            {  
                try  
                {  
                    answer = Integer.parseInt(input);  
                    if (answer == 2)  
                    {  
                        JOptionPane.showMessageDialog(frame,"good");  
                    }  
                    else  
                    {  
                        int reply = JOptionPane.showConfirmDialog(null, "do you want to retry ?", "wrong answer", JOptionPane.YES_NO_OPTION);  
                        if (reply == JOptionPane.YES_OPTION)  
                        {  
                            throwQuestion();  
                        }  
                        else  
                        {  
                            respawn();  
                        }  
                    }  
                }  
                catch(Exception ex)  
                {  
                    errorQuestion();  
                }  
            }  
        }
if (number == 2)  
        {  
            int answer = 0;  
            String input = JOptionPane.showInputDialog(null, "3+7 = ?");  
            if (input == null)  
            {  
                errorQuestion();  
            }  
            else  
            {  
                try  
                {  
                    answer = Integer.parseInt(input);  
                    if (answer == 10)  
                    {  
                        JOptionPane.showMessageDialog(frame,"good");  
                    }  
                    else  
                    {  
                        int reply = JOptionPane.showConfirmDialog(null, "do you want to retry ?", "wrong answer", JOptionPane.YES_NO_OPTION);  
                        if (reply == JOptionPane.YES_OPTION)  
                        {  
                            throwQuestion();  
                        }  
                        else  
                        {  
                            respawn();  
                        }  
                    }  
                }  
                catch(Exception ex)  
                {  
                    errorQuestion();  
                }  
            }  
        }
//until if (number == 6) with different qestions

danpost

2013/4/10

You could probably save yourself a lot of anguish and pain by using arrays for your question sets. Declare then as static final Strings using a double array. The major array for the question sets; the minor for the question themselves.

private static final String[][] Q =
    { { "1+1", "3+7", "5+3", "8+6", "2+4", "9+5" },
      { "4+7", "5+6", "8+8", "7+9", "0+6", "3+4" } };
private int qSet;
private String options = "123456";

I only show two sets of question here, but you can add as many groups of question as you need. I also show the other fields you will need. Use the int field 'qSet' to track which question set you are on, and use one set of code for ALL the questions. Right now, any change you make in one, you have to make in all 6 codings for each question. If you have not worked with arrays before, they are not that difficult to understand. You can refer to any element in the array by 'Q' (ex. Q refers to the fifth question in the second set (remember java starts counting at zero) which is "0+6". With this knowledge, you can see that you can refer to any element by 'Q'. You can also create an array of answer in the same way and check the input responses to the elements in that array. The answer array can be set up exactly the same way as the question array; the only difference being the question array is a String array and the answer array will be an int array.

private static final int A[][] =
    { { 2, 10, 8, 14, 6, 14 }, { 11, 11, 16, 16, 6, 7 } };

danpost

2013/4/10

NVM

ronzhi

2013/4/10

that's awesome danpost,i got it but how to compare if Q is = A using this double array with your trick before? and i try your code w/o throw question and print the result it still has repeat questions when the opt randomly got same number twice

danpost

2013/4/10

The following is not tested, but should be close to what you are looking for. It could probably be the entire body of your 'throwQuestion' method.

if (options.length < 2)
{
    options = "123456";
    qSet++;
    if (qS > 5) qSet = 0; // replace '5' with number of sets of questions you have
}
int opt = Greenfoot.getRandomNumber(options.length())
for (int i=0; i<opt; i++) options = options.substring(1)+options.charAt(0);
number = Integer.valueOf(""+options.charAt(0));
options = options.substring(1);
int reply = JOptionPane.YES_OPTION;
while (reply == JOptionPane.YES_OPTION)
{
    int answer = 0;  
    String input = JOptionPane.showInputDialog(null, Q[qSet][number]+" = ?");  
    if (input == null)  
    {  
        errorQuestion();  
    }  
    else  
    {  
        try  
        {  
            answer = Integer.parseInt(input);  
            if (answer == A[qSet][number])
            {  
                JOptionPane.showMessageDialog(frame, "good");
            }  
            else  
            {  
                reply = JOptionPane.showConfirmDialog(null, "do you want to retry ?", "wrong answer", JOptionPane.YES_NO_OPTION);
            }
        }
        catch(Exception ex)  
        {  
            errorQuestion();  
        }  
    }
}
if (reply != JOptionPane.YES_OPTION) respawn();

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non-repeating random number help