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Thread: Null Pointer Exception-Freecell

  1. #1
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    Default Null Pointer Exception-Freecell

    Hello, I am looking for some help for a class I have, I am currently getting a null pointer exception on line 10 of my Freecell.java class

    Here's my code:

    Freecell.java:
    import java.awt.*;
    import javax.swing.*;
    import java.util.*;
    public class Freecell extends JApplet{
    	Deck a = new Deck();
    	public static ArrayList [] piles = new ArrayList[8];
    	public void init() {
    		a = Deck.shuffle(a);
    		for(int i = 0; i<8; i++){
    			piles[i].add(new ArrayList());
    			Pile.makePile(a, i);
    		}
    		repaint();
    	}
    	public void paint (Graphics g){
     
    	}
    }

    Card.java:
    import java.awt.*;
    import javax.swing.*;
    import java.util.*;
    public class Card {
    	public int suite;
    	public int rank;
    	public Card(){
    		suite= 0;
    		rank=0;
    	}
    	public Card(int rnk, int sui){
    		rank = rnk;
    		suite = sui;
    	}
    	public static String cardString(Card crd){
    		int rnk = crd.rank;
    		int sui = crd.suite;
    		String output = new String();
    		if(rnk == 2){
    			output = "Two";
    		}else if(rnk == 3){
    			output = "Three";
    		}else if(rnk == 4){
    			output = "Four";
    		}else if(rnk == 5){
    			output = "Five";
    		}else if(rnk == 6){
    			output = "Six";
    		}else if(rnk == 7){
    			output = "Seven";
    		}else if(rnk == 8){
    			output = "Eight";
    		}else if(rnk == 9){
    			output = "Nine";
    		}else if(rnk == 10){
    			output = "Ten";
    		}else if(rnk == 11){
    			output = "Jack";
    		}else if(rnk == 12){
    			output = "Queen";
    		}else if(rnk == 13){
    			output = "King";
    		}else if(rnk == 14){
    			output = "Ace";
    		}else if(rnk == 0){
    			output = "Zero";
    		}else {
    			output = "" + rnk;
    		}
    		output += " of ";
    		if(sui == 1){
    			output += "Diamonds";
    		}else if(sui == 2){
    			output += "Hearts";
    		}else if(sui == 3){
    			output += "Clubs";
    		}else if(sui == 4){
    			output += "Spades";
    		}else if(sui == 0){
    			output += "Nothing";
    		}else{
    			output += sui;
    		}
    		return output;
    	}
    	public static String cardFileString(Card crd){
    		int rnk = crd.rank;
    		int sui = crd.suite;
    		String output = new String();
    		if(rnk == 2){
    			output = "2";
    		}else if(rnk == 3){
    			output = "3";
    		}else if(rnk == 4){
    			output = "4";
    		}else if(rnk == 5){
    			output = "5";
    		}else if(rnk == 6){
    			output = "6";
    		}else if(rnk == 7){
    			output = "7";
    		}else if(rnk == 8){
    			output = "8";
    		}else if(rnk == 9){
    			output = "9";
    		}else if(rnk == 10){
    			output = "t";
    		}else if(rnk == 11){
    			output = "j";
    		}else if(rnk == 12){
    			output = "q";
    		}else if(rnk == 13){
    			output = "k";
    		}else if(rnk == 14){
    			output = "a";
    		}else if(rnk == 0){
    			output = "0";
    		}else {
    			output = "e";
    		}
    		if(sui == 1){
    			output += "d";
    		}else if(sui == 2){
    			output += "h";
    		}else if(sui == 3){
    			output += "c";
    		}else if(sui == 4){
    			output += "s";
    		}else if(sui == 0){
    			output += "0";
    		}else{
    			output += "e";
    		}
    		output += ".gif";
    		return output;
    	}
    	public static Card getCard(int numb){
    		Card crd = new Card((((numb-1)%13)+2),(((numb -1)/13)+1));
    		return crd;
    	}
    }

    Deck.java:
    import java.awt.*;
    import javax.swing.*;
    import java.util.*;
    public class Deck {
    	public Card [] deck = new Card [52];
    	Deck(){
    		for(int i = 1; i < 53; i++){
    			Card crd = new Card();
    			crd = Card.getCard(i);
    			deck[i - 1] = crd;
    		}
    	}
    	public static Deck shuffle (Deck dk){
    		Deck tmp = dk;
    		for(int i = 0; i < 100; i++){
    			Random r = new Random();
    			int rnd1 = r.nextInt(51)+1;
    			int rnd2 = r.nextInt(51)+1;
    			Card temp = tmp.deck[rnd1];
    			tmp.deck[rnd1] = tmp.deck[rnd2];
    			tmp.deck[rnd2] = temp;
    		}
    		return tmp;
    	}
    }

    Pile.java:
    import java.awt.*;
    import javax.swing.*;
    import java.util.*;
    public class Pile {
    	public static ArrayList <Card> pile = new ArrayList();
    	public Pile() {
    		pile = pile;
    	}
    	public static void makePile (Deck dk, int num){
    		if(num < 1 || num > 8){
    			return;
    		}else{
    			for(int i = 44; i%8+num > -1; i--){
    				Freecell.piles[num].add(dk.deck[i]);
    			}
    		}
    	}
    }

    Any help would be appreciated,

    Thanks


  2. #2
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    Default Re: Null Pointer Exception-Freecell

    String[] words = new String[100];
    System.out.println(words[20].charAt(0));
    What do you expect the output to be?

    Let me put it another way, I am going to pick some apples but first I need to make a box to put them in. Once I have made the box how many apples are inside?
    Improving the world one idiot at a time!

  3. The Following User Says Thank You to Junky For This Useful Post:

    mnpeep (November 10th, 2011)

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