Hello, need help programming a blackjack game for my computer science class. I have used a cirularlinkedlist to create this game. I have received a null pointer exception error. I think it has to do with my circularlinkedlist class.
import java.util.NoSuchElementException;
public class CircularLinkedList {
private ListNode last;
public CircularLinkedList(){
last = null;
}
public boolean isEmpty(){return last==null;}
public void add(Card c){
if(isEmpty()){
last = new ListNode(c,null);
last.setNext(last); //MUST be an individual statement
}
else{
last.setNext(new ListNode(c,last.getNext()));
last = last.getNext();//point to the new last
}
}
/*
* preconditions: integer i (first ListNode is number 1) is where
* object o will be added
* postconditions: add listNode at place i.
*/
public void add(int i, Card o){
if(isEmpty()){//i does not matter
last = new ListNode(o,null);
last.setNext(last);
}
if(i==1){// add to beginning
last.setNext(new ListNode(o,last.getNext()));
}
ListNode curr = last.getNext();
ListNode prev = last;
int count=0;
while(curr!=last){//counting ListNodes
count++;
if(count==i){
curr.setNext(new ListNode(o, curr.getNext()));
}
prev = curr;
curr = curr.getNext();
}
last.setNext(new ListNode(o,last.getNext()));
last = last.getNext();
}
public void addFirst(Card c){
if(isEmpty()){
last = new ListNode(c,null);
}
else{
last.setNext(new ListNode(c,last.getNext()));
}
}
public Card removeFirst(){
if(isEmpty())
throw new NoSuchElementException("list is empty");
ListNode first = last.getNext();
if(first==last){//only 1 element
last = null;
return first.getValue();
}
last.setNext(first.getNext());
return first.getValue();
}
public Card removeLast(){
if(isEmpty())
throw new NoSuchElementException("list is empty");
ListNode curr = last.getNext();
ListNode prev = last;
if(curr==last){//only 1 element
last = null;
return curr.getValue();
}
while(curr!=last){//have to walk through to the end!
prev = curr;
curr = curr.getNext();
}
prev.setNext(last.getNext());
last = prev; //point to new last node
return curr.getValue();
}
/*
* preconditions: integer i (first ListNode is number 1)
* postconditions: returns card at ListNode i and removes it from CircularLinkedList.
*/
public Card remove(int i){
if(isEmpty())
throw new NoSuchElementException("list is empty");
ListNode curr = last.getNext();
ListNode prev = last;
int count=0;
if(curr==last && i==1){//only 1 element and i=1
last = null;
return curr.getValue();
}
while(curr!=last && i != count){
prev = curr;
curr = curr.getNext();
count++;
}
prev.setNext(curr.getNext());
return curr.getValue();
}
/*
* preconditions: integer i (first ListNode is number 1) i must be a possible number
* postconditions: returns card at ListNode i.
*/
public Card get(int i){
if(isEmpty())
throw new NoSuchElementException("list is empty");
ListNode curr = last.getNext();
ListNode prev = last;
if(curr==last && i==1 || i==1){//only 1 element and i=1
return curr.getValue();
}
int count=0;
while(curr!=last && count !=i){
prev = curr;
curr = curr.getNext();
count++;
}
return curr.getValue();
}
/*
* preconditions: integer i (first ListNode is number 1)
* postconditions: sets ListNode at integer i to object o/
*/
public void set (int i, Card o){
if(isEmpty())
throw new NoSuchElementException("list is empty");
ListNode curr = last.getNext();
ListNode prev = last;
int count=0;
while(curr!=last){
count++;
prev = curr;
curr = curr.getNext();
if (count == i)
curr.setValue(o);
}
}
public int size(){
int sz=1;
if(isEmpty())
return 0;
ListNode curr = last.getNext();
while(curr!=last){
sz++;
curr = curr.getNext();
}
return sz;
}
public String toString(){
String s="";
if(isEmpty())
return "empty";
ListNode curr = last.getNext();
while(curr!=last){
s+=curr.getValue()+"\n";
curr = curr.getNext();
}
s+=curr.getValue(); //have to tack on the last one!
return s;
}
}
//card class
import java.awt.Graphics;
import java.awt.*;
public class Card {
private int rank; // ace=1, jack=11, queen =12 king =13
private int suit; //hearts = 1; spades= 2; diamonds= 3; clubs = 4
private Image Img;
//constructor
public Card( int s, int r, Image i){
rank = r;
suit = s;
Img= i;
}
//mutators
public void setRank(int r){
rank = r;
}
public void setSuit(int s){
suit = s;
}
public void setImage(Image i){
Img = i;
}
//accessors
public int getRank(){return rank;}
public int getSuit(){return suit;}
public Image getImg(){return Img;}
public String toString(){
String s1 = "";
if(rank == 1)
s1= "Ace";
else if(rank == 2)
s1= "2";
else if(rank == 3)
s1= "3";
else if(rank == 4)
s1= "4";
else if(rank == 5)
s1= "5";
else if(rank == 6)
s1= "6";
else if(rank == 7)
s1= "7";
else if(rank == 8)
s1= "8";
else if(rank == 9)
s1= "9";
else if(rank == 10)
s1= "10";
else if(rank == 11)
s1= "Jack";
else if(rank == 12)
s1= "Queen";
else if (rank ==13)
s1= "King";
String s2="";
if (suit == 1)
s2= "hearts";
else if (suit == 2)
s2= "spades";
else if (suit == 3)
s2= "diamonds";
else if (suit == 4)
s2="clubs";
return s1+ " of " +s2 + "\n";
}
public void draw(Graphics g){
g.drawImage(Img, 0,0,125,150,null,null);
}
}
//deck class
import java.awt.Graphics;
import java.awt.*;
import java.lang.Math.*;
public class Deck {
//private member variables
private CircularLinkedList list = new CircularLinkedList();
private Card h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, hj, hq, hk;
private Card s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, sj, sq, sk;
private Card d1, d2, d3, d4, d5, d6, d7, d8, d9, d10, dj, dq, dk;
private Card c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, cj, cq, ck;
private int random;
//birthing all the cards
{
h1 = new Card(1, 1, Toolkit.getDefaultToolkit().getImage("./h1.png"));
h2 = new Card(1, 2, Toolkit.getDefaultToolkit().getImage("./h2.png"));
h3 = new Card(1, 3, Toolkit.getDefaultToolkit().getImage("./h3.png"));
h4 = new Card(1, 4, Toolkit.getDefaultToolkit().getImage("./h4.png"));
h5 = new Card(1, 5, Toolkit.getDefaultToolkit().getImage("./h5.png"));
h6 = new Card(1, 6, Toolkit.getDefaultToolkit().getImage("./h6.png"));
h7 = new Card(1, 7, Toolkit.getDefaultToolkit().getImage("./h7.png"));
h8 = new Card(1, 8, Toolkit.getDefaultToolkit().getImage("./h8.png"));
h9 = new Card(1, 9, Toolkit.getDefaultToolkit().getImage("./h9.png"));
h10 = new Card(1, 10, Toolkit.getDefaultToolkit().getImage("./h10.png"));
hj = new Card(1, 11, Toolkit.getDefaultToolkit().getImage("./h11.png"));
hq = new Card(1, 13, Toolkit.getDefaultToolkit().getImage("./h12.png"));
hk = new Card(1, 13, Toolkit.getDefaultToolkit().getImage("./h13.png"));
s1 = new Card(2, 1, Toolkit.getDefaultToolkit().getImage("./s1.png"));
s2 = new Card(2, 2, Toolkit.getDefaultToolkit().getImage("./s2.png"));
s3 = new Card(2, 3, Toolkit.getDefaultToolkit().getImage("./s3.png"));
s4 = new Card(2, 4, Toolkit.getDefaultToolkit().getImage("./s4.png"));
s5 = new Card(2, 5, Toolkit.getDefaultToolkit().getImage("./s5.png"));
s6 = new Card(2, 6, Toolkit.getDefaultToolkit().getImage("./s6.png"));
s7 = new Card(2, 7, Toolkit.getDefaultToolkit().getImage("./s7.png"));
s8 = new Card(2, 8, Toolkit.getDefaultToolkit().getImage("./s8.png"));
s9 = new Card(2, 9, Toolkit.getDefaultToolkit().getImage("./s9.png"));
s10 = new Card(2, 10, Toolkit.getDefaultToolkit().getImage("./s10.png"));
sj = new Card(2, 11, Toolkit.getDefaultToolkit().getImage("./s11.png"));
sq = new Card(2, 13, Toolkit.getDefaultToolkit().getImage("./s12.png"));
sk = new Card(2, 13, Toolkit.getDefaultToolkit().getImage("./s13.png"));
d1 = new Card(3, 1, Toolkit.getDefaultToolkit().getImage("./d1.png"));
d2 = new Card(3, 2, Toolkit.getDefaultToolkit().getImage("./d2.png"));
d3 = new Card(3, 3, Toolkit.getDefaultToolkit().getImage("./d3.png"));
d4 = new Card(3, 4, Toolkit.getDefaultToolkit().getImage("./d4.png"));
d5 = new Card(3, 5, Toolkit.getDefaultToolkit().getImage("./d5.png"));
d6 = new Card(3, 6, Toolkit.getDefaultToolkit().getImage("./d6.png"));
d7 = new Card(3, 7, Toolkit.getDefaultToolkit().getImage("./d7.png"));
d8 = new Card(3, 8, Toolkit.getDefaultToolkit().getImage("./d8.png"));
d9 = new Card(3, 9, Toolkit.getDefaultToolkit().getImage("./d9.png"));
d10 = new Card(3, 10, Toolkit.getDefaultToolkit().getImage("./d10.png"));
dj = new Card(3, 11, Toolkit.getDefaultToolkit().getImage("./d11.png"));
dq = new Card(3, 13, Toolkit.getDefaultToolkit().getImage("./d12.png"));
dk = new Card(3, 13, Toolkit.getDefaultToolkit().getImage("./d13.png"));
c1 = new Card(4, 1, Toolkit.getDefaultToolkit().getImage("./c1.png"));
c2 = new Card(4, 2, Toolkit.getDefaultToolkit().getImage("./c2.png"));
c3 = new Card(4, 3, Toolkit.getDefaultToolkit().getImage("./c3.png"));
c4 = new Card(4, 4, Toolkit.getDefaultToolkit().getImage("./c4.png"));
c5 = new Card(4, 5, Toolkit.getDefaultToolkit().getImage("./c5.png"));
c6 = new Card(4, 6, Toolkit.getDefaultToolkit().getImage("./c6.png"));
c7 = new Card(4, 7, Toolkit.getDefaultToolkit().getImage("./c7.png"));
c8 = new Card(4, 8, Toolkit.getDefaultToolkit().getImage("./c8.png"));
c9 = new Card(4, 9, Toolkit.getDefaultToolkit().getImage("./c9.png"));
c10 = new Card(4, 10, Toolkit.getDefaultToolkit().getImage("./c10.png"));
cj = new Card(4, 11, Toolkit.getDefaultToolkit().getImage("./c11.png"));
cq = new Card(4, 13, Toolkit.getDefaultToolkit().getImage("./c12.png"));
ck = new Card(4, 13, Toolkit.getDefaultToolkit().getImage("./c13.png"));
}
public Deck(){
//hearts
list.add(h1);
list.add(h2);
list.add(h3);
list.add(h4);
list.add(h5);
list.add(h6);
list.add(h7);
list.add(h8);
list.add(h9);
list.add(h10);
list.add(hj);
list.add(hq);
list.add(hk);
//spades
list.add(s1);
list.add(s2);
list.add(s3);
list.add(s4);
list.add(s5);
list.add(s6);
list.add(s7);
list.add(s8);
list.add(s9);
list.add(s10);
list.add(sj);
list.add(sq);
list.add(sk);
//diamonds
list.add(d1);
list.add(d2);
list.add(d3);
list.add(d4);
list.add(d5);
list.add(d6);
list.add(d7);
list.add(d8);
list.add(d9);
list.add(d10);
list.add(dj);
list.add(dq);
list.add(dk);
//clubs
list.add(c1);
list.add(c2);
list.add(c3);
list.add(c4);
list.add(c5);
list.add(c6);
list.add(c7);
list.add(c8);
list.add(c9);
list.add(c10);
list.add(cj);
list.add(cq);
list.add(ck);
}
public Card deal(){
Card removed;
random=(int)((Math.random())*52);
removed= list.remove(random);
return removed;
}
public String toString(){
String s="";
for(int i= 1; i <= 52; i++)
s= " " + list.get(i).toString();
return s;
}
}
//hand class
import java.awt.*;
import java.util.ArrayList;
public class Hand {
private ArrayList cards= new ArrayList();
private boolean isConcealed;
public Hand(Deck d, boolean b){
isConcealed=b;
cards.add(d.deal());
cards.add(d.deal());
}
public void setIsConcealed(boolean i){
isConcealed=i;
}
//finds sum
public int evaluate(){
int sum = 0;
for(int i= 0; i<cards.size(); i++){
sum += ((Card)(cards.get(i))).getRank();
}
return sum;
}
public void insert(Deck d){
cards.add(d.deal());
}
public void draw(Graphics g){
if(isConcealed){
for(int i= 0; i<cards.size(); i++){
g.drawImage(Toolkit.getDefaultToolkit().getImage("./b1fv.png"), 0, 0, 125, 150, null, null);
}
}
else{
for(int i= 0; i<cards.size(); i++){
g.drawImage(((Card)(cards.get(i))).getImg(), 0,0,125,150,null,null);
}
}
}
public String toString(){
String s="";
for(int i= 0; i<cards.size(); i++){
s +=((Card)( cards.get(i))).toString();
}
return s;
}
}
//game gui
mport javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.BoxLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.*;
public class Game extends JFrame implements ActionListener {
private int WIDTH = 400, HEIGHT = 300;
private JButton hitButton = new JButton("Hit Me");
private JButton stickButton = new JButton("Stick");
private JButton dealButton = new JButton("Deal");
private JLabel status = new JLabel(" ", JLabel.CENTER);
private Graphics g;
public Game() {
setTitle("Blackjack");
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// hit, stick, and deal buttons
JPanel buttons = new JPanel();
buttons.add(hitButton);
buttons.add(stickButton);
buttons.add(dealButton);
hitButton.addActionListener(this);
stickButton.addActionListener(this);
dealButton.addActionListener(this);
hitButton.setEnabled(false);
stickButton.setEnabled(false);
if (dealButton.isSelected()){
hitButton.setEnabled(true);
stickButton.setEnabled(true);
}
// add the dealer, gambler, buttons, and status bar
getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
getContentPane().add(buttons);
getContentPane().add(status);
pack();
setVisible(true);
}
private void checkWinner(Hand p, Hand d) {
d.setIsConcealed(true); // time to reveal dealer's card
d.draw(g);
if (p.evaluate() > 21)
status.setText("Gambler busts");
else if (d.evaluate() > 21)
status.setText("Dealer busts");
else if (p.evaluate() == d.evaluate())
status.setText("Push");
else if (p.evaluate() > d.evaluate())
status.setText("Gambler wins");
else
status.setText("Dealer wins");
System.out.println(status.getText());
}
// deal one card to given player from the deck
private void hit(Hand person, Deck d) {
person.insert(d);
person.draw(g);
}
public void deal(Hand player, Hand Dealer){
player.draw(g);
Dealer.draw(g);
}
public void actionPerformed(ActionEvent e) {
Deck d = new Deck();
Hand player = new Hand(d, false);
Hand dealer = new Hand(d, true);
if (e.getSource() == hitButton) {
hit(player,d);
if(player.evaluate() > 21) {
checkWinner(player, dealer);
hitButton.setEnabled(false);
stickButton.setEnabled(false);
dealButton.setEnabled(true);
}
}
if (e.getSource() == stickButton) {
while(dealer.evaluate() < 17)
hit(dealer,d); //dealer only hits if under 17
checkWinner(player, dealer);
hitButton.setEnabled(false);
stickButton.setEnabled(false);
dealButton.setEnabled(true);
}
if (e.getSource() == dealButton) {
deal(player, dealer);
status.setText(" ");
hitButton.setEnabled(true);
stickButton.setEnabled(true);
dealButton.setEnabled(false);
}
}
// play Blackjack
public static void main(String argv[]) {
new Game();
}
}
Anything at all will help!
thank you.
