Help!! Exception in thread "main" java.lang.NullPointerException
Hi i'm new to java and was wondering what this exception means? heres my code..
/**
* @(#)setGame.java
*
*
* @author
* @version 1.00 2007/2/20
*/
import java.io.*;
class card{
private String number;
private String shape;
private String colour;
private String shading;
public void setShading(String shde){
if(shde.equals("filled")||shde.equals("striped")||shde.equals("empty") ){
shading = shde;
}
else{
System.out.println("error shading property does not compute.");
}
}
public void setColour(String colr){
if(colr.equals("red")||colr.equals("green")||colr.equals("purple")){
colour = colr;
}
else{
System.out.println("error colour property does not compute.");
}
}
public void setShape(String shp){
if(shp.equals("round")||shp.equals("diamond")||shp.equals("squiggly")){
shape = shp;
}
else{
System.out.println("error shape property does not compute.");
}
}
public void setNumber(String num){
if(num.equals("1")||num.equals("2")||num.equals("3")){
number = num;
}
else{
System.out.println("error shape property does not compute.");
}
}
public void DisplayCard(){
System.out.print(number + " ");
System.out.print(shape + " ");
System.out.print(colour + " ");
System.out.print(shading + " ");
System.out.println("");
}
}
class deck{
}
public class setGame {
/**
* Creates a new instance of <code>setGame</code>.
*/
public setGame() {
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
card [] cardDeck = new card[81];
// TODO code application logic here
System.out.println("Welcome to Set game!.");
//Creating the shading, shape, and colour properties
//for the 81 cards and storing them into an array.
for(int i=0;i<81;i++){
if(i/27==0){
cardDeck.setShading("filled");
if(i/9==0){
cardDeck.setShape("round");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==1){
cardDeck.setShape("diamond");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==2){
cardDeck.setShape("squiggly");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
}
else if(i/27==1){
cardDeck.setShading("striped");
if(i/9==0){
cardDeck.setShape("round");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==1){
cardDeck.setShape("diamond");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==2){
cardDeck.setShape("squiggly");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
}
else if(i/27==2){
cardDeck.setShading("empty");
if(i/9==0){
cardDeck.setShading("round");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==1){
cardDeck.setShading("diamond");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
else if(i/9==2){
cardDeck.setShading("squiggly");
if(i/3==0){
cardDeck.setColour("red");
}
else if(i/3==1){
cardDeck.setColour("green");
}
else if(i/3==2){
cardDeck.setColour("purple");
}
}
}
}
//Creating the Number property for the 81 cards
//and storing them into an array.
for(int i=0;i<81;i=i+3){
cardDeck.setNumber("1");
}
for(int i=1;i<81;i=i+3){
cardDeck.setNumber("2");
}
for(int i=2;i<81;i=i+3){
cardDeck.setNumber("3");
}
for(int i=0;i<81;i++)
cardDeck.DisplayCard();
}
}
