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how to select players join the game and start a game

I am a beginner in Java, and I've been creating a practicing project for a game. For this purpose, I've already put some features in this project, and I separate the entire project into three files: Nimsys, NimPlayer, NimGame.
I've created these features.
addplayer into playerList in the NimPlayer.
removeplayer
editplayer
Now, I want two of the players to join the game, and do the following:
Score record
The times the player has played.
What I did was trying to store the user data (addplayer) from the prompt input, and brought the game to be played (last part of the incomplete code).
import java.util.Scanner;
public class Nimsys {
public static String[] splitName(String inName) {
String[] splittedLine = inName.split(",");
String[] name = null;
if (splittedLine.length==3) {
String userName = splittedLine[0].trim();
String familyName = splittedLine[1].trim();
String givenName = splittedLine[2].trim();
name = new String[3];
name[0] = userName;
name[1] = familyName;
name[2] = givenName;
}
return name;
}
public static String [] splitData(String dataIn) {
String[] splittedLine = dataIn.split(",");
String[] data = null;
if (splittedLine.length==4) {
String initialStone = splittedLine[0];
String stoneRemoval = splittedLine[1];
String player1 = splittedLine[2].trim();
String player2 = splittedLine[3].trim();
data = new String[4];
data[0] = initialStone;
data[1] = stoneRemoval;
data[2] = player1;
data[3] = player2;
}
return data;
}
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
while (true) {
System.out.print('$');
String commandin = in.next();
if (commandin.equals("addplayer")) {
String inName = in.nextLine();
String[] name = splitName(inName);
//Make sure the vadality of in name
if (name!=null && name.length==3) {
for (int i = 0; i < NimPlayer.getId(); i ++) {
String userCheck = NimPlayer.getPlayer()[i].getUserName();
if (userCheck.contains(name[0])) {
System.out.println("The player already exist");//Test if player has been created
}
}
NimPlayer.createPlayer(name[0], name[1], name[2]);
System.out.println("The player has been created.");
} else {
System.out.println("Not Valid! Please enter again!");
}
}
if (commandin.equals("removeplayer")) {
//cannot loop through the entire null array, would be NullPointerException
String removeUserName = in.nextLine().trim();
/*System.out.println("Are you sure you want to remove all players? (y/n) \n");
//System.out.print('$');
commandin = in.next();
if (commandin.equals("y")) {
for (int i = 0; i < NimPlayer.getId(); i++) {
NimPlayer.getPlayer()[i] = null;
System.out.println("Remove all the players");
}
} else {
System.out.print('$');
}*/
//commandin = in.next();
for (int i = 0; i < NimPlayer.getId(); i++) {
String userName = NimPlayer.getPlayer()[i].getUserName().trim();
if (removeUserName != null && userName.equals(removeUserName)) {
NimPlayer.getPlayer()[i] = null;
System.out.println("Remove successfully!");// A test to see if the code runs
} else {
System.out.println("The player does not exist");
}
}
}
if (commandin.equals("editplayer")) {
String inName = in.nextLine();
String[] splittedLine = inName.split(",");
if (splittedLine!=null && splittedLine.length==3) {
String userName = splittedLine[0].trim();
String familyName = splittedLine[1].trim();
String givenName = splittedLine[2].trim();
//System.out.println(userName+","+familyName+","+givenName);//Test if in name in the if loop
for (int i = 0; i < NimPlayer.getId(); i++) {
String userCheck = NimPlayer.getPlayer()[i].getUserName().trim();
if (userName != null && userCheck.equals(userName)) {
NimPlayer.getPlayer()[i].setFamilyName(familyName);
NimPlayer.getPlayer()[i].setGivenName(givenName);
System.out.println("Edit successfully");
} else {
System.out.println("The player does not exist.");
}
}
} else {
System.out.println("Invalid in! Please enter again.");
}
}
if (commandin.equals("displayplayer")) {
for (int i = 0; i < NimPlayer.getId(); i++) {
String userName = NimPlayer.getPlayer()[i].getUserName();
String familyName = NimPlayer.getPlayer()[i].getfamilyName();
String givenName = NimPlayer.getPlayer()[i].getGivenName();
System.out.println(userName+","+familyName+""+givenName);
}
}
if (commandin.equals("startgame")) {
String dataIn = in.nextLine();
String [] data = splitData(dataIn);
//Check if player in the array
if (data.length==4 && data !=null) {
for (int i = 0; i < NimPlayer.getId(); i++) {
for (int j = i + 1; j < NimPlayer.getId(); j++) {
String player1 = NimPlayer.getPlayer()[i].getUserName();
String player2 = NimPlayer.getPlayer()[j].getUserName();
if (player1==null || player2==null) {
System.out.println("One of the players does not exist. Please enter again");
} else {
System.out.println("Data built successfully.Game starts!");
break;
}
}
}
dataIn = in.nextLine();
}
int dataStone = Integer.parseInt(data[0]);
int dataRemoval = Integer.parseInt(data[1]);
}
}}
//username, given name, family name, number of game played, number of games won
public class NimPlayer {
private String userName;
private String familyName;
private String givenName;
static NimPlayer[] playerList = new NimPlayer[10]; // set an array here
static int id;
//define NimPlayer data type
public NimPlayer(String userName,String surName, String givenName) {
this.userName = userName;
this.familyName = surName;
this.givenName = givenName;
}
// create new data using NimPlayer data type
public static void createPlayer(String userName, String familyName, String givenName) {
if (id<10) {
playerList[id++] = new NimPlayer(userName, familyName, givenName);
} else {
System.out.println("Cannot add more players.");
}
}
public static int getId() {
return id;
}
public static NimPlayer [] getPlayer() {
return playerList;
}
public void setUserName(String userName) {
this.userName = userName;
}
public void setFamilyName(String familyName) {
this.familyName = familyName;
}
public void setGivenName(String givenName) {
this.givenName = givenName;
}
public String getUserName() {
return userName;
}
public String getfamilyName() {
return familyName;
}
public String getGivenName() {
return givenName;
}
}
Above are my Nimsys and NimPlayers class. So far, I have a question:
Is it wrong to manipulate the players in the Nimplayer?
Or it is better to create an object in Nimsys if I want to store the record and the times game played?
public class NimGame {
int stoneBalance;
int stars;
public int initializeStone(int startStones) {
stoneBalance = startStones;
return stoneBalance;
}
public void removeStones(int stonesTaken) {
int updatedBalance = stoneBalance - stonesTaken;
stoneBalance = updatedBalance;
}
public void printStar(int star) {
stars = star;
stars = stoneBalance;
for (int stars = 1; stars <= star; stars++) {
System.out.print(" *");
}
System.out.println();
}
Scanner in = new Scanner(System.in);
String playOrNot;
do {
System.out.println("Initial stone count: "+datastone);
System.out.println("Maximum stone removal: "+dataRemoval);
System.out.println("Player 1: "+player1.getUserName());
System.out.println("Player 2: "+player2.getUserName());
// while stoneBalance > 0, two players keep playing the game
while (stoneBalance > 0) {
System.out.print(initialStone + " stones left:");
printStar(initialStone);
// player1's turn and remove the stones; decision of winning
System.out.println(player1 + "'s turn - remove how many?\n");
int takeStone = in.nextInt();
while (takeStone > dataRemoval || takeStone <= 0) {
System.out.println(
"Invalid, you need to remove stones under upper "+
"bound limit or above 0. \n Please enter again.");
takeStone = in.nextInt();
}
removeStones(takeStone); //remove the stone
if (stoneBalance > 0) {
//show the remaining stones
System.out.print(stoneBalance + " stones left:");
printStar(stoneBalance);
} else if (stoneBalance <= 0) {
System.out.println("Game Over\n" + player2 + " wins!\n");
break;
}
// player2's turn and remove the stones; decision of winning
System.out.println(player2 + "'s turn - remove how many?\n");
takeStone = in.nextInt();
while (takeStone > dataRemoval || takeStone <= 0) {
System.out.println(
"Invalid, you need to remove stones under upper " +
"bound limit or above 0. \n Please enter again.");
takeStone = in.nextInt();
}
removeStones(takeStone);
if (stoneBalance > 0) {
System.out.print(stoneBalance + " stones left:");
printStar(stoneBalance);
} else if (stoneBalance <= 0) {
System.out.println("Game Over\n" + player1 + " wins!\n");
break;
}
}
// ask players to play again
in.nextLine();
System.out.println("Do you want to play again (Y/N):");
playOrNot = in.nextLine();
} while (playOrNot.equals("Y"));
}
And this above is my NimGame class. It's the process of the classical Nim game. What should I do to introduce the player? What I did in Nimsys is only to check if players are inside the playerList.
Thanks for taking the time to review my code. Any help is highly appreciated!

On a side note (because it won't affect the execution of the program), the name of an identifier should be self-explanatory e.g. your getPlayer method should be named as getPlayerList as it is returning the playerList, not a single player.
Your logic for startgame should be as follows:
if (commandin.equals("startgame")) {
String dataIn = null, player1 = null, player2 = null;
do {
dataIn = in.nextLine();
String [] data = splitData(dataIn);
//Check if player in the array
if (data !=null && data.length==4) {
NimPlayer[] players = NimPlayer.getPlayerList();
for (int i = 0; i < players.length; i++) {
if(players[i].getUserName().equals(data[2])) {// Checking player1
player1 = players[i].getUserName();
break;
}
}
for (int i = 0; i < players.length; i++) {
if(players[i].getUserName().equals(data[3])) {// Checking player2
player2 = players[i].getUserName();
break;
}
}
}
} while(player1 == null || player2 == null)
//...
}
You can put the repeated code in a function to make your program modular e.g.
String findPlayerByName(String name){
String player = null;
NimPlayer[] players = NimPlayer.getPlayerList();
for (int i = 0; i < players.length; i++) {
if(players[i].getUserName().equals(name)) {
player = players[i].getUserName();
break;
}
}
return player;
}
Then, the logic for startgame will reduce to:
if (commandin.equals("startgame")) {
String dataIn = null, player1 = null, player2 = null;
do {
dataIn = in.nextLine();
String [] data = splitData(dataIn);
//Check if player in the array
if (data !=null && data.length==4) {
player1 = findPlayerByName(data[2]);
player2 = findPlayerByName(data[3]);
}
} while(player1 == null || player2 == null)
//...
}
Another thing I would like you to understand is the problem with the following line:
if (data.length==4 && data !=null)
It should be
if (data !=null && data.length==4)
This way, if data is null, the condition, data.length==4 will not be checked because && operator allows to proceed further only if the condition on its left side evaluates to true.
The problem with your line is that if data is null, you will get the NullPointerException because you will be checking .length on a null reference.
Now, I want two of the players to join the game, and do the following:
Score record
The times the player has played.
Currently, you have userName, familyName, and givenName attributes in NimPlayer class. You need to create two more attributes, private int score and private int numbersOfGamesPlayed with their public getters and setters. You need to use these attributes to store the value of score and the numbers of time a player has played the game.

How to get my FileWriter to find the next available line than write below that

So I have seen alot of similar questions to this one but can't seem to find the answer so sorry if this is a duplicate. So I am creating a java program for black jack that I would like to have a system in place to save the chips the user has. I can get it to work but whenever I try to get it to save it just seems to overwrite what was already previously there.
Example
User enters there name: Bob
The system automatically knows there chips so when they press the button to save game it writes there name and chips like so...
Bob
200 (or however many chips they have)
The problem comes up when a new user enters there name and saves so say sally was saving instead of going
Bob
200
Sally
300
It does
Sally
300
And completly deletes bob
public void newSave(String user){
this.user = user;
user = user;
String Chip = Integer.toString(chips);
try{
FileWriter fileWriter = new FileWriter(file);
fileWriter.write(user);
fileWriter.write("\n");
fileWriter.write(Chip);
fileWriter.close();
}
catch(Exception e){
System.out.println(e.getMessage());
}
}
Here is my code that I have that is where my issue lies.
Here is the whole code of the program method.
import java.util.*;
import java.io.*;
class BlackJackPlayer{
//Keep the data secure by using private
private String hand;
private String user;
private int betNum;
private int sum;
private int numAces;
private int chips = 100;
private String bet;
private static Random gen = new Random();
private String result = "";
public String Win = "Win", Lose = "Lose", Split = "Split";
private final int ACE = 1;
private final int JACK = 11;
private final int QUEEN = 12;
private final int KING = 13;
//Scanner for fileIn
Scanner fileIn;
//File For Saves!
File file = new File("Saves.txt");
//Array For Saves!
private ArrayList<String> User = new ArrayList<>();
private ArrayList<Integer> Chips = new ArrayList<>();
//constructor
public BlackJackPlayer(){
hand = "";
sum = 0;
numAces = 0;
//Create a file if save file does not exist//
try{
if (file.createNewFile()){
System.out.println("Save File Created!");
}
else{
//Say Nothing//
}
}//End Try
catch(Exception e){
System.out.println(e.getMessage());
}
//End File Create//
//Read File //
try{
fileIn = new Scanner(new FileReader(file, true));
while(fileIn.hasNext()){
User.add( fileIn.nextLine().trim() );
Chips.add( fileIn.nextInt() );
}//End While
fileIn.close();
}//End Try
catch(Exception e){
System.out.println(e.getMessage());
}//End Catch
//End Read File//
}//End public
//checkSaveStatus//
//See if save exists already in text than send to proper scenario//
public boolean checkSaveStatus(String user){
for(String u: User){
if (user == u){
return true;
}//end if
}//end for
return false;
}//end checkSaveStatus
//End checkSaveStatus//
//overWriteSave if save already exists//
public void overWriteSave(String user){
}//end overWriteSave
//End overWriteSave//
//newSave scnenario if save dosent exist//
public void newSave(String user){
this.user = user;
user = user;
String Chip = Integer.toString(chips);
try{
FileWriter fileWriter = new FileWriter(file);
fileWriter.write(user);
fileWriter.write("\n");
fileWriter.write(Chip);
fileWriter.close();
}
catch(Exception e){
System.out.println(e.getMessage());
}
}
public boolean checkBet(String bet, int chips){
this.bet = bet;
int betNum = Integer.parseInt(bet);
if(betNum <= chips){
return true;
}
return false;
}
public String setBet(String bet){
this.bet = bet;
betNum = Integer.parseInt(bet);
return "You Bet: " + betNum;
}
public String updateChips(){
chips -= betNum;
return "You have: " + chips + " chips";
}
//Getter for hand variable
public String getHand(){
return hand;
}
public String setHand(){
hand = " ";
return hand;
}
//Getter for sum variable
public int getSum(){
return sum;
}
public void hit(){
//local variable
int currentCard = gen.nextInt(13) + 1;
if(currentCard > ACE && currentCard < JACK){
sum += currentCard;
hand += currentCard + " ";
}
else if(currentCard == ACE){
sum += 11;
numAces++;
hand += "A ";
}
else if(currentCard == QUEEN){
sum += 10;
hand += "Q ";
}
else if(currentCard == QUEEN){
sum += 10;
hand += "Q ";
}
else if(currentCard == KING){
sum += 10;
hand += "K ";
}//Ends Else If
//Is Ace 1 or 11
if(sum > 21 && numAces > 0){
numAces--;
sum -= 10;
}
}//ENDS HIT
public void stand(){
sum = sum;
return;
}//ends stand
public String getWin(BlackJackPlayer other) {
if(sum > 21){
result = Win;
}
else if(sum < other.getSum()){
result = Lose;
}
else if(sum == other.getSum()){
result = Split;
}
return result;
}
}//end class

Use following code.
FileWriter fileWriter = new FileWriter(file, true);
Here true signifies that you want to append data to existing file.
For more details : https://docs.oracle.com/javase/7/docs/api/java/io/FileWriter.html#FileWriter(java.io.File,%20boolean)

Text file load error and array error on mouse island application

I have a problem, I am not looking for answers to my problem I would like some help finding why my array even though specified in main unders switch: case1, case2, case3. I used a for loops with an array that stops at the 5th iteration. However when I run the program it only runs once, am I specifying correctly to make it run 5 times or should it be declared another way? thanks in advance. I should also include there are no errors reported by eclipse at this time until it is ran and only after the first input.
The text files contains
##B##
#---#
#-M-#
#---#
##B##
##B##########
#-----------#
#-----------#
#-----------B
#-----------#
#------M----#
#-----------#
#-----------#
#-----------#
#-----------#
#-----------#
#-----------#
#############
##B#####
#------#
#-M----#
#------#
#------#
#------#
#------#
#####B##
The island maps can be found here
[http://rapidshare.com/share/9704FE33EFF98F1C1E71F6F1DF2DC0D4]
This is the array (int i=0;i<5;i++) however I do not think this is the problem, I can also provide the text files if needed
This is the console out
CS1181 Mouse Island
1. mouseIsland1.txt
2. mouseIsland2.txt
3. mouseIsland3.txt
9. Exit
Please make your selection: 2
Filename: mouseIsland2.txt
Bridge1: 0,0
Bridge2: 0,0
Mouse: 0,0
OUCH! The Mouse fell into the water and died at: 1|1
01
0100000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
0000000000000
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at MouseEscape.runMouseIsland(MouseEscape.java:349)
at MouseEscape.main(MouseEscape.java:71)
End console
import java.io.File;
import java.util.Scanner;
public class MouseEscape {
public static Scanner input = new Scanner(System.in);
public static MouseEscape island1;
public static MouseEscape island2;
public static MouseEscape island3;
private String islandTxt;
private boolean moveDebug;
private int mouseEscaped;
private int mouseDrowned;
private int mouseStarved;
private int islandRows;
private int [] islandCols;
private int runCount;
private int [][] mousePosition;
private int [][] bridgePosition;
private int [][] islandIntArray;
private char [][] islandCharArray;
// main
// Allows the user to select which mouse island map to simulate
public static void main(String[] args) throws Exception
{
System.out.println("CS1181 Mouse Island");
int choice = 0, continueRun = 1;
boolean runResponce = false, correctInput = false;
while (continueRun == 1)
{
System.out.print("\n 1. mouseIsland1.txt"
+ "\n 2. mouseIsland2.txt"
+ "\n 3. mouseIsland3.txt"
+ "\n 9. Exit\n\nPlease make your selection: ");
continueRun = 9;
runResponce = false;
while (correctInput == false){
while (!input.hasNextInt()) {
input.next();
System.out.print("Enter a number 1-3 or 9 to exit.\nPlease make your selection: ");
}
choice = input.nextInt();
if (choice>=1 && choice <=3 || choice == 9){
correctInput = true;
break;
}
}
switch(choice)
{
case 1:
MouseEscape island1 = new MouseEscape("mouseIsland1.txt");
System.out.println("\nFilename: "+island1.getIslandTxt()
+"\nBridge1: "+island1.getBridgePosition(0,0)+","+island1.getBridgePosition(0,1)
+"\nBridge2: "+island1.getBridgePosition(1,0)+","+island1.getBridgePosition(1,1)
+"\nMouse: "+island1.getMousePosition(1,0)+","+island1.getMousePosition(1,1)+"\n");
//island1.drawCharIsland();
for (int i=0;i<5;i++) island1.runMouseIsland();
island1.printIslandStats();
correctInput=false; continueRun=1; break;
case 2:
MouseEscape island2 = new MouseEscape("mouseIsland2.txt");
System.out.println("\nFilename: "+island2.getIslandTxt()
+"\nBridge1: "+island2.getBridgePosition(0,0)+","+island2.getBridgePosition(0,1)
+"\nBridge2: "+island2.getBridgePosition(1,0)+","+island2.getBridgePosition(1,1)
+"\nMouse: "+island2.getMousePosition(1,0)+","+island2.getMousePosition(1,1)+"\n");
//island1.drawCharIsland();
for (int i=0;i<5;i++) island2.runMouseIsland();
island2.printIslandStats();
correctInput=false; continueRun=1; break;
case 3:
MouseEscape island3 = new MouseEscape("mouseIsland3.txt");
System.out.println("\nFilename: "+island3.getIslandTxt()
+"\nBridge1: "+island3.getBridgePosition(0,0)+","+island3.getBridgePosition(0,1)
+"\nBridge2: "+island3.getBridgePosition(1,0)+","+island3.getBridgePosition(1,1)
+"\nMouse: "+island3.getMousePosition(1,0)+","+island3.getMousePosition(1,1)+"\n");
//island1.drawCharIsland();
for (int i=0;i<5;i++) island3.runMouseIsland();
island3.printIslandStats();
correctInput=false; continueRun=1; break;
}
if (runResponce == false)
{
if (continueRun == 1)
{
runResponce = true;
correctInput = false;
}
}
}
input.close();
}
// MouseIslandClass
// Constructs a mouseIslandClass without specifying which mouseIsland to load
public MouseEscape() {
islandTxt = "";
mouseEscaped = 0;
mouseDrowned = 0;
mouseStarved = 0;
islandRows = 0;
runCount = 0;
mousePosition = null;
bridgePosition = null;
islandIntArray = null;
islandCharArray = null;
}
// MouseIslandClass
// Constructs a mouseIslandClass given a mouseIsland map name
public MouseEscape(String _islandTxt) throws Exception{
islandTxt = _islandTxt;
loadIsland();
}
// setIslandTxt
// Sets the mouseIsland filename for the current mouseIsland
public void setIslandTxt(String _islandTxt) throws Exception{
islandTxt = _islandTxt;
}
// getIslandTxt
// Gets the mouseIsland filename for the current mouseIsland
public String getIslandTxt(){
return islandTxt;
}
// getMouseEscaped
// Returns the total number of times a mouse has escaped from the current mouseIsland
public int getMouseEscaped(){
return mouseEscaped;
}
// getMouseDrowned
// Returns the total number of times a mouse has drowned on the current mouseIsland
public int getMouseDrowned(){
return mouseDrowned;
}
// getMouseStarved
// Returns the total number of times a mouse has starved on the current mouseIsland
public int getMouseStarved(){
return mouseStarved;
}
// getBridgePosition
// Returns the coordinate row(x) or column(y) to either of the bridges on the current mouseIsland
public int getBridgePosition(int x, int y){
return bridgePosition[x][y];
}
// getMousePosition
// Returns the coordinate row(x) or column(y) of the mouse on the current mouseIsland
public int getMousePosition(int x, int y){
return mousePosition[x][y];
}
// loadIsland
// Populates any information needed to run the simulation for the current mouseIsland
public void loadIsland() throws Exception{
if (islandTxt == "" || islandTxt == null){
System.out.println("loadIsland() failed! 'islandTxt' variable is empty!");
return;
}
findIslandRow();
findIslandCol();
setCharIslandArray();
findIslandVariables();
}
// printIslandStats
// Prints to the console the statistics for this mouseIsland at its current state
public void printIslandStats(){
System.out.println("Run count: " + runCount + " times\n"
+ "Drowned: " + mouseDrowned + " times\n"
+ "Starved: " + mouseStarved + " times\n"
+ "Escaped: " + mouseEscaped + " times \n");
}
// maxValue
// This function returns the max value of an integer array.
public int maxValue(int [] inArray){
int value = 0;
for (int i=0;i<inArray.length;i++)
if (value<inArray[i]) value = inArray[i];
return value;
}
// findIslandRow
// Counts the number of rows for the current mouseIsland
public void findIslandRow() throws Exception {
Scanner input = new Scanner(new File(islandTxt));
islandRows = 0;
while(input.hasNext()){
input.nextLine();
islandRows++;
}
//System.out.println("Rows: "+islandRows);
input.close();
}
// findIslandCol
// Counts and stores the number of columns for each row in the current mouseIsland
public void findIslandCol() throws Exception {
Scanner input = new Scanner(new File(islandTxt));
String inputLine = ""; int row = 0; islandCols = new int [islandRows];
while(input.hasNext()){
inputLine = input.nextLine();
islandCols[row] = inputLine.length();
//System.out.println("Col"+row+": "+islandCols[row]);
row++;
}
input.close();
}
// loads a mouse island map into a 2 dimensional character array
public void setCharIslandArray() throws Exception {
Scanner input = new Scanner(new File(islandTxt));
islandCharArray = new char [islandRows+1][maxValue(islandCols)+1];
String islandRow ="";
for(int row=0;row<islandRows;row++){
islandRow = input.nextLine();
for (int col=0;col<islandRow.length();col++) {
islandCharArray[row][col] = islandRow.charAt(col);
}
}
input.close();
}
// drawCharIsland
// Draws a character array to the console for testing
public void drawCharIsland() throws Exception{
String ln = "";
for (int row= 0;row<islandRows;row++){
for (int col= 0;col<islandCols[row];col++){
if (col == islandCols[row]-1) ln = "\n"; else ln ="";
System.out.print(islandCharArray[row][col]+ln);
}
}
System.out.println("");
}
// drawIntIsland
// Draws an integer array to the console for testing
public void drawIntIsland() throws Exception{
String ln = "";
for (int row= 0;row<islandRows;row++){
for (int col= 0;col<islandCols[row];col++){
if (col == islandCols[row]-1) ln = "\n"; else ln ="";
System.out.print(islandIntArray[row][col]+ln);
}
}
System.out.println("");
}
// drawBigIntIsland
// Draws an integer array with special formatting for larger numbers the console for testing
public void drawBigIntIsland() throws Exception{
String ln = ""; String rowZero = ""; String colZero = "";
int i=0;
for (int row= 0;row<islandRows;row++){
if (row <= 9) rowZero = " "; else rowZero ="";
for (int col= 0;col<islandCols[row];col++){
if (row == 0)
while (i<islandRows){
if (i == 0) System.out.print("XY");
if (i <= 9) colZero = " "; else colZero ="";
if (i == islandCols[row]-1) ln = "\n"; else ln ="";
System.out.print(colZero+i+ln);
i++;
}
if (col == islandCols[row]-1) ln = "\n"; else ln ="";
if (islandIntArray[row][col] <= 9) colZero = "|"; else colZero ="";
if (col == 0) System.out.print(rowZero+row);
if (row >=0 && col >=0) System.out.print(colZero+islandIntArray[row][col]+ln);
}
}
}
// findIslandVariables
// finds and stores all of the mouseIsland object variables
public void findIslandVariables() throws Exception{
int bCount = 0;
mousePosition = new int [2][2]; bridgePosition = new int [200][2];
for (int row= 0;row<islandRows;row++){
for (int col= 0;col<islandCols[row];col++){
//System.out.println(row+"|"+col);
switch(islandCharArray[row][col]) {
case 'X' : mousePosition[0][0] = row; mousePosition[0][1] = col; //current position
mousePosition[1][0] = row; mousePosition[1][1] = col; //start position
//System.out.println("Mouse found on: "+row+"|"+col);
break;
case '-' :
if (row == 0 || col == 0 || row == islandRows-1 || col == islandCols[row]-1){
bridgePosition[bCount][0] = row; bridgePosition[bCount][1] = col;
bCount++;
//System.out.println("Bridge"+bCount+": "+row+"|"+col);
} else if (col>=islandCols[row-1]-1 || col>=islandCols[row+1]-1){
bridgePosition[bCount][0] = row; bridgePosition[bCount][1] = col;
//System.out.println("Bridge found: "+row+"|"+col);
bCount++;
}
break;
}
}
}
}
// moveMouse
// Computes the movement for the mouse
// set moveDebug to 'true' to display the mouse's moves
public void moveMouse(){
moveDebug = false;
int mouseMove = (int)(Math.random() * 4);
switch(mouseMove){
case 0: mousePosition[0][0]--; if (moveDebug == true) System.out.print("Move: "+mouseMove+"[UP] "); break;
case 1: mousePosition[0][0]++; if (moveDebug == true) System.out.print("Move: "+mouseMove+"[DOWN] "); break;
case 2: mousePosition[0][1]--; if (moveDebug == true) System.out.print("Move: "+mouseMove+"[LEFT] "); break;
case 3: mousePosition[0][1]++; if (moveDebug == true) System.out.print("Move: "+mouseMove+"[RIGHT] "); break;
}
if (moveDebug == true) System.out.println(" Location:|"+mousePosition[0][0]+"|"+mousePosition[0][1]+"|");
}
// runMouseIsland
// Displays the outcome of one trial of the current mouseIsland
public void runMouseIsland() throws Exception{
islandIntArray = new int [islandRows][maxValue(islandCols)];
mousePosition[0][0] = mousePosition [1][0]; mousePosition[0][1] = mousePosition [1][1];
for (int count=0;count<100;count++){
moveMouse();
if (mousePosition[0][0] == bridgePosition[0][0] && mousePosition[0][1] == bridgePosition[0][1] || mousePosition[0][0] == bridgePosition[1][0] && mousePosition[0][1] == bridgePosition[1][1] ){
System.out.println("The mouse has escaped using the bridge at: "+mousePosition[0][0]+"|"+mousePosition[0][1]);
islandIntArray[mousePosition[0][0]][mousePosition[0][1]]++;
mouseEscaped++;
break;
} else
if (islandCharArray[mousePosition[0][0]][mousePosition[0][1]] == '#') {
System.out.println("OUCH! The Mouse fell into the water and died at: "+mousePosition[0][0]+"|"+mousePosition[0][1]);
islandIntArray[mousePosition[0][0]][mousePosition[0][1]]++;
mouseDrowned++;
break;
}
islandIntArray[mousePosition[0][0]][mousePosition[0][1]]++;
if (count == 99){
System.out.println("The mouse withered away (died) at: "+mousePosition[0][0]+"|"+mousePosition[0][1]);
mouseStarved++;
}
}
drawIntIsland();
runCount++;
}
}

Displaying Pictures in Array

In drjava I'm trying to acquire pictures in hold them in the array, and then print out a description of each picture. Right now everything compiles but when I run it has me choose the folder that contains the pictures and then the interactions pane disappears. The code I have so far is in my House app for acquiring the pictures and printing the descriptions is
SSCCEE
HOUSE.java
public class House
{
String owner;
public final static int CAPACITY = 6;
Picture[ ] pictArray = new Picture[CAPACITY];
public House(String pString)
{
this.owner = pString;
}
public String toString()
{
return("The House owned by " + this.owner);
}
public void acquire( int position, Picture pRef )
{
this.pictArray[ position ] = pRef;
}
public void printPictures()
{
for (int i=0; i < this.pictArray.length;i++)
{
System.out.print("The Picture in position " + i + " is ");
System.out.println( this.pictArray[ i ]);
}
}
public void swap( int positionA, int positionB )
{
System.out.println("NOTHING DONE. THIS IS JUST A swap's STUB");
}
public void showOff()
{
System.out.println("NOTHING DONE. THIS IS JUST showOff's STUB");
}
}
Test.java
import java.util.Scanner;
public class Test
{
public static void main(String[] a)
{
House h = new House("Justin Chaisetseree");
Scanner sc = new Scanner(System.in);
FileChooser.pickMediaPath();
for( int i = 0; i < 6; i++)
{
h.acquire(i,new Picture(FileChooser.pickAFile()));
}
h.printPictures();
h.showOff();
Boolean done = false;
while( ! done )
{
System.out.println("Which two do you want to swap?");
System.out.print("Type in two numbers from 0 to ");
System.out.print( 5 );
System.out.println(" or two -1s to stop.");
int userInput1 = sc.nextInt();
int userInput2 = sc.nextInt();
if( userInput1 < 0 || userInput2 < 0)
{
done = true;
}
else
{
h.swap( userInput1, userInput2 );
}
}
h.showOff();
}
}

Infinite while loop in java, not reading in sentinel

I've had this problem throughout multiple programs, but I can't remember how I fixed it last time. In the second while loop in my body, the second sentinel value is never read in for some reason. I've been trying to fix it for a while now, thought I might see if anyone had any clue.
import java.text.DecimalFormat; // imports the decimal format
public class Car {
// Makes three instance variables.
private String make;
private int year;
private double price;
// Makes the an object that formats doubles.
public static DecimalFormat twoDecPl = new DecimalFormat("$0.00");
// Constructor that assigns the instance variables
// to the values that the user made.
public Car(String carMake,int carYear, double carPrice)
{
make = carMake;
year = carYear;
price = carPrice;
}
// Retrieves variable make.
public String getMake()
{
return make;
}
// Retrieves variable year.
public int getYear()
{
return year;
}
// Retrieves variable price.
public double getPrice()
{
return price;
}
// Checks if two objects are equal.
public boolean equals(Car c1, Car c2)
{
boolean b = false;
if(c1.getMake().equals(c2.getMake()) && c1.getPrice() == c2.getPrice() &&
c1.getYear() == c2.getYear())
{
b = true;
return b;
}
else
{
return b;
}
}
// Turns the object into a readable string.
public String toString()
{
return "Description of car:" +
"\n Make : " + make +
"\n Year : " + year +
"\n Price: " + twoDecPl.format(price);
}
}
import java.util.Scanner; // imports a scanner
public class CarSearch {
public static void main(String[] args)
{
// initializes all variables
Scanner scan = new Scanner(System.in);
final int SIZE_ARR = 30;
Car[] carArr = new Car[SIZE_ARR];
final String SENT = "EndDatabase";
String carMake = "";
int carYear = 0;
double carPrice = 0;
int count = 0;
int pos = 0;
final String SECSENT = "EndSearchKeys";
final boolean DEBUG_SW = true;
// Loop that goes through the first list of values.
// It then stores the values in an array, then uses the
// values to make an object.
while(scan.hasNext())
{
if(scan.hasNext())
{
carMake = scan.next();
}
else
{
System.out.println("ERROR - not a String");
System.exit(0);
}
if(carMake.equals(SENT))
{
break;
}
if(scan.hasNextInt())
{
carYear = scan.nextInt();
}
else
{
System.out.println("ERROR - not an int" + count);
System.exit(0);
}
if(scan.hasNextDouble())
{
carPrice = scan.nextDouble();
}
else
{
System.out.println("ERROR - not a double");
System.exit(0);
}
Car car1 = new Car(carMake, carYear, carPrice);
carArr[count] = car1;
count++;
}
// Calls the method debugSwitch to show the debug information.
debugSwitch(carArr, DEBUG_SW, count);
// Calls the method printData to print the database.
printData(carArr, count);
// Loops through the second group of values and stores them in key.
// Then, it searches for a match in the database.
**while(scan.hasNext())**
{
if(scan.hasNext())
{
carMake = scan.next();
}
else
{
System.out.println("ERROR - not a String");
System.exit(0);
}
if(carMake.equals(SECSENT))
{
break;
}
if(scan.hasNextInt())
{
carYear = scan.nextInt();
}
else
{
System.out.println("ERROR - not an int" + count);
System.exit(0);
}
if(scan.hasNextDouble())
{
carPrice = scan.nextDouble();
}
else
{
System.out.println("ERROR - not a double");
System.exit(0);
}
Car key = new Car(carMake, carYear, carPrice);
// Stores the output of seqSearch in pos.
// If the debug switch is on, then it prints these statements.
if(DEBUG_SW == true)
{
System.out.println("Search, make = " + key.getMake());
System.out.println("Search, year = " + key.getYear());
System.out.println("Search, price = " + key.getPrice());
}
System.out.println("key =");
System.out.println(key);
pos = seqSearch(carArr, count, key);
if(pos != -1)
{
System.out.println("This vehicle was found at index = " + pos);
}
else
{
System.out.println("This vehicle was not found in the database.");
}
}
}
// This method prints the database of cars.
private static void printData(Car[] carArr, int count)
{
for(int i = 0; i < count; i++)
{
System.out.println("Description of car:");
System.out.println(carArr[i]);
}
}
// Searches for a match in the database.
private static int seqSearch(Car[] carArr, int count, Car key)
{
for(int i = 0; i < count; i++)
{
boolean b = key.equals(key, carArr[i]);
if(b == true)
{
return i;
}
}
return -1;
}
// Prints debug statements if DEBUG_SW is set to true.
public static void debugSwitch(Car[] carArr, boolean DEBUG_SW, int count)
{
if(DEBUG_SW == true)
{
for(int i = 0; i < count; i++)
{
System.out.println("DB make = " + carArr[i].getMake());
System.out.println("DB year = " + carArr[i].getYear());
System.out.println("DB price = " + carArr[i].getPrice());
}
}
}
}

I think this is your problem, but I might be wrong:
Inside your while loop, you have these calls:
next()
nextInt()
nextDouble()
The problem is that the last call (nextDouble), will not eat the newline. So to fix this issue, you should add an extra nextLine() call at the end of the two loops.
What happens is that the next time you call next(), it will return the newline, instead of the CarMake-thing.