We Keep Coding

Using indexOf() method for ArrayList of objects

In my program, I have a Vendor class and a Hospital class and store instances of these classes in arraylists called vendors and hospitals. My Vendor class has a string array with names of hospitals that correspond to instances of the Hospital class. I'm trying to find a way to go from the name of the hospital in the string array that is part of the Vendor class, to getting the index value of that hospital for the hospitals arraylist. Apologies if this post doesn't make much sense, I'm very new to coding. Any help would be greatly appreciated.
Edit: Please Ctrl+F with the following to jump to the particular lines of code in question
//check if hospital
Vendor Class
package com.company;
import java.util.Arrays;
import java.util.Scanner;
public class Vendor {
//static variables are the same for all vendor instances
static int numOfHospitals;
static int numOfAppointments;
//non-static variables are specific to one vendor instance
int priorityNum;
String salespersonName;
String vendorCompanyName;
String [] vendorPicks;
String[] vendorSchedule;
public void printVendorSchedule() {
System.out.println(Arrays.toString(vendorSchedule));
}
public void printVendorPicks () {
System.out.println(Arrays.toString(vendorPicks));
}
public String getVendorSchedule (int appointmentSlot) {
return vendorSchedule [appointmentSlot];
}
public String getVendorPick (int currentHospitalPick) {
return vendorPicks[currentHospitalPick];
}
public boolean checkVendorSchedule (int appointmentSlot) {
return ((vendorSchedule[appointmentSlot]).equals("open"));
}
public void setVendorAppointment (int appointmentSlot, String hospitalName) {
vendorSchedule[appointmentSlot] = hospitalName;
}
public Vendor createNewVendor(int priorityNum, int numOfAppointments, int numOfHospitals, String salespersonName, String vendorCompanyName){
this.priorityNum=priorityNum;
this.salespersonName=salespersonName;
this.vendorCompanyName=vendorCompanyName;
this.vendorPicks = new String[numOfHospitals];
this.vendorSchedule = new String[numOfAppointments];
for (int i = 0; i <numOfAppointments; i++) {
this.vendorSchedule[i] = "open";
}
Scanner input = new Scanner(System.in);
Vendor vendorToAdd = new Vendor();
//loop to add vendor's hospital picks
int counter = 0;
while (counter < numOfHospitals) {
System.out.println("Enter the #" +(counter+1) +" hospital for "+salespersonName+". If there are no more hospitals for this vendor, enter Done.");
String placeHolder = input.nextLine();
if (placeHolder.equalsIgnoreCase("done")) {
break;
}
vendorPicks[counter]=placeHolder;
counter++;
}
return vendorToAdd;
}
}
Hospital Class
package com.company;
import java.util.Scanner;
import java.util.Arrays;
import java.util.ArrayList;
public class Hospital {
//static variables here
int numOfAppointments;
int numOfHospitals;
//non-static variables here
String nameHospital;
String nameDirector;
String [] hospitalSchedule;
public void printHospitalSchedule () {
System.out.println(Arrays.toString(hospitalSchedule));
}
public String getHospitalSchedule(int appointmentSlot) {
return hospitalSchedule[appointmentSlot];
}
public boolean checkHospitalSchedule (int appointmentSlot) {
return ((hospitalSchedule[appointmentSlot]).equals("open"));
}
public void setHospitalAppointment (int appointmentSlot, String nameVendor) {
hospitalSchedule[appointmentSlot] = nameVendor;
}
public Hospital createNewHospital(int numOfAppointments, int numOfHospitals,
String nameHospital, String nameDirector) {
Hospital h1 = new Hospital();
this.nameDirector=nameDirector;
this.nameHospital=nameHospital;
this.hospitalSchedule = new String[numOfAppointments];
for (int i=0; i < numOfAppointments; i++) {
hospitalSchedule[i] = "open";
}
return h1;
}
}
Main Class
package com.company;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Locale;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// Inputting #vendors, #hospitals
int vendorCounter=1;
System.out.println("Enter the total number of appointment slots.");
Scanner myScanner = new Scanner(System.in);
int numOfAppointments = Integer.parseInt(myScanner.nextLine());
System.out.println("Enter the total number of hospitals in the draft.");
int numOfHospitals = Integer.parseInt(myScanner.nextLine());
ArrayList<Hospital> hospitals = new ArrayList<Hospital>();
//creating hospitals
int hospitalCounter = 1;
while (hospitalCounter <=numOfHospitals) {
System.out.println("Enter the name of hospital #" + hospitalCounter);
String currentHospitalName = myScanner.nextLine().toLowerCase(Locale.ROOT).trim();
System.out.println("Enter the director's name for " + currentHospitalName + ".");
String currentDirectorName = myScanner.nextLine().toLowerCase(Locale.ROOT).trim();
Hospital h1 = new Hospital();
h1.createNewHospital(numOfAppointments, numOfHospitals, currentHospitalName, currentDirectorName);
hospitals.add(h1);
hospitalCounter++;
}
//creating vendors
ArrayList<Vendor> vendors = new ArrayList<Vendor>();
Scanner myInput = new Scanner(System.in);
while (vendorCounter != 2000){
System.out.println("Are you entering a new vendor? Enter Yes or No");
String isAddingNewVendor;
isAddingNewVendor= myScanner.nextLine();
if (isAddingNewVendor.equalsIgnoreCase("yes"))
{
System.out.println("Enter the name of the salesperson.");
String salespersonName = myInput.nextLine();
System.out.println("Enter the company name for "+salespersonName+".");
String vendorCompanyName = myInput.nextLine();
Vendor v1 = new Vendor();
v1.createNewVendor(vendorCounter, numOfAppointments, numOfHospitals,salespersonName,vendorCompanyName);
vendors.add(v1);
vendorCounter++;
}
else vendorCounter = 2000;
}
/* System.out.println(vendors.get(0).vendorCompanyName);
System.out.println(hospitals.get(0).nameHospital);
System.out.println(vendors.get(0));
vendors.get(0).printVendorSchedule();
vendors.get(0).printVendorPicks();
hospitals.get(0).printHospitalSchedule();
if (vendors.get(0).checkVendorSchedule(0)) {
System.out.println ("This appointment slot is open for the vendor.");
}
if (hospitals.get(0).checkHospitalSchedule(0)) {
System.out.println("This appointment slot is open for the hospital.");
}*/
for (int i = 0; i < numOfHospitals; i++) {
System.out.println("Information for hospital #" + i);
System.out.println("Hospital name: " +hospitals.get(i).nameHospital);
System.out.println("Director's name: " + hospitals.get(i).nameDirector);
System.out.println("The hospital's initial schedule:");
hospitals.get(i).printHospitalSchedule();
}
for (int i = 0; i < vendors.size(); i++) {
System.out.println("Information for vendor #" + i);
System.out.println("Salesperson's name: "+vendors.get(i).salespersonName);
System.out.println("Company name: " + vendors.get(i).vendorCompanyName);
System.out.println("The vendor's hospital choices:");
vendors.get(i).printVendorPicks();
System.out.println("The vendor's initial schedule:");
vendors.get(i).printVendorSchedule();
}
//draft loop logic
int draftRound = 1;
while (draftRound <= numOfAppointments) {
if (draftRound % 2 == 1) {
//insert code for odd-numbered draft rounds here.
//these rounds should start with picker 1, then 2, 3, etc.
int currentVendor = 0; //starts this round with the first vendor
while (currentVendor < vendors.size()){
//this while loop continues running through a single draft round until all vendors get a pick
int currentAppointmentSlot = 0;
int currentVendorPickSlot=0;
while (currentVendorPickSlot < numOfHospitals) { //this loops through a single vendor until all appointments checked or appt assigned
//check if hospital and vendor are both open
String currentHospital = vendors.get(currentVendor).vendorPicks[currentVendorPickSlot];
System.out.println(currentHospital);
int currentHospitalsIndex = hospitals.indexOf(currentHospital); //indexof is returning -1 creating the exceptionoutofbounds
System.out.println("Current hospital index:"+ currentHospitalsIndex);
if ( hospitals.get(currentHospitalsIndex).checkHospitalSchedule(currentAppointmentSlot) != vendors.get(currentVendor).checkVendorSchedule(currentAppointmentSlot)) {
currentAppointmentSlot++;
}
else {
vendors.get(currentVendor).setVendorAppointment(currentVendorPickSlot, hospitals.get(currentHospitalsIndex).nameHospital);
hospitals.get(currentHospitalsIndex).setHospitalAppointment(currentVendorPickSlot, vendors.get(currentVendor).salespersonName);
break; // does this break the loop?
}
}
currentVendor++;
}
draftRound++;
}
if (draftRound % 2 == 0) {
//insert code for even-numbered draft rounds here.
//these rounds should start with the last picker and go down by 1 each turn until 1st picker.
int currentVendor = vendors.size()-1; //starts this draft round with the last vendor
while (currentVendor >= 0) {
//this while loop continues running through a single draft round until all vendors get a pick
int currentAppointmentSlot = 0; //looping through the hospital choices for a single vendor
int currentVendorPickSlot=0;
while (currentVendorPickSlot < numOfHospitals) {
//check if hospital and vendor are both open
String currentHospital = vendors.get(currentVendor).vendorPicks[currentVendorPickSlot];
int currentHospitalsIndex = hospitals.indexOf(currentHospital);
if (hospitals.get(currentHospitalsIndex).checkHospitalSchedule(currentAppointmentSlot) != vendors.get(currentVendor).checkVendorSchedule(currentAppointmentSlot)) {
currentAppointmentSlot++;
//continuing the loop if the appointment slot doesn't work
}
else {
vendors.get(currentVendor).setVendorAppointment(currentAppointmentSlot, hospitals.get(currentHospitalsIndex).nameHospital);
hospitals.get(currentHospitalsIndex).setHospitalAppointment(currentAppointmentSlot, vendors.get(currentVendor).salespersonName);
currentVendor++;
break; // does this break the loop?
}
}
currentVendor++;
}
draftRound++;
}
else break;
}
for (int i = 0; i < numOfHospitals; i++) {
System.out.println("Information for hospital #" + i);
System.out.println("Hospital name: " +hospitals.get(i).nameHospital);
System.out.println("Director's name: " + hospitals.get(i).nameDirector);
System.out.println("The hospital's final schedule:");
hospitals.get(i).printHospitalSchedule();
}
for (int i = 0; i < vendors.size(); i++) {
System.out.println("Information for vendor #" + i);
System.out.println("Salesperson's name: "+vendors.get(i).salespersonName);
System.out.println("Company name: " + vendors.get(i).vendorCompanyName);
System.out.println("The vendor's final schedule:");
vendors.get(i).printVendorSchedule();
}
}}

First using stream we will Iterate through hospitals list,
find out the hospital from the list whose name equals currentHospital name, take out the first result using findFirst.
Since the result may be or may not be available it returns Optional.
So on Optional, we will say if it's (the hospital object which we were looking for) present we will get the hospital out of it using the get method
Optional<Hospital> result = hospitals.stream().filter(h -> h.nameHospital.equals(currentHospital)).findFirst();
if(result.isPresent()){
Hospital hospital = result.get();
}

Need to make a Counter using enum ordinals

I need to make a counter array for a Rock Paper Scissors game but can not figure out how to make user input call the enum, and i need to make the moves for the game a counter for them to be used and compared to.
This is my enum
public enum Moves {
Rock(1),
Paper(2),
Scissors(3),
Lizard(4),
Spock(5), ;
private int countOf = 0;
private int moveVal;
private ArrayList<Moves> movesList = new ArrayList<>();
Moves(int moveVal) {
}
public int getmoveVal() {
return moveVal;
}
public int getCountOf() {
for(Moves moveList : Moves.values()) {
countOf++;
}
return countOf;
}
And this is my class that would call it
public static void main(String[] args) {
RockPaperScissorGame rsg = new RockPaperScissorGame(3);
Moves move[] = Moves.values();
int playerMove = 0;
for(int i = 0; i < move.length; i++) {
}
boolean continueGame = true;
#SuppressWarnings("resource")
Scanner keyboard = new Scanner(System.in);
while(continueGame)
{
System.out.println(rsg.moveChoices());
System.out.println("Enter Move:(1,2,3,4 or 5):");
playerMove = keyboard.nextInt();
rsg.playRound(move);
System.out.printf("AI %s!%n", rsg.getAIOutcome().toString());
System.out.printf("Player %s!%n", rsg.getPlayerOutcome().toString());
System.out.println(rsg.moveOutcome());
System.out.println(rsg.currentScore());
if(rsg.isGameOver())
{
System.out.println(rsg.currentWinTotal());
System.out.println("Do you want to Play Again(1 - Yes , 2 - No):");
int answer = keyboard.nextInt();
if(answer == 2)
{
continueGame = false;
}
else
{
rsg.reset();
}
}
}

You can iterate through values to find a Move matching that moveVal:
public Move fromMoveVal(int moveVal) {
for (Move m : Move.values()) if (m.moveVal == moveVal) return m;
return null;
}

Why do object arrays in my ArrayList fail to retain their values?

I am creating a program in Java to simulate evolution. The way I have it set up, each generation is composed of an array of Organism objects. Each of these arrays is an element in the ArrayList orgGenerations. Each generation, of which there could be any amount before all animals die, can have any amount of Organism objects.
For some reason, in my main loop when the generations are going by, I can have this code without errors, where allOrgs is the Organism array of the current generation and generationNumber is the number generations since the first.
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
printOrgs is a method to display an Organism array, where speed and strength are Organism Field variables:
public void printOrgs(Organism[] list)
{
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
}
Later on, after this loop, when I am trying to retrieve the data to display, I call this very similar code:
printOrgs(orgGenerations.get(0));
This, and every other array in orgGenerations, return a null pointer exception on the print line of the for loop. Why are the Organism objects loosing their values?
Alright, here is all of the code from my main Simulation class. I admit, it might be sort of a mess. The parts that matter are the start and simulator methods. The battle ones are not really applicable to this problem. I think.
import java.awt.FlowLayout;
import java.util.*;
import javax.swing.JFrame;
public class Simulator {
//variables for general keeping track
static Organism[] allOrgs;
static ArrayList<Organism[]> orgGenerations = new ArrayList <Organism[]>();
ArrayList<Integer> battleList = new ArrayList<Integer>();
int deathCount;
boolean done;
boolean runOnce;
//setup
Simulator()
{
done = false;
Scanner asker = new Scanner(System.in);
System.out.println("Input number of organisms for the simulation: ");
int numOfOrgs = asker.nextInt();
asker.close();
Organism[] orgArray = new Organism[numOfOrgs];
for (int i=0; i<numOfOrgs; i++)
{
orgArray[i] = new Organism();
}
allOrgs = orgArray;
}
//graphsOrgs
public void graphOrgs() throws InterruptedException
{
JFrame f = new JFrame("Evolution");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(1000,500);
f.setVisible(true);
Drawer bars = new Drawer();
//System.out.println(orgGenerations.size());
for (int iterator=0;iterator<(orgGenerations.size()-1); iterator++)
{
printOrgs(orgGenerations.get(0));
//The 0 can be any number, no matter what I do it wont work
//System.out.println("first");
f.repaint();
bars.data = orgGenerations.get(iterator);
f.add(bars);
//System.out.println("before");
Thread.sleep(1000);
//System.out.println("end");
}
}
//prints all Orgs and their statistics
public void printOrgs(Organism[] list)
{
System.out.println("Number Of Organisms: " + list.length);
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
System.out.println();
}
//general loop for the organisms lives
public void start(int reproductionTime) throws InterruptedException
{
int generationNumber = 0;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(0));
generationNumber++;
while(true)
{
deathCount = 0;
for(int j=0; j<reproductionTime; j++)
{
battleList.clear();
for(int m=0; m<allOrgs.length; m++)
{
if (allOrgs[m].alive == true)
oneYearBattleCheck(m);
}
battle();
}
reproduction();
if (done == true)
break;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
generationNumber++;
}
printOrgs(orgGenerations.get(2));
}
//Checks if they have to fight this year
private void oneYearBattleCheck(int m)
{
Random chaos = new Random();
int speedMod = chaos.nextInt(((int)Math.ceil(allOrgs[m].speed/5.0))+1);
int speedSign = chaos.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
int speed = speedMod + allOrgs[m].speed;
if (speed <= 0)
speed=1;
Random encounter = new Random();
boolean battle = false;
int try1 =(encounter.nextInt(speed));
int try2 =(encounter.nextInt(speed));
int try3 =(encounter.nextInt(speed));
int try4 =(encounter.nextInt(speed));
if (try1 == 0 || try2 == 0 || try3 == 0 || try4 == 0 )
{
battle = true;
}
if(battle == true)
{
battleList.add(m);
}
}
//Creates the matches and runs the battle
private void battle()
{
Random rand = new Random();
if (battleList.size()%2 == 1)
{
int luckyDuck = rand.nextInt(battleList.size());
battleList.remove(luckyDuck);
}
for(int k=0; k<(battleList.size()-1);)
{
int competitor1 = rand.nextInt(battleList.size());
battleList.remove(competitor1);
int competitor2 = rand.nextInt(battleList.size());
battleList.remove(competitor2);
//Competitor 1 strength
int strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor1].strength/5.0))+1);
int strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp1Strength = strengthMod + allOrgs[competitor1].strength;
//Competitor 2 strength
strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor2].strength/5.0))+1);
strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp2Strength = strengthMod + allOrgs[competitor2].strength;
//Fight!
if (comp1Strength>comp2Strength)
{
allOrgs[competitor1].life ++;
allOrgs[competitor2].life --;
}
else if (comp2Strength>comp1Strength)
{
allOrgs[competitor2].life ++;
allOrgs[competitor1].life --;
}
if (allOrgs[competitor1].life == 0)
{
allOrgs[competitor1].alive = false;
deathCount++;
}
if (allOrgs[competitor2].life == 0)
{
allOrgs[competitor2].alive = false;
deathCount ++ ;
}
}
}
//New organisms
private void reproduction()
{
//System.out.println("Number of deaths: " + deathCount + "\n");
if (deathCount>=(allOrgs.length-2))
{
done = true;
return;
}
ArrayList<Organism> tempOrgs = new ArrayList<Organism>();
Random chooser = new Random();
int count = 0;
while(true)
{
int partner1 = 0;
int partner2 = 0;
boolean partnerIsAlive = false;
boolean unluckyDuck = false;
//choose partner1
while (partnerIsAlive == false)
{
partner1 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner1] != null)
{
if (allOrgs[partner1].alive == true)
{
partnerIsAlive = true;
}
}
}
count++;
//System.out.println("Count 2: " + count);
partnerIsAlive = false;
//choose partner2
while (partnerIsAlive == false)
{
if (count+deathCount == (allOrgs.length))
{
unluckyDuck=true;
break;
}
partner2 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner2] != null)
{
if (allOrgs[partner2].alive == true)
{
partnerIsAlive = true;
}
}
}
if (unluckyDuck == false)
count++;
//System.out.println("count 2: " + count);
if (unluckyDuck == false)
{
int numOfChildren = (chooser.nextInt(4)+1);
for (int d=0; d<numOfChildren; d++)
{
tempOrgs.add(new Organism(allOrgs[partner1].speed, allOrgs[partner2].speed, allOrgs[partner1].strength, allOrgs[partner2].strength ));
}
allOrgs[partner1] = null;
allOrgs[partner2] = null;
}
if (count+deathCount == (allOrgs.length))
{
Arrays.fill(allOrgs, null);
allOrgs = tempOrgs.toArray(new Organism[tempOrgs.size()-1]);
break;
}
//System.out.println(count);
}
}
}
Main method:
public class Runner {
public static void main(String[] args) throws InterruptedException {
Simulator sim = new Simulator();
int lifeSpan = 20;
sim.start(lifeSpan);
sim.graphOrgs();
}
}
Organism class:
import java.util.Random;
public class Organism {
static Random traitGenerator = new Random();
int life;
int speed;
int strength;
boolean alive;
Organism()
{
speed = (traitGenerator.nextInt(49)+1);
strength = (50-speed);
life = 5;
alive = true;
}
Organism(int strength1, int strength2, int speed1, int speed2)
{
Random gen = new Random();
int speedMod = gen.nextInt(((int)Math.ceil((speed1+speed2)/10.0))+1);
int speedSign = gen.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
//System.out.println(speedMod);
int strengthMod = gen.nextInt(((int)Math.ceil((strength1+strength2)/10.0))+1);
int strengthSign = gen.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
//System.out.println(strengthMod);
strength = (((int)((strength1+strength2)/2.0))+ strengthMod);
speed = (((int)((speed1+speed2)/2.0))+ speedMod);
alive = true;
life = 5;
}
}
The problem lies in the graphOrgs class when I try to print to check if it is working in preparation for graphing the results. This is when it returns the error. When I try placing the print code in other places in the Simulator class the same thing occurs, a null pointer error. This happens even if it is just after the for loop where the element has been established.

You have code that sets to null elements in your allOrgs array.
allOrgs[partner1] = null;
allOrgs[partner2] = null;
Your orgGenerations list contains the same allOrgs instance multiple times.
Therefore, when you write allOrgs[partner1] = null, the partner1'th element becomes null in all the list elements of orgGenerations, which is why the print method fails.
You should create a copy of the array (you can use Arrays.copy) each time you add a new generation to the list (and consider also creating copies of the Organism instances, if you want each generation to record the past state of the Organisms and not their final state).

Need help using an ArrayList

It seems that 20 regiments were in a continuous process of formation. The first had 1000 men, the second had 950, the third 900, and so on down to the twentieth regiment, which garrisoned only 50. During each week, 100 men were added to each regiment, and at week's end, the largest regiment was sent off to the front.This lasted for a total of 20 weeks.
For this program I have already managed to print out the original number of men for each regiment. But I am having difficult adding 100 men to each regiment.The adding men must be a method in the army class. I am getting the regiment objects using a .txt file. All this files contains is the names of regiments numbered 1-20.
I currently have no errors my only problem is that I do not know how to add men to my regiment. I have to use the addMen method in the army class which I currently have blank.
public class Regiment {
private String name; //name of regiment
private int regNumber; //regiment number
private int men; // regiment men
public Regiment(int regNumber, String name, int men) {
this.name = name;
this.regNumber = regNumber;
this.men = men;
}
public String getName() {
return name;
}
public int getregNumber() {
return regNumber;
}
public int getMen() {
return men;
}
public int addMen2(int RegNumber) {
int men = 1050 - (regNumber * 50);
return men;
}
}
ArmyDataList:
class ArmyDataList {
public ArrayList<Regiment> list;
public ArmyDataList() {
list = new ArrayList<Regiment>();
}
public void AddToList(Regiment current) {
list.add(current);
}
public void RemoveFromList(Regiment current) {
list.remove(current);
}
public Regiment getLargest() {
if (list.isEmpty()) {
return null;
}
Regiment Reg1 = list.get(0);
for (int i = 1; i < list.size(); i++) {
Regiment current = list.get(i); // get next regiment
// is current regiment > largest
if (current.getMen() > Reg1.getMen()) {
Reg1 = current;
}
}
return Reg1;
}
public void addMen() {
}
public String toString() {
String out
= String.format("%28s%12s%n", "Regiments", " Men")
+ String.format("%12s%n", "Number")
+ String.format("%12s%16s%14s%n", "=======", "===============",
"=========");
for (int i = 0; i < list.size(); i++) {
Regiment regim = list.get(i);
int regNumber = regim.getregNumber();
String name = regim.getName();
int men = regim.addMen2(regNumber);
out = out + String.format("%12s", regNumber)
+ String.format("%16s", name)
+ String.format("%10s", men)
+ "\n";
}
return out + "\n";
}
}
RegimentTest:
public class RegimentTest {
public static void main(String[] args) throws IOException
{
ArmyDataList army = new ArmyDataList();
Scanner fileScan = new Scanner(new File("regiments.txt"));
System.out.println("Report Summary:\n");
while (fileScan.hasNext()) {
String line = fileScan.nextLine();
System.out.println(line);
Scanner in = new Scanner(line) ;
int regNumber = in.nextInt();
String name = in.next();
int men = 0 ; //men is set to 0 only because I havent add the men yet
Regiment adder = new Regiment(regNumber, name, men );
army.AddToList(adder) ;
}
System.out.println(army.toString());
}

Add a setMen(int numberOfMen) method to your Regiment class. Then in your addMen() method, you can do something like this:
public void addMen(){
for(Regiment r : list){ //iterate through the list of regiments
r.setMen(r.getMen() + 100); //add 100 men to each regiment
}
}
The setMen method would look like this:
public void setMen(int numberOfMen){
men = numberOfMen;
}
There is another issue with your toString method, where the regiment's addMen2 method is called - right now you're just printing the number, not initializing the number of men. In the constructor for your Regiment class, replace the line
this.men = men;
with
this.men = addMen2(regNumber);
Then in your toString method, replace
int men = regim.addMen2(regNumber);
with
int men = regim.getMen();
Here is what your main should look like:
public static void main(String[] args) throws IOException{
ArmyDataList army = new ArmyDataList();
Scanner fileScan = new Scanner(new File("regiments.txt"));
System.out.println("Report Summary:\n");
while (fileScan.hasNext()) {
String line = fileScan.nextLine();
System.out.println(line);
Scanner in = new Scanner(line);
int regNumber = in.nextInt();
String name = in.next();
int men = 0 ; //men is set to 0 only because I havent add the men yet
Regiment adder = new Regiment(regNumber, name, men );
army.AddToList(adder);
}
System.out.println(army.toString()); //print out the initial # of men
for(int i = 0; i < 20; i++)
army.addMen();
System.out.println(army.toString()); //print the final # of men
}

in Regiment get rid of method addMen2, and replace it with
public void addMen(int men) {
this.men +=men;
}
then in your army you could have method
public void addMen(int men) {
for(Regiment regiment : list){
regiment.addMen(men);
}
}
that will be simplest solution to add 100 men to each regiment,
other thing is, your toString is bit nasty, regiment should know how meny soldiers it ghas, you shouldnt need additional method to calculate it (reason why i recommend you to trash addMen2 method)
to initiate your Regiment, use constructor. You want to have regiments in sizes 1000, 1950, 1900 etc, do it when you are creating them
while (fileScan.hasNext()) {
String line = fileScan.nextLine();
System.out.println(line);
Scanner in = new Scanner(line) ;
int regNumber = in.nextInt();
String name = in.next();
int men = 1050 - (regNumber * 50);
Regiment adder = new Regiment(regNumber, name, men );
army.AddToList(adder) ;
}

Java help! implementing a 2d array of a certain object, the object has multiple private data types and objects

I'm trying to make a 2d array of an object in java. This object in java has several private variables and methods in it, but won't work. Can someone tell me why and is there a way I can fix this?
This is the exeception I keep getting for each line of code where I try to initialize and iterate through my 2d object.
"Exception in thread "main" java.lang.NullPointerException
at wumpusworld.WumpusWorldGame.main(WumpusWorldGame.java:50)
Java Result: 1"
Here is my main class:
public class WumpusWorldGame {
class Agent {
private boolean safe;
private boolean stench;
private boolean breeze;
public Agent() {
safe = false;
stench = false;
breeze = false;
}
}
/**
* #param args
* the command line arguments
* #throws java.lang.Exception
*/
public static void main(String [] args) {
// WumpusFrame blah =new WumpusFrame();
// blah.setVisible(true);
Scanner input = new Scanner(System.in);
int agentpts = 0;
System.out.println("Welcome to Wumpus World!\n ******************************************** \n");
//ArrayList<ArrayList<WumpusWorld>> woah = new ArrayList<ArrayList<WumpusWorld>>();
for (int i = 0 ; i < 5 ; i++) {
WumpusWorldObject [] [] woah = new WumpusWorldObject [5] [5];
System.out.println( "*********************************\n Please enter the exact coordinates of the wumpus (r and c).");
int wumpusR = input.nextInt();
int wumpusC = input.nextInt();
woah[wumpusR][wumpusC].setPoints(-3000);
woah[wumpusR][wumpusC].setWumpus();
if ((wumpusR <= 5 || wumpusC <= 5) && (wumpusR >= 0 || wumpusC >= 0)) {
woah[wumpusR][wumpusC].setStench();
}
if (wumpusC != 0) {
woah[wumpusR][wumpusC - 1].getStench();
}
if (wumpusR != 0) {
woah[wumpusR - 1][wumpusC].setStench();
}
if (wumpusC != 4) {
woah[wumpusR][wumpusC + 1].setStench();
}
if (wumpusR != 4) {
woah[wumpusR + 1][wumpusC].setStench();
}
System.out.println( "**************************************\n Please enter the exact coordinates of the Gold(r and c).");
int goldR = input.nextInt();
int goldC = input.nextInt();
woah[goldR][goldC].setGold();
System.out.println("***************************************\n How many pits would you like in your wumpus world?");
int numPits = input.nextInt();
for (int k = 0 ; k < numPits ; k++) {
System.out.println("Enter the row location of the pit");
int r = input.nextInt();
System.out.println("Enter the column location of the pit");
int c = input.nextInt();
woah[r][c].setPit();
if ((r <= 4 || c <= 4) && (r >= 0 || c >= 0)) {
woah[r][c].setBreeze();
}
if (c != 0) {
woah[r][c - 1].setBreeze();
}
if (r != 0) {
woah[r - 1][c].setBreeze();
}
if (c != 4) {
woah[r][c + 1].setBreeze();
}
if (r != 4) {
woah[r + 1][c].setBreeze();
}
}
for (int x = 0 ; x < 4 ; x++) {
int j = 0;
while (j < 4) {
agentpts = agentpts + woah[x][j].getPoints();
Agent [] [] k = new Agent [4] [4];
if (woah[x][j].getWumpus() == true) {
agentpts = agentpts + woah[x][j].getPoints();
System.out.println("You just got ate by the wumpus!!! THE HORROR!! Your score is " + agentpts);
}
if (woah[x][j].getStench() == true) {
k[x][j].stench = true;
System.out.println("You smell something funny... smells like old person.");
}
if (woah[x][j].getBreeze() == true) {
k[x][j].breeze = true;
System.out.println("You hear a breeze. yeah");
}
if (woah[x][j].getPit() == true) {
agentpts = agentpts + woah[x][j].getPoints();
System.out.println("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH! you dumb bith, your dead now.");
}
// if breeze or stench, if breeze and stench, if nothing, etc then move.
k[x][j].safe = true;
// if(k[i][j].isSafe()!=true){
// } else { }
}
}
}
}
}
Here is my class object that I'm trying to implement:
package wumpusworld;
/**
*
* #author Jacob
*/
public class WumpusWorldObject {
private boolean stench;
private boolean breeze;
private boolean pit;
private boolean wumpus;
private boolean gold;
private int points;
private boolean safe;
public WumpusWorldObject(){
}
public boolean getPit() {
return pit;
}
public void setPit() {
this.pit = true;
}
public boolean getWumpus() {
return wumpus;
}
public void setWumpus() {
this.wumpus = true;
}
public int getPoints() {
return points;
}
public void setPoints(int points) {
this.points = points;
}
public boolean getStench() {
return stench;
}
public void setStench() {
this.stench = true;
}
public boolean getBreeze() {
return breeze;
}
public void setBreeze() {
this.breeze = true;
}
public boolean getSafe() {
return safe;
}
public void setSafe() {
this.safe = true;
}
public void setGold(){
this.gold=true;
}
}

Creating array doesn't mean it will be automatically filled with new instances of your class. There are many reasons for that, like
which constructor should be used
what data should be passed to this constructor.
This kind of decisions shouldn't be made by compiler, but by programmer, so you need to invoke constructor explicitly.
After creating array iterate over it and fill it with new instances of your class.
for (int i=0; i<yourArray.length; i++)
for (int j=0; j<yourArray[i].length; j++)
yourArray[i][j] = new ...//here you should use constructor

AClass[][] obj = new AClass[50][50];
is not enough, you have to create instances of them like
obj[i][j] = new AClass(...);
In your code the line
woah[wumpusR][wumpusC].setPoints(-3000);
must be after
woah[wumpusR][wumpusC] = new WumpusWorldObject();
.