We Keep Coding

How do I access a record from another procedure?

So I am having an issue where I would like to create a record in one procedure, then alter the attributes of that record using other procedures and functions.
import java.util.Scanner; // Imports scanner utility
import java.util.Random;
import java.lang.Math;
class alienPet
{
public void main (String[] param)
{
// We want to call all of the functions
// and procedures to make an interactive
// alien program for the user.
welcomeMessage();
alienCreation();
System.exit(0);
} // END main
/* ***************************************
* Define a method to obtain the users input
* and start the correct method.
*/
public static String userInput (String message)
{
Scanner scan = new Scanner(System.in);
String inp;
print(message);
inp = scan.nextLine();
return inp;
} // END userInput
/* ***************************************
* Define a method to print messages.
*/
public static void print (String message)
{
System.out.println(message);
return;
} // END print
/* ***************************************
* Define a method to
*/
public static void welcomeMessage ()
{
print("Thank you for playing the pet alien game");
print("In this game, you will have to look after your own alien.");
print("There is multiple aspects to looking after your alien, such as:");
print("Hunger, Behaviour and Thirst.");
print("");
print("When prompted, you can use the following commands:");
print("feed -> Replenishes alien to max hunger level");
print("drink -> Replenished thirst level to max");
print("");
return;
} // END
/* ***************************************
* Define a method to
*/
public void alienCreation ()
{
Alien ufo = new Alien();
ufo.name = userInput("What would you like to name your new alien?");
ufo.hungerRate = ranNum(1, 6);
print("On a scale of 1-6, your alien, " + ufo.name + ", has a hunger rate of " + ufo.hungerRate);
alienBehaviour(ufo.hungerRate);
return;
} // END alienCreation
public void alienBehaviour (int hunger) {
if (hunger <= 2){
print(ufo.name + " is very hungry, and is dangerously angry!!");
String action = userInput("You should feed it as soon as possible. (by typing 'feed')");
if (action.equals("feed")){
feedAlien();
}else if (action.equals("drink")) {
alienDrink();
}else{
print("That is a dangerous decision.");
}
}else if (hunger <= 4) {
print(ufo.name + " is mildly hungry, but is in a calm state.");
String action = userInput("Would you like to take any actions?");
if (action.equals("feed")){
feedAlien();
}else if (action.equals("drink")) {
alienDrink();
}else{
print("Okay.");
}
}else if (hunger <= 6) {
print(ufo.name + " is not hungry and is in a happy state.");
String action = userInput("Would you like to take any actions?");
if (action.equals("feed")){
feedAlien();
}else if (action.equals("drink")) {
alienDrink();
}else{
print("Okay.");
}
}
}
public void feedAlien() {
ufo.hungerRate = 6;
print(ufo.name + "'s hunger level replenished to max level 6.");
print(ufo.name + " is now at a happy level.");
}
public void alienDrink() {
ufo.thirst = 6;
print(ufo.name + "'s thirst level replenished to max level 6.");
}
public static int ranNum(int min, int max){ // A function that generates a random integer wihin a given range.
Random random = new Random();
return random.ints(min,(max+1)).findFirst().getAsInt();
} // END ranNum
} // END class alienPet
class Alien {
String name;
int age = 0;
int hungerRate;
int thirst = 6;
}
Obviously, some of the annotations are incomplete as of this time, but the issue I am having is in the alienBehaviour(), feedAlien() and alienDrink() procedures, I cannot seem to access the record created in the alienCreation() procedure.
The errors are all the same and is as follows:
alienPet.java:84: error: cannot find symbol
print(ufo.name + " is very hungry, and is dangerously angry!!");
^
symbol: variable ufo
location: class alienPet
Now I am new to java, so I'm not sure whether I have to make the record global or something, so any help would be greatly appreciated.

Variables declared inside of a method are called local variables and are likely disposed of when the method finishes executing.
Variables declared outside any function are called instance variables and they can be accessed (used) on any function in the program.
You are looking for an instance Alien ufo variable.
class alienPet{ // It is recommended you use the java naming convention.
Alien myAlien = new Alien();
// alienPet a = new alienPet();
// a.myAlien; // you could potentially do this to get an alien from an alienPet class
void someVoid(){
Alien otherAlien;
}
void errorVoid(){
otherAlien.toString();
// causes an error, the otherAlien variable is never visible to errorVoid as it is a local variable
myAlien.toString(); // OK
}
}
https://www.oracle.com/technetwork/java/codeconventions-135099.html

You're having problems with the scope of your variable. Variables are only valid within the curly braces which they were declared in.
WRONG
public void alienCreation ()
{
Alien ufo = new Alien();
ufo.name = userInput("What would you like to name your new alien?");
ufo.hungerRate = ranNum(1, 6);
print("On a scale of 1-6, your alien, " + ufo.name + ", has a hunger rate of " + ufo.hungerRate);
alienBehaviour(ufo.hungerRate);
return;
} // END alienCreation and of the scope of your variable ufo
RIGHT
class alienPet
{
Alien ufo;
[...]
public void alienCreation ()
{
ufo = new Alien();
ufo.name = userInput("What would you like to name your new alien?");
ufo.hungerRate = ranNum(1, 6);
print("On a scale of 1-6, your alien, " + ufo.name + ", has a hunger rate of " + ufo.hungerRate);
alienBehaviour(ufo.hungerRate);
return;
} // END alienCreation and your variable ufo will be initialized afterwards
}

private method call between classes

trying to get areasConnected to display. As you can see I have attemped (poorly I know) to substitute this method with the nextArea method. Will post the GameWorld class below this one. Please note that I DO NOT want someone to do the work for me, just point me in the right direction.
/**
* Auto Generated Java Class.
*/
import java.util.Scanner;
public class WereWolfenstein2D {
GameWorld gameOne = new GameWorld(true);
private boolean tracing = false;
Scanner sc = new Scanner(System.in);
String input, answer, restart;
int walk, current;
char area;
public void explain() {
System.out.print("You are a hunter, defend the village and capture the Werewolf by shooting it three times. ");
System.out.println("If you get bitten visit the village to be cured. " +
"If you get bitten twice you'll turn." +
"If none of the town folk survive, you lose. " +
"Now choose how what circumstances you're willing to work in.");
}
public void pickDifficulity(){
{
System.out.println("Easy, Normal or Hard?");
input = sc.nextLine();
input = input.toUpperCase();
if (input.equals("EASY")){
System.out.println(Difficulty.EASY);
}
else if (input.equals("NORMAL")) {
System.out.println(Difficulty.NORMAL);
}
else if (input.equals("HARD")) {
System.out.println(Difficulty.HARD);
}
}
}
public void preMove(){
System.out.println("current stats");
// no. of actions until dawn
gameOne.checkForDawn();
// current population
gameOne.getVillagePopulation();
// if they can hear village
gameOne.isVillageNear();
// if not bitten:
gameOne.getShotCount();
// current area no.
gameOne.getCurrentArea();
// number of connecting areas
// gameOne.nextArea(char direction);
//gameOne.areasConnected(int s1, int s2);
// no of times werewolf shot
// no. of bullets left
gameOne.getShotCount();
// if the player can smell the wolf
gameOne.werewolfNear();
}
public void pickMove(){
System.out.print("walk shoot, quit or reset?");
answer = sc.nextLine();
//walk
//if area not connected: alert
//if into village: alert that they are healed
//if containing wolf: altert they are bitten, if already bitten game ends
switch(answer) {
case "walk": System.out.println("Pick a direction to walk in south(s), east(e), north(n), west(w)");
current = gameOne.getCurrentArea(); //current area they are in
char direction = sc.next().charAt(current); //direction they wish to travel
// char area = sc.next().charAt(current);
char area1 = 's';
char area2 = 'e';
char area3 = 'n';
char area4 = 'w';
System.out.println("the area to the south is: " + gameOne.nextArea(area1));
System.out.println("the area to the east is: " + gameOne.nextArea(area2));
System.out.println("the area to the north is: " + gameOne.nextArea(area3));
System.out.println("the area to the west is: " + gameOne.nextArea(area4));
System.out.println(current +"<< >>" + direction);
System.out.println("pick again");
int newcurrent = direction;
direction = sc.next().charAt(newcurrent);
System.out.println(newcurrent + "<< new >>" + direction);
break;
case "shoot":
break;
case "quit": System.out.print("would you like to start again? (yes/no)");
restart = sc.nextLine();
if (restart.equals("yes")) {
gameOne.reset();
}
else {
System.out.println("Thanks for playing");
}
break;
case "reset": //gameOne.reset();
this.pickDifficulity();
break;
}
}
public void play() {
this.explain();
this.pickDifficulity();
this.preMove();
this.pickMove();
// gameOne.reset();
}
public void setTracing(boolean onOff) {
tracing = onOff;
}
public void trace(String message) {
if (tracing) {
System.out.println("WereWolfenstein2D: " + message);
}
}
}
GAMEWORLD CLASS>>>
public class GameWorld {
// Final instance variables
public final int NIGHT_LENGTH = 3; // three actions until dawn arrives (day is instantaneous)
private final int MAX_SHOTS_NEEDED = 3; // successful hits required to subdue werewolf
//This map is _deliberately_ confusing, although it actually a regular layout
private int[] east = {1,2,0,4,5,3,7,8,6}; // areas to east of current location (index)
private int[] west = {2,0,1,5,3,4,8,6,7}; // areas to west of current location (index)
private int[] north = {6,7,8,0,1,2,3,4,5}; // areas to north of current location (index)
private int[] south = {3,4,5,6,7,8,0,1,2}; // areas to south of current location (index)
private int numAreas = south.length; // number of areas in the "world"
// Non-final instance variables
private int currentArea; // current location of player
private int villagePos; // area where the village is located
private int wolfPos; // area where the werewolf can be found
private Difficulty level; // difficulty level of the game
private int villagerCount; // number of villagers remaining
private int stepsUntilDawn; // number of actions until night falls
private boolean isBitten; // is the player currently bitten and in need of treatment?
private int hitsRemaining; // number of shots still needed to subdue the werewolf
private Random generator; // to use for random placement in areas
private boolean tracing; // switch for tracing messages
/**
* Creates a game world for the WereWolfenstein 2D game.
* #param traceOnOff whether or not tracing output should be shown
*/
public GameWorld(boolean traceOnOff) {
trace("GameWorld() starts...");
generator = new Random();
generator.setSeed(101); //this default setting makes the game more predictable, for testing
setTracing(traceOnOff); //this may replace random number generator
trace("...GameWorld() ends");
}
/**
* Returns the number of the current area.
* #return which area number player is within
*/
public int getCurrentArea() {
trace("getCurrentArea() starts... ...and ends with value " + currentArea);
return currentArea;
}
/**
* Returns the number of shot attempts, formatted as "total hits/total required"
* #return the fraction of shots that have hit the werewolf (out of the required number of hits)
*/
public String getShotCount() {
String count; // formatted total
trace("getShotCount() starts...");
count = (MAX_SHOTS_NEEDED - hitsRemaining) + "/" + MAX_SHOTS_NEEDED;
trace("getShotCount() ...ends with value " + count);
return count;
}
/**
* Returns the current number of villagers.
* #return the villager count, >= 0
*/
public int getVillagePopulation() {
return villagerCount;
}
/**
* Returns the number of actions remaining until dawn arrives.
* #return actions remaining until dawn event
*/
public int getActionsUntilNight() {
return stepsUntilDawn;
}
/**
* Randomly determines a unique starting location (currentArea), village
* position (villagePos) and werewolf position (wolfPos).
* #param difficulty - the difficulty level of the game
* #return the starting location (area)
*/
public int newGame(Difficulty difficulty) {
trace("newGame() starts...");
level = difficulty;
//determine village location and initialise villagers and night length
villagePos = generator.nextInt(numAreas);
stepsUntilDawn = NIGHT_LENGTH;
villagerCount = level.getVillagerCount();
// determine player's position
if (level.getPlayerStartsInVillage()) {
//place player in village
currentArea = villagePos;
} else {
//pick a random location for player away from the village
do {
currentArea = generator.nextInt(numAreas);
} while (currentArea == villagePos);
}
trace("player starts at " + currentArea);
// determine werewolf's position
trace("calling resetTargetPosition()");
resetWolfPosition();
// define player's status
trace("player is not bitten");
isBitten = false;
trace("werewolf is not hit");
hitsRemaining = MAX_SHOTS_NEEDED;
trace("...newGame() ends with value " + currentArea);
return currentArea;
}
/** Randomly determines a unique location for werewolf (wolfPos). */
private void resetWolfPosition() {
int pos; // werewolf position
trace("resetWolfPosition() starts...");
pos = generator.nextInt(numAreas);
while (pos == currentArea || pos == villagePos) {
trace("clash detected");
// avoid clash with current location
pos = generator.nextInt(numAreas);
}
wolfPos = pos;
trace("werewolf position is " + wolfPos);
trace("...resetWolfPosition() ends");
}
/**
* Returns the nearness of the werewolf.
* #return Status of werewolf's location
* BITTEN: if player is currently bitten (and delirious)
* NEAR: if werewolf is in a connected area
* FAR: if werewolf is elsewhere
*/
public Result werewolfNear() {
trace("werewolfNear() starts");
if (isBitten) {
trace("werewolfNear(): player is still delirious from a bite so cannot sense nearness of werewolf");
return Result.BITTEN;
}
trace("werewolfNear() returning result of nearnessTo(" + wolfPos + ")");
return nearnessTo(wolfPos);
}
/**
* Returns true if the village is near the player (in an adjacent area),
* false otherwise.
* #return true if the player is near (but not in) the village, false otherwise.
*/
public boolean isVillageNear() {
trace("villageNear() starts and returns result of nearnessTo(" + villagePos + ") == Result.NEAR");
return nearnessTo(villagePos) == Result.NEAR;
}
/**
* Returns the nearness of the player to the nominated area.
* #param area the area (werewolf or village) to assess
* #return Nearness of player to nominated area
* NEAR: if player is adjacent to area
* FAR: if player is not adjacent to the area
*/
private Result nearnessTo(int area) {
Result closeness; // closeness of player to area
trace("nearnessTo() starts...");
if ((east[currentArea] == area) ||
(west[currentArea] == area) ||
(north[currentArea] == area) ||
(south[currentArea] == area))
{
// player is close to area
closeness = Result.NEAR;
trace("area is close");
} else {
// player is not adjacent to area
closeness = Result.FAR;
trace("area is far");
}
trace("...nearnessTo() ends with value " + closeness);
return closeness;
}
/**
* Try to move the player to another area. If the move is not IMPOSSIBLE
* then the number of actions remaining before dawn arrives is decremented.
* #param into the area to try to move into
* #return Result of the movement attempt
* SUCCESS: move was successful (current position changed)
* VILLAGE: move was successful and player has arrived in the village (and is not longer bitten)
* BITTEN: move was successful but player encountered the werewolf
* FAILURE: move was successful but already bitten player encountered the werewolf again
* IMPOSSIBLE: move was impossible (current position not changed)
*/
public Result tryWalk(int into) {
Result result; // outcome of walk attempt
trace("tryWalk() starts...");
if (areasConnected(currentArea, into)) {
trace("move into area " + into );
currentArea = into;
if (currentArea != wolfPos) {
// werewolf not found
trace("werewolf not encountered");
result = Result.SUCCESS;
if (currentArea == villagePos) {
isBitten = false;
result = Result.VILLAGE;
}
} else {
// werewolf encountered
if (isBitten) {
trace("werewolf encountered again");
result = Result.FAILURE;
} else {
// not bitten
trace("werewolf encountered");
result = Result.BITTEN;
isBitten = true;
resetWolfPosition();
}
}
stepsUntilDawn--; //one more action taken
} else { // area not connected
trace("move not possible");
result = Result.IMPOSSIBLE;
}
trace("...tryWalk() ends with value " + result);
return result;
}
/**
* Try to shoot a silver bullet at the werewolf from the current area.
* If the shot is not IMPOSSIBLE then the number of actions remaining
* before dawn arrives is decremented.
* #param into the area to attempt to shoot into
* #return status of attempt
* CAPTURED: werewolf has been subdued and captured
* SUCCESS: werewolf has been hit but is not yet captured
* VILLAGE: the shot went into the village and a villager has died
* FAILURE: werewolf not present
* IMPOSSIBLE: area not connected
*/
public Result shoot(int into) {
Result result; // outcome of shooting attempt
trace("shoot() starts...");
if (areasConnected(currentArea, into)) {
// area connected
trace("shoot into area " + into );
if (into == villagePos) {
result = Result.VILLAGE;
villagerCount--;
trace("shot into village");
} else if (into != wolfPos) {
// not at werewolf location (but at least didn't shoot into the village!)
result = Result.FAILURE;
trace("werewolf not present");
} else {
// at werewolf location
hitsRemaining--;
if (hitsRemaining == 0) {
// last hit required to subdue the werewolf
trace("werewolf subdued and captured");
result = Result.CAPTURED;
} else {
// not the last shot
result = Result.SUCCESS;
if (level.getWolfMovesWhenShot()) {
resetWolfPosition();
}
trace("werewolf found but not yet captured");
}
}
stepsUntilDawn--; //one more action taken
} else {
// not at valid location
result = Result.IMPOSSIBLE;
trace("area not present");
}
trace("...shoot() ends with value " + result);
return result;
}
/**
* Checks if there are no more actions left until dawn arrives. If dawn is
* here then decrements the number of villagers, repositions the werewolf
* and resets the number of actions until dawn arrives again. Returns true
* if dawn occurred, false if it did not.
* #return true if dawn just happened, false if has not yet arrived
*/
public boolean checkForDawn() {
if (stepsUntilDawn == 0) {
if (villagerCount > 0) { //dawn may arrive after shooting the last villager
villagerCount--;
}
stepsUntilDawn = NIGHT_LENGTH;
resetWolfPosition();
return true;
}
return false;
}
/**
* Returns true if areas s1 and s2 are connected, false otherwise.
* Also returns false if either area is an invalid area identifier.
* #param s1 the first area
* #param s2 the second area
* #return true if areas are connected, false otherwise
*/
private boolean areasConnected(int s1, int s2) {
if (Math.min(s1, s2) >= 0 && Math.max(s1, s2) < numAreas) { //valid areas...
//...but are they connected?
return east[s1] == s2 || north[s1] == s2 || west[s1] == s2 || south[s1] == s2;
}
//Either s1 or s2 is not a valid area identifier
return false;
}
/**
* Determine ID number of an adjacent area given its direction from the
* current area.
* #param direction the direction to look (n for north, e for east, s for south, w for west)
* #return number of the area in that direction
* #throws IllegalArgumentException if direction is null
*/
public int nextArea(char direction) {
int nextIs; // area number of area in indicated direction
//Valid values
final char N = 'n', E = 'e', S = 's', W = 'w';
trace("nextArea() starts...");
// examine adjacent areas
switch (direction) {
case N: trace("determining number of area to the north");
nextIs = north[currentArea];
break;
case E: trace("determining number of area to the east");
nextIs = east[currentArea];
break;
case S: trace("determining number of area to the south");
nextIs = south[currentArea];
break;
case W: trace("determining number of area to the west");
nextIs = west[currentArea];
break;
default: throw new IllegalArgumentException("Direction must be one of " + N + ", " + E + ", " + S + " or " + W);
}
trace("...nextArea() ends with value for '" + direction + "' of " + nextIs);
return nextIs;
}
/** Resets all game values. */
public void reset() {
trace("reset() starts...");
// reset all game values
trace("resetting all game values");
newGame(level); //start a new game with the same difficulty
trace("...reset() ends");
}
/**
* Turn tracing messages on or off. If off then it is assumed that
* debugging is not occurring and so a new (unseeded) random number
* generator is created so the game is unpredictable.
* #param shouldTrace indicates if tracing messages should be displayed or not
*/
public void setTracing(boolean shouldTrace) {
if (! shouldTrace) { // not tracing so get an unseeded RNG
generator = new Random();
}
tracing = shouldTrace;
}
/**
* Prints the given tracing message if tracing is enabled.
* #param message the message to be displayed
*/
public void trace(String message) {
if (tracing) {
System.out.println("GameWorld: " + message);
}
}
}

You can use reflection. Actually, it's the only way out if you want to directly access the private methods/fields of an object or a class.

Unfair Candy Distribution

I am completing an assignment and am having a hard time figuring out the logic need to make the program work. I do not want a direct answer but could someone point me in the right direction?
Assignment:
Define a class named UnfairCandyDistributor. An UnfairCandyDistributor object represents a mean big brother who is going to divide a set of candies between himself and his hungry little brother. This will be done unfairly: for every candy given to the sibling, the big brother takes for himself a number of additional candies equal to the younger sibling's total. Each UnfairCandyDistributor object should have the same method:
public void nextCandy()
Each time nextCandy is called, the method prints a message about who gets a candy. Each call to nextCandy produces a single line of output. This time the output is the following:
public class TestCandy2 {
public static void main(String[] args) {
UnfairCandyDistributor mean = new UnfairCandyDistributor();
mean.nextCandy(); // 1 for you.
mean.nextCandy(); // 1 for me.
mean.nextCandy(); // 2 for you.
mean.nextCandy(); // 1 for me.
mean.nextCandy(); // 2 for me.
mean.nextCandy(); // 3 for you.
mean.nextCandy(); // 1 for me.
mean.nextCandy(); // 2 for me.
mean.nextCandy(); // 3 for me.
Here The class I have made so far:
public class UnfairCandyDistributor {
private int you;
private int me;
private int extra;
public void nextCandy()
{
if (you != me || extra != you - 1)
{
me++;
System.out.println(me + " for me");
}
else
{
you++;
System.out.println(you + " for you");
extra = 0;
}
}
}

Can't you just add a boolean variable that tells you who to dole out candy to?
public class UnfairCandyDistributor {
private int you = 0;
private int me = 0;
private boolean candyToMe = false;
public void nextCandy()
{
if (candyToMe)
{
for (int i=0; i<you; i++) {
System.out.println("one for me");
me++;
}
else
{
System.out.println("one for you");
you++;
}
candyToMe = !candyToMe;
}
}
or
public class UnfairCandyDistributor {
private int you = 0;
private int me = 0;
private boolean candyToMe = false;
public void nextCandy()
{
if (candyToMe)
{
System.out.println(you + " for me");
me += you;
}
else
{
System.out.println("1 for you");
you++;
}
candyToMe = !candyToMe;
}
}
..depending on whether you want the candies doled out one at a time or in hand-fulls where appropriate.

Cant find where [Exception in thread "main" java.lang.NullPointerException] Applies

I'm in an intro CS class and I'm writing a program that plays a game. I have the framework classes down but this error occurs when I try to run. It says there is a null point at line 51 in the game method but I can't find where the null point is occurring. Here's the code for the four classes.
public class Pog //THIS IS DONE
{
public static void main (String [] Agrs)
{
PogPlayer human = new PogPlayer( "Human" );
PogPlayer computer = new PogPlayer( "Computer" );
PogGame game = new PogGame ( human, computer );
game.play();
} // method main
} // class Pog
public class PogDice
{
private int die1; // Stores the value (1-6) of die1.
private int die2; // Stores the value (1-6) of die2.
private Random rand;
public PogDice()
{
rand = new Random();
} // default constructor
public int roll()
{
int total = 0;
int turnTotal = 0;
String choice;
Scanner scan;
scan = new Scanner(System.in);
do { die1 = rand.nextInt( 5 )+1;
die2 = rand.nextInt( 5 )+1;
total = die1+die2;
System.out.println("Current score is: " + total + "\nRoll again?");
choice = scan.nextLine();
} while (choice == "yes" && hasDoubleOne() == false);
turnTotal = turnTotal + total;
return turnTotal;
} // method rollDice
public boolean hasDoubleOne()
{
boolean doubleOne = false;
if(die1 == 1 && die2 == 1)
doubleOne = true;
else
doubleOne = false;
return doubleOne;
} // method hasDoubleOne
public String toString()
{
return (die1 + ", " + die2);
} // method toString
} // class PogDice
public class PogGame
{
private PogPlayer human;
private PogPlayer computer;
/**
* PogGame (constructor)
*
* #param PogPlayer (human)
* #param PogPlayer (computer)
*/
public PogGame ( PogPlayer humanArg, PogPlayer computerArg )
{
PogPlayer human = humanArg;
PogPlayer comptuer = computerArg;
} // method PogGame (constructor)
public void play()
{
System.out.println("Hello, Welcome to Pog.\n\n This game takes the user "+
"and puts them agaisnt the computer\n in a dice-based "+
"game. Each player takes turns rolling two dice,\n "+
"with their sum being the total points the "+
"player gets.\n If you roll two 1s you lose all "+
"points that turn.\n You have the option to turn "+
"over the dice at any point\n during your turn to "+
"keep all of your points.\n First one to 21 wins!.\n");
human.getCurrent();
} // method play
} // class pogGame
public class PogPlayer
{
private int current; // Value of the current roll
private int score; // Player's point score.
private PogDice dice; // Player's dice
private String name; // Player's name.
public final int WINNER = 21; // number of points required to win
public PogPlayer ( String nameArg )
{
PogDice dice = new PogDice();
score = 0;
} // method PogPlayer (constructor)
public int getCurrent()
{
int current;
current = dice.roll();
return current;
} // method getCurrent
public PogDice getDice()
{
new PogDice();
return new PogDice();
} // method getDice
public int getScore()
{
score = current + score;
return score;
} // method getScore
public boolean hasWon()
{
boolean win;
if(score == WINNER)
{
win = true;
}
else
win = false;
return win;
} // method hasWon
public boolean rollDice()
{
return false;
} // method rollDice
} // class PogPlayer
I'm pretty sure the error is occurring at the human.getCurrent(); line.

public static void main (String [] Agrs)
{
PogPlayer human = new PogPlayer( "Human" );
PogPlayer computer = new PogPlayer( "Computer" );
PogGame game = new PogGame ( human, computer );
game.play();
} // method main
"human" is a local variable. When you call human.getCurrent() in play, it's a different human. In particular, a null one that hasn't been initialized yet.

The problem is that you don't actually setting the human and computer variables correctly in PogGame class, because in the constructor you're creating a new variable, but the instance variable remains null.
private PogPlayer human;
private PogPlayer computer;
/**
* PogGame (constructor)
*
* #param PogPlayer (human)
* #param PogPlayer (computer)
*/
public PogGame ( PogPlayer humanArg, PogPlayer computerArg )
{
PogPlayer human = humanArg; // human is a new variable rather than the human instance variable
PogPlayer comptuer = computerArg;
}
So when you call human.getCurrent(); here will throw an NPE since human didn't initialized.
so change the code to something like:
public PogGame ( PogPlayer humanArg, PogPlayer computerArg )
{
human = humanArg;
comptuer = computerArg;
}
Same thing goes with dice in PogPlayer constructor, change it to:
public PogPlayer(String nameArg) {
dice = new PogDice();// instead of PogDice dice = new PogDice();
score = 0;
}

Error: Could not find or load main class vehicle.Vehicle

I am still at HelloWorld when it comes to my lack of Java skills. I cannot understand this to save my life. I am working on writing an override method? And am just starting out with the code provided from my school before I even start trying to complete the rest and I am already getting errors that I cannot even begin to think of how to correct. Any help at all would be greatly appreciated. I just want this error to go away so I can create some new ones :)
Here is the code:
public class Vehicle
public static void main (String [] args)}
{
private boolean moving; // whether or not the vehicle
private double speed;
private char bearing;
('N','E','S', or 'W')
public Vehicle(){ // Vehicle class no-arg constructor
moving = false; // assume not moving
speed = 0.0; // not moving
bearing = 'N'; // assume 'N'orth
System.out.println("Created a vehicle (no-arg)");
}
public Vehicle (double initialSpeed) // Vehicle 1-arg constructor
bearing = 'W';
speed = initialSpeed;
if (speed > 0.0)
{
moving = true;
}
System.out.println("Created a vehicle (1-arg)");
public Vehicle (double initialSpeed, char initialBearing) // Vehicle 2-arg constructor
bearing = initialBearing;
speed = initialSpeed;
if (speed > 0.0){
moving = true;
}
System.out.println("Created a vehicle (2-arg)");
public void start(double initialSpeed, char initialBearing){
moving = true;
if (initialSpeed >= 5.0 && initialSpeed <= 20.0){
speed = initialSpeed; // valid expected range
} else if (initialSpeed >= 0.0 && initialSpeed < 5.0){
speed = 5.0; // minimum
} else if (initialSpeed < 0.0){
speed = 0.0; // assume no movement
moving = false;
} else if (initialSpeed > 20.0){
speed = 20.0; // maximum allowed
}
switch(initialBearing){
case 'N':
bearing = initialBearing;
break;
case 'E':
bearing = initialBearing;
break;
case 'S':
bearing = initialBearing;
break;
case 'W':
bearing = initialBearing;
default:
System.out.println("invalid bearing " +
initialBearing +
" set to N"); // additional user notification
bearing = 'N';
}
public double getSpeed() { // get and return current speed in mph
return speed;
}
public void setSpeed(double newSpeed){ // set new speed in mph
speed = newSpeed;
}
/**
*
* #return
*/
public char getBearing(){
return bearing;
}
public void speedUp(double mphSteps, int numSteps){
int counter = 0;
while (counter < numSteps)
speed += mphSteps;
System.out.println("counter= " + counter + ", " +
this.toString());
counter++;
}
public String toString(){
return "From toString(): speed= " + getSpeed() +
" mph and bearing= " + getBearing();
}
}
public class Car extends Vehicle{
private String color;
private int doors;
private double hp;
public Car(String carColor, int numDoors,
double horsePower, double
startingSpeed)
{
super(startingSpeed);
color = carColor;
doors = numDoors;
hp = horsePower;
System.out.println("Created a car");
}
public String getColor()
{
return color;
}
public int getDoors()
{
return doors;
}
public double getHp()
{
return hp;
}
public String toString()
{
return "From Car toString(): color= " + getColor() +
" doors= " + getDoors() +
" hp= " + getHp() +
" speed= " + getSpeed() +
" mph and bearing= " + getBearing();}
}
public class TestCar2
{
public static void main(String[] args)
{
Car myCar2 = new Car("blue", 4, 300., 10.0);
System.out.println(myCar2.toString());
myCar2.speedUp(5.0, 2);
}
}
Please Please and thank you for helping!

public class Vehicle
public static void main (String [] args)} // this is totally wrong
// This not compile at least
{
Actually parenthesis({}) you are using is totally wrong. Following structure should follow you. I am guessing that you are not using IDE to do coding. I suggest you to use IDE to do code.
public class MyClass{
public static void main(String[] args){
// main method
}
// some other method
}

Firstly You cannot have two public classes in a single file!!
Secondly you braces are completely unmatching.
public class Vehicle
public static void main (String [] args)}
{
Class has it's own scope and main() function has it's own. So change your code to
public class Vehicle {
public static void main (String [] args) { //your code}
}
your multiple arg constructors don't have proper brackets.
public Vehicle (double initialSpeed) // Vehicle 1-arg constructor
bearing = 'W';
speed = initialSpeed;
if (speed > 0.0)
{
moving = true;
}
System.out.println("Created a vehicle (1-arg)");
change it to
public Vehicle (double initialSpeed) { // Vehicle 1-arg constructor
bearing = 'W';
speed = initialSpeed;
if (speed > 0.0)
{
moving = true;
}
System.out.println("Created a vehicle (1-arg)");
}
lastly your switch statement you need to put break in all cases(except default)
change
case 'W':
bearing = initialBearing;
to
case 'W':
bearing = initialBearing;
break;
If you are new to java and learning basics I suggest use an IDE like Eclipse, Netbeans or Intellij IDEA. Google them to find more info.