I am new to Java. Stack with passing the sum value of PairOfDice class into DiceRollerapp Class, where, depending on the sum, a different message displays. No matter what, sum comes in as 0 in DiceRollerapp. Any help is appreciated greatly.
public class PairOfDice extends Die {
private int sum;
private int d1,d2;
public PairOfDice() {
super();
}
public PairOfDice(int sum){
this.sum=sum;
}
public int getValue1() {
d1=super.getValue();
return d1;
}
public int getValue2() {
d2=super.getValue();
return d2;
}
public int getSum(){
sum=d1+d2;
return sum;
}
public void setSum(int sum){
this.sum=sum;
}
}
And:
public class DiceRollerapp extends PairOfDice{
private int total;
public DiceRollerapp() {
super();
}
public DiceRollerapp(int sum) {
super(sum);
}
public String getMessage() {
total=super.getSum();
if (total == 7) {
System.out.println("CRAPS!");
} else if (total == 12) {
System.out.println("BOX CARS!");
} else if (total == 2) {
System.out.println("SNAKE EYES!");
} else {
System.out.println("");
}
return "";
}
}
The issue is that
public int getSum(){
sum=d1+d2;
return sum;
}
Always recalculates the sum based on d1 and d2. That means you must set them before you call getSum().
public String getMessage() {
super.getValue1(); // <-- sets d1.
super.getValue2(); // <-- sets d2
total=super.getSum(); // <-- adds d1 and d2.
if (total == 7) {
System.out.println("CRAPS!");
} else if (total == 12) {
System.out.println("BOX CARS!");
} else if (total == 2) {
System.out.println("SNAKE EYES!");
} else {
System.out.println("");
}
return "";
}
Related
I am creating a dice rolling application with java. I have a "Die" class that rolls a single die, and a "Dice" class that uses multiple instance variable of "die". However, it only returns 0 for my values. The Die class on its own works and will roll a random number, but I can not figure out how to get multiple rolls in my "Dice" class. Any help is appreciated.
Dice Class
public class Dice {
Die die1=new Die();
Die die2=new Die();
private int die1Value;
private int die2Value;
private int sum;
public Dice() {
die1Value=0;
die2Value=0;
}
public int getDie1Value() {
return die1Value;
}
public int getDie2Value() {
return die2Value;
}
public int getSum() {
return sum;
}
public void roll() {
die1Value=die1.getValue();
die2Value=die2.getValue();
sum=die1Value+die2Value;
}
public void printRoll() {
System.out.println("Die 1: "+die1Value);
System.out.println("Die 2: "+die2Value);
System.out.println("Total: "+sum);
if (sum==7) {
System.out.println("Craps!");
} else if (die1Value==1 && die2Value==1) {
System.out.println("Snake Eyes!");
} else if (die1Value==6 && die2Value==6) {
System.out.println("Box Cars!");
} else {
System.out.println();
}
}
}
Die Class
package a3.ben;
public class Die {
private int value;
public Die() {
}
public void roll() {
value=(int) (Math.random()*6)+1;
}
public int getValue() {
return value;
}
}
You never call die.roll. Try changing the roll method in Dice to include rolling both dice before getting their values.
public void roll() {
die1.roll(); // change the value of both dice
die2.roll();
die1Value = die1.getValue();
die2Value = die2.getValue();
sum = die1Value + die2Value;
}
Also added some spaces around operators like = and + for readability
I am trying to use compareTo method to compare two different names. After running the first attempt the program terminates immediately without returning anything. How can I modify this compareTo method to compare the names (Name n and Name n2) and return the result (-1, 1 or 0)? And obviously a print statement can be added to display (equal, before , or after) for the comparison. Thanks for any assistance.
//First attempt
public class Name implements Comparable<Name> {
private String Name;
public Name(String string) {
// TODO Auto-generated constructor stub
}
public String getName() {
return Name;
}
public int compareTo(Name other) {
if (getName().compareTo(other.getName()) < 0) {
return -1;
} else if (getName().compareTo(other.getName()) > 0) {
return 1;
} else if (getName().equals(other.getName())) {
return 0;
}
return getName().compareTo(other.getName());
}
public static void main(String[] args) {
Name n = new Name("jennifer");
n.getName();
Name n2 = new Name("paul");
n2.getName();
}
}
//second attempt
public class Name implements Comparable<String> {
private String Name;
public String getName() {
return Name;
}
public int compareTo(String other) {
if (getName().compareTo(other.getName()) < 0) {
return -1;
} else if (getName().compareTo(other.getName()) > 0) {
return 1;
} else if (getName().equals(other.getName())) {
return 0;
}
return getName().compareTo(other.getName());
}
public static void main(String[] args) {
String Name = new String("jennifer");
String other = new String("paul");
}
}
//First attempt
public class Name {
public static void main(String[] args) {
String n = new String("jennifer");
String n2 = new String("paul");
if (n.compareTo(n2) < 0) {
System.out.println(n +" is before than " +n2);
} else if (n.compareTo(n2) > 0) {
System.out.println(n +" is after than " +n2);
} else if (n.compareTo(n2) == 0) {
System.out.println(n +" is equals to " +n);
}
}
}
Outoput:
jennifer is before than paul
By the way, check this out because every programming language has its own set of rules and conventions and for variables in Java is like this:
If the name you choose consists of only one word, spell that word in
all lowercase letters. If it consists of more than one word,
capitalize the first letter of each subsequent word.
public class Name implements Comparable<Name> {
private String name;
public Name(String name) {
this.name=name;
}
public String getName() {
return name;
}
public int compareTo(Name other) {
if (getName().compareTo(other.getName()) < 0) {
return -1;
} else if (getName().compareTo(other.getName()) > 0) {
return 1;
} else if (getName().equals(other.getName())) {
return 0;
}
return getName().compareTo(other.getName());
}
public static void main(String[] args) {
Name n = new Name("jennifer");
n.getName();
Name n2 = new Name("paul");
n2.getName();
System.out.println(n.getName());
System.out.println(n2.getName());
System.out.println(n2.compareTo(n));
}
}
OUTPUT :
jennifer
paul
1
I have already made a posting about this program once, but I am once again stuck on a new concept that I am learning (Also as a side note; I am a CS student so please DO NOT simply hand me a solution, for my University has strict code copying rules, thank you.). There are a couple of difficulties I am having with this concept, the main one being that I am having a hard time implementing it to my purposes, despite the textbook examples making perfect sense. So just a quick explanation of what I'm doing:
I have an entity class that takes a Scanner from a driver. My other class then hands off the scanner to a superclass and its two subclasses then inherit that scanner. Each class has different data from the .txt the Scanner read through. Then those three classes send off their data to the entity to do final calculations. And that is where my problem lies, after all the data has been read. I have a method that displays a new output along with a few methods that add data from the super along with its derived classes.EDIT: I simply cannot figure out how to call the instance variable of my subclasses through the super so I can add and calculate the data.
Here are my four classes in the order; Driver, Entity, Super, Subs:
public static final String INPUT_FILE = "baseballTeam.txt";
public static void main(String[] args) {
BaseballTeam team = new BaseballTeam();
Scanner inFile = null;
try {
inFile = new Scanner(new File(INPUT_FILE));
team.loadTeam(inFile);
team.outputTeam();
} catch (FileNotFoundException e) {
System.out.println("File " + INPUT_FILE + " Not Found.");
System.exit(1);
}
}
}
public class BaseballTeam {
private String name;
private Player[] roster = new Player[25];
Player pitcher = new Pitcher();
Player batter = new Batter();
BaseballTeam() {
name = "";
}
public String getName() {
return name;
}
public void setName(String aName) {
name = aName;
}
public void loadTeam(Scanner input) {
name = input.nextLine();
for (int i = 0; i < roster.length; i++) {
if (i <= 9) {
roster[i] = new Pitcher();
}
else if ((i > 9) && (i <= 19)) {
roster[i] = new Batter();
}
else if (i > 19) {
roster[i] = new Player();
}
roster[i].loadData(input);
roster[i].generateDisplayString();
//System.out.println(roster[i].generateDisplayString()); //used sout to test for correct data
}
}
public void outputTeam() {
if ((pitcher instanceof Player) && (batter instanceof Player)) {
for (int i = 0; i < roster.length; i++) {
System.out.println(roster[i].generateDisplayString());
}
}
//How do I go about doing calculates?
public int calculateTeamWins() {
if ((pitcher instanceof ) && (batter instanceof Batter)) {
}
return 0;
}
public int calculateTeamSaves() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public double calculateTeamERA() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public double calculateTeamWHIP() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public double calculateTeamBattingAverage() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public int calculateTeamHomeRuns() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public int calculateTeamRBI() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
public int calculateStolenBases() {
if ((pitcher instanceof Pitcher) && (batter instanceof Batter)) {
}
return 0;
}
}
public class Player {
protected String name;
protected String position;
Player(){
name = "";
position = "";
}
public String getName() {
return name;
}
public void setName(String aName) {
name = aName;
}
public String getPosition() {
return position;
}
public void setPosition(String aPosition) {
position = aPosition;
}
public void loadData(Scanner input){
do {
name = input.nextLine();
} while (name.equals(""));
position = input.next();
//System.out.println(generateDisplayString());
}
public String generateDisplayString(){
return "Name: " + name + ", Position:" + position;
}
}
public class Pitcher extends Player {
private int wins;
private int saves;
private int inningsPitched;
private int earnedRuns;
private int hits;
private int walks;
private double ERA;
private double WHIP;
Pitcher() {
super();
wins = 0;
saves = 0;
inningsPitched = 0;
earnedRuns = 0;
hits = 0;
walks = 0;
}
public int getWins() {
return wins;
}
public void setWins(int aWins) {
wins = aWins;
}
public int getSaves() {
return saves;
}
public void setSaves(int aSaves) {
saves = aSaves;
}
public int getInningsPitched() {
return inningsPitched;
}
public void setInningsPitched(int aInningsPitched) {
inningsPitched = aInningsPitched;
}
public int getEarnedRuns() {
return earnedRuns;
}
public void setEarnedRuns(int aEarnedRuns) {
earnedRuns = aEarnedRuns;
}
public int getHits() {
return hits;
}
public void setHits(int aHits) {
hits = aHits;
}
public int getWalks() {
return walks;
}
public void setWalks(int aWalks) {
walks = aWalks;
}
#Override
public void loadData(Scanner input) {
super.loadData(input);
wins = input.nextInt();
saves = input.nextInt();
inningsPitched = input.nextInt();
earnedRuns = input.nextInt();
hits = input.nextInt();
walks = input.nextInt();
}
#Override
public String generateDisplayString() {
calculateERA();
calculateWHIP();
return String.format(super.generateDisplayString() + ", Wins:%1d, Saves:%1d,"
+ " ERA:%1.2f, WHIP:%1.3f ", wins, saves, ERA, WHIP);
}
public double calculateERA() {
try {
ERA = ((double)(earnedRuns * 9) / inningsPitched);
} catch (ArithmeticException e) {
ERA = 0;
}
return ERA;
}
public double calculateWHIP() {
try {
WHIP = ((double)(walks + hits) / inningsPitched);
} catch (ArithmeticException e) {
WHIP = 0;
}
return WHIP;
}
}
public class Batter extends Player {
private int atBats;
private int hits;
private int homeRuns;
private int rbi;
private int stolenBases;
private double batAvg;
Batter() {
super();
atBats = 0;
hits = 0;
homeRuns = 0;
rbi = 0;
stolenBases = 0;
}
public int getAtBats() {
return atBats;
}
public void setAtBats(int aAtBats) {
atBats = aAtBats;
}
public int getHits() {
return hits;
}
public void setHits(int aHits) {
hits = aHits;
}
public int getHomeRuns() {
return homeRuns;
}
public void setHomeRuns(int aHomeRuns) {
homeRuns = aHomeRuns;
}
public int getRbi() {
return rbi;
}
public void setRbi(int aRbi) {
rbi = aRbi;
}
public int getStolenBases() {
return stolenBases;
}
public void setStolenBases(int aStolenBases) {
stolenBases = aStolenBases;
}
#Override
public void loadData(Scanner input) {
super.loadData(input);
atBats = input.nextInt();
hits = input.nextInt();
homeRuns = input.nextInt();
rbi = input.nextInt();
stolenBases = input.nextInt();
}
#Override
public String generateDisplayString() {
calculateBattingAverage();
return String.format(super.generateDisplayString() +
", Batting Average:%1.3f, Home Runs:%1d, RBI:%1d, Stolen Bases:%1d"
, batAvg, homeRuns, rbi, stolenBases);
}
public double calculateBattingAverage() {
try{
batAvg = ((double)hits/atBats);
} catch (ArithmeticException e){
batAvg = 0;
}
return batAvg;
}
}
Also, its probably easy to tell I'm still fairly new here, because I just ran all my classes together in with the code sample and I can't figure out to add the gaps, so feel free to edit if need be.
The typical usage of instanceof in the type of scenario you're describing would be
if (foo instanceof FooSubclass) {
FooSubclass fooSub = (FooSubclass) foo;
//foo and fooSub now are references to the same object, and you can use fooSub to call methods on the subclass
} else if (foo instanceof OtherSubclass) {
OtherSubclass otherSub = (OtherSubclass) foo;
//you can now use otherSub to call subclass-specific methods on foo
}
This is called "casting" or "explicitly casting" foo to FooSubclass.
the concept to call the methods of your subclasses is called polymorphism.
In your runtime the most specific available method is called provided that the method names are the same.
so you can
Superclass class = new Subclass();
class.method();
and the method provided that overwrites the method in Superclass will be called, even if it's defined in the Subclass.
Sorry for my english, I hope that helps a little bit ;-)
This is my code, my questions is with my deal method, how do I get it to inclement the to a different number every time I call it and also how to create a Boolean method. This is my code, my questions is with my deal method, how do I get it to inclement the to a different number every time I call it and also how to create a Boolean method.
package Card;
import java.util.Random;
/**
*
* #author Mr. Pierre
*/
public class Card {
private int SuitRank;
private int CardRank;
private String cardValue;
//My constructor
public Card()
{
SuitRank=1;
CardRank=2;
}
//My deal method
void dealCard()
{
SuitRank++;
Random randomGenerator = new Random();
int SuitRank = randomGenerator.nextInt(4)+1;
CardRank++;
Random randomGenerator1 = new Random();
int CardRank= randomGenerator1.nextInt(13)+2;
}
//My compare method
public int compare(Card otherCard)
{
if (otherCard.getCardRank() > CardRank)
return 1;
if (otherCard.getCardRank() == CardRank)
{
if (otherCard.getSuitRank() > SuitRank)
return 1;
if (otherCard.getSuitRank()< SuitRank)
return -1;
if (otherCard.getSuitRank()==SuitRank)
return 0;
}
if (otherCard.getCardRank() < CardRank)
return -1;
return CardRank;
}
//my Get suitrank method
public int getSuitRank()
{
SuitRank++;
return SuitRank;
}
public String getSuitName ()
{
String SuitName="";
if( SuitRank == 1){
SuitName = "Clubs";
}
else if(SuitRank == 2){
SuitName = "Diamonds";
}
else if(SuitRank == 3){
SuitName = "Hearts";
}
else if(SuitRank == 4){
SuitName = "Spades";
}
return SuitName;
}
public int getCardRank ()
{
return CardRank;
}
public String getCardName ()
{
String CardName="";
if(CardRank==2){
CardName="Duce";
}
else if(CardRank==3){
CardName="Three";
}
else if(CardRank==3){
CardName="Three";
}
else if(CardRank==4){
CardName="Four";
}
else if(CardRank==5){
CardName="Five";
}
else if(CardRank==6){
CardName="Six";
}
else if(CardRank==7){
CardName="Seven";
}
else if(CardRank==8){
CardName="Eight";
}
else if(CardRank==9){
CardName="Nine";
}
else if(CardRank==10){
CardName="Ten";
}
else if(CardRank==11){
CardName="Jack";
}
else if(CardRank==12){
CardName="Queen";
}
else if(CardRank==13){
CardName="King";
}
else if(CardRank==14){
CardName="Ace";
}
return CardName;
}
public String toString()
{
return getCardName()+ " of " +getSuitName();
}
}
int SuitRank = randomGenerator.nextInt(4)+1;
The int means you're creating a local variable instead of modyfying a class member. Also, why are you calling SuitRank++ if you're planning to set SuitRank to a random value right away? Same applies to CardRank.
As for the Boolean method - it's just public Boolean method(...).
ok so my assignment I'm supposed to write a class that stores a temperature that the user gives and checks it with the set parameters to see if Ethy/Oxygen/Water are either freezing or boiling and then display it at the end which ones will be freezing/boiling at the temperature that they entered. I have the majority of both the class and tester completed but I'm getting several errors on my code. I'm not asking anyone to give me the answer but if you could tell me what I'm doing wrong I would greatly appreciate it. Here is my code for class:
public class FreezingBoilingPoints {
private int temperature;
public FreezingBoilingPoints(int temp) {
temperature = temp;
}
public void setTemperature(int temp) {
temperature = temp;
}
public int getTemperature() {
return temperature;
}
private Boolean isEthylFreezing(int temperature) {
if (temperature <= -173) {
return true;
} else {
return false;
}
}
private Boolean isEthylBoiling(int temperature) {
if (temperature >= 172) {
return true;
} else {
return false;
}
}
private Boolean isOxygenFreezing(int temperature) {
if (temperature <= -362) {
return true;
} else {
return false;
}
}
private Boolean isOxygenBoiling(int temperature) {
if (temperature >= -306) {
return true;
} else {
return false;
}
}
private Boolean isWaterFreezing(int temperature) {
if (temperature <= 32) {
return true;
} else {
return false;
}
}
private Boolean isWaterBoiling(int temperature) {
if (temperature >= 212) {
return true;
} else {
return false;
}
}
public String showTempinfo() {
if (isEthylFreezing()) {
System.out.println("Ethyl will freeze");
}
if (isEthylBoiling()) {
System.out.println("Etheyl will boil");
}
if (isOxygenFreezing()) {
System.out.println("Oxygen will freeze");
}
if (isOxygenBoiling()) {
System.out.println("Oxygen will Boil");
}
if (isWaterFreezing()) {
System.out.println("Water will freeze");
}
if (isWaterBoiling()) {
System.out.println("Water will boil");
}
}
}
and the code for my tester is below:
import java.util.Scanner;
public class FreezingBoilingTester {
public static void main(String[] args) {
int temperature;
FreezingBoilingPoints temp1 = new FreezingBoilingPoints(0);
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a temperature: ");
temperature = scan.nextInt();
System.out.println(showTempinfo());
}
}
1) don't pass the temp inside methods, because you already have this value in member variable.
2) you can change if (condition) then true else false into return (condition) and it will be the same result, just for readability .
3) you should return boolean not Boolean wrapper until you need the wrapper.
public final class FreezingBoilingPoints {
private int temperature;
public FreezingBoilingPoints(int temp) {
temperature = temp;
}
public void setTemperature(int temp) {
temperature = temp;
}
public int getTemperature() {
return temperature;
}
private boolean isEthylFreezing() {
return (temperature <= -173);
}
private boolean isEthylBoiling() {
return (temperature >= 172);
}
private boolean isOxygenFreezing() {
return (temperature <= -362);
}
private boolean isOxygenBoiling() {
return (temperature >= -306);
}
private boolean isWaterFreezing() {
return (temperature <= 32) ;
}
private boolean isWaterBoiling() {
return (temperature >= 212);
}
public String showTempinfo() {
StringBuilder result = new StringBuilder();
if (isEthylFreezing()) {
result.append("Ethyl will freeze");
result.append("\n");
}
if (isEthylBoiling()) {
result.append("Etheyl will boil");
result.append("\n");
}
if (isOxygenFreezing()) {
result.append("Oxygen will freeze");
result.append("\n");
}
if (isOxygenBoiling()) {
result.append("Oxygen will Boil");
result.append("\n");
}
if (isWaterFreezing()) {
result.append("Water will freeze");
result.append("\n");
}
if (isWaterBoiling()) {
result.append("Water will boil");
result.append("\n");
}
return result.toString();
}
}
Main:
import java.util.Scanner;
public class FreezingBoilingTester
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a temperature: ");
int temperature = scan.nextInt();
FreezingBoilingPoints temp1 = new FreezingBoilingPoints(temperature );
System.out.println(temp1.showTempinfo());
}
}
updated:
you can use String concatenation:
String result = "";
if ( condition ) {
result += "new result";
result += "\n";
}
but this is not recommended in term of performance, because each += operation will create another String object in memory holding the new result.
The problem is that your private methods are taking in a temperature and yet, you are not passing one in for your showTempinfo() method. Try removing the input parameters and using the temp set in the class. Also, you need to somehow set the temp before you call showTempinfo().
Hope this helps.
You're not passing the input that the user is giving you into the constructor for your FreezingBoilingPoints class. You're initializing that class with 0 and then asking for a temperature from the user. There's no relationship between the temperature the user provided and the class that you're using to test it.
You need to construct your FreezingBoilingPoints object in your main method, then call showTempinfo() on it. Also, your private calc methods should use the member variable; there's no need to take it as a parameter.
You need to pass the user input, temperature, into your FreezingBoilingPoints constructor. Also, the method showTempInfo() is instance specific. For example, you need to instantiate your object, temp1, by passing the user input with the constructor and then invoke temp1.showTempInfo()
Here we go:
1) All your "is..." methods are expecting for an int parameter, however when you're calling them, you're not passing anything. Remove the int parameter from either the method implementation or the method calls
2) You're missing a closing bracket for the method isWaterBoiling;
3) You marked the method "showTempinfo" as returning String, but you are not returning anything for that method. Either add the return command or remove the "String" from the method signature.
In your showTempinfo(), you try to do isEthylFreezing().
But it can't work ... isEthylFreezing is waiting for an int ... but it gets nothing ...