I have information like this:
xxx 0 1 2 ...
Name Fred0 Fred1 Fred2
Stamina 2 6 7
Intel 5 4 1
Heart 4 8 2
Speed 5 3 6
So, I was informed previously that creating a 2D ArrayList to store something like this is "archaic" and was provided with a different way to set my code up. The reason I was using ArrayList<> is because I want to be able to generate new racers as needed, rather than designating an array to a size. If I could just use a simple array this would have been done a week ago. Now I've been screwing with it for a week and I still don't get how it works.
public class test {
public String name;
private int stamina;
private int heart;
private int intel;
private int speed;
public ArrayList<String> racers = new ArrayList<String>();
private void racerInfo(String name) {
this.name = name;
this.stamina = (int) Math.floor(Math.random()*10);
this.heart = (int) Math.floor(Math.random()*10);
this.intel = (int) Math.floor(Math.random()*10);
this.speed = (int) Math.floor(Math.random()*10);
}
public void generate() {
for ( int i=0; i<=10; i++) {
String name = "Fred" + i;
System.out.println(name);
racerInfo(name);
racers.add(name);
}
}
public int getStamina() {
return this.stamina;
}
public int getHeart() {
return this.heart;
}
public int getIntel() {
return this.intel;
}
public int getSpeed() {
return this.speed;
}
}
public class main {
public static test test = new test();
public static void main(String[] args) {
test.generate();
//Put stuff here to pull stamina of Fred2 for example.
}
}
Now, in the main class. How would I do something that should be relatively simple like pulling the Stamina value for Fred2.
I've been following the exact directions I've been given by others here to write most of this code. But at this time, I'm getting to the point of just re-writing it all so that each stat (name, stamina, intel, speed, etc.) is just logged as a separate ArrayList<>. But I can't figure out how to make a 2D ArrayList containing the original ArrayLists ie.
ArrayList<String> name = new ArrayList<String>();
ArrayList<Integer> stamina = new ArrayList<Integer>();
ArrayList<ArrayList<Object>> arrayOfArray = new ArrayList<ArrayList<Object>>();
Yes, I know the arrayOfArray is probably done wrong, but, again, I just get told it's Archaic and nobody'll tell me how I can do it right so I can just go. arrayOfArray.get(2,1) and pull information that I want/need.
Sorry for the information overload here. but I'm trying to just find the best possible solution for what I want to do. If you can tell me how to correctly pull off either way I will be eternally grateful you you and all of your descendants.
First of you should refactor your class test to class Racer, which is a meaningful name and follows the convention to start classnames with an uppercase letter. Furthermore you should add Stamina, Intel, Heart and Speed to the constructor:
public Racer(String name, int stamina, int intel, int heart, int speed) {
this.name = name;
this.stamina = stamina;
this.intel = intel;
this.heart = heart;
this.speed = speed;
}
Now you can create your racer as following:
Racer fred2 = new Racer("Fred2", 7, 1, 2, 6);
You can store your values in a HashMap. HashMap is a collection consisting of key-value pairs. For the key you can use a string (the name of the racer) and as value you take an instance of your class Racer:
HashMap<String, Racer>() racerMap = new HashMap<>();
racerMap.put("Fred2", fred2);
This you can do in a for-loop for all of your racers. Now you can get the racer objects from your HashMap by calling the getMethod and putting the name as parameter in it. This will return an object of class Racer and you can call the getter methods on this object:
racerMap.get("Fred2").getSpeed();
or
racerMap.get("Fred2").getIntel();
Edit: I just saw your generate method. This method should return the HashMap of racers. In your main method you create a new HashMap:
HashMap<String, Racer> racerMap = generate();
Now you can use the map as described above.
Related
I'm new to Java and I'm trying to get my head around constructs, classes and objects. I apologise if any of this seems stupid to you.
I have been tasked with creating an ArrayList to hold items of type Data (my class). using the .add method - I should add a certain number of names and ages then output.
I have sort of done it, but I was wondering if I could use the functions like SetAge and SetAge from my class to use within my ArrayList to create a new person and then output it together like I have with the rest. Is there another way?
Thank you for your help & explanation.
Below is my code;
import java.util.ArrayList;
public class workingOn {
public static void main (String[] args)
{
Data Fred = new Data("Fred", 21);
Data Jo = new Data("Jo", 43);
Data Zoe = new Data("Zoe", 37);
ArrayList<Data> myArray = new ArrayList<Data>();
myArray.add(Fred);
myArray.add(Jo);
myArray.add(Zoe);
for (Data temp : myArray)
{
System.out.println(temp.toString());
}
}
}
Below is my class;
public class Data {
private String name;
private int age;
Data(String n,int a)
{
name = n;
age = a;
}
public String GetName()
{
return(name);
}
public void SetName(String n)
{
name = n;
}
public int GetAge()
{
return(age);
}
public void SetAge(int a)
{
age = a;
}
public void Print()
{
System.out.print(("("+ GetName() ));
System.out.print(",");
System.out.print(GetAge());
System.out.print(") ");
}
//i made this so I don't output the object id
public String toString() {
return (name + ", " + age);
}
}
Going through the comments, I am guessing you want to somehow use the setter methods (setName() and setAge()) for the class that you have designed. The easiest way would be:
Data d = new Data("tempName", 10);
myArray.add(d);
This basically creates an object of type Data and adds it to the arraylist. Let's assume that you want to change the name and age of this person you just added, then you should do this:
myArray.get(myArray.size() - 1).setName("newName");
myArray.get(myArray.size() - 1).setAge(18);
To add some explanation, when you add an object to an arraylist, it always adds in the end. We use size() method to get the number of objects in the Arraylist. Since index starts from 0, we use myArray.size() - 1. We use the .get() method to retrieve the object from the arraylist which takes a number as a parameter and return the object at that index.
Combining these two, we get the object at the last possible index, and call the setName() and setAge() function on it.
Hope this helps.
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I'm looking for some tip on how to do a percentage thing for my game I want all flowers in a range of 1-98 and white/black flowers 99-100 to make it more rarerity thanks for the help :)
public enum FlowerSuit {
WHITE_FLOWERS("white", ":white:", "470419377456414720", 1),
YELLOW_FLOWERS("yellow", ":yellow:", "470419561267855360", 1 ),
RED_FLOWERS("red", ":red:", "470419583250202644", 1),
RAINBOW_FLOWERS("rainbow", ":rainbow:", "470419602841665536", 1),
PASTEL_FLOWERS("pastel", ":pastel:", "470419629450199040", 1),
ORANGE_FLOWERS("orange", ":orange:", "470419647900942366", 1),
BLUE_FLOWERS("blue", ":blue:", "470419688753594368", 1),
BLACK_FLOWERS("black", ":black:", "470419706751352842", 1);
private final String displayName;
private final String emoticon;
private int value;
private final String id;
FlowerSuit(String displayName, String emoticon, String id, int value ) {
this.displayName = displayName;
this.emoticon = emoticon;
this.value = value;
this.id = id;
}
public String getDisplayName() {
return displayName;
}
public String getEmoticon() {
return emoticon;
}
public String getId() {
return id;
}
public int getValue() {
// TODO Auto-generated method stub
return value;
}
}
This is how I'd do it, but it can probably be improved, for starters by using Java 8 streams etc.
public enum FlowerSuit {
WHITE_FLOWERS("white", ":white:", "470419377456414720", 1,3),
YELLOW_FLOWERS("yellow", ":yellow:", "470419561267855360", 1,2),
RED_FLOWERS("red", ":red:", "470419583250202644", 1,2),
RAINBOW_FLOWERS("rainbow", ":rainbow:", "470419602841665536", 1,2),
PASTEL_FLOWERS("pastel", ":pastel:", "470419629450199040", 1,2),
ORANGE_FLOWERS("orange", ":orange:", "470419647900942366", 1,2),
BLUE_FLOWERS("blue", ":blue:", "470419688753594368", 1,2),
BLACK_FLOWERS("black", ":black:", "470419706751352842", 1,1);
private static Random random = new Random();
private final String displayName;
private final String emoticon;
private int value;
private final String id;
private final int freq;
private FlowerSuit(String displayName, String emoticon, String id, int value, int freq ) {
this.displayName = displayName;
this.emoticon = emoticon;
this.value = value;
this.id = id;
this.freq = freq;
}
public String getDisplayName() {return displayName;}
public String getEmoticon() {return emoticon;}
public String getId() {return id;}
public int getValue() {return value;}
/**
* Choose a flower
* white has a 3 in 16 (about a 5:1) chance of being picked
* Black has a 1 in 16 chance, everything else 2/16
* #return
*/
public static FlowerSuit pick() {
//first sum all the chances (currently it's 16)
int sum = 0;
for (FlowerSuit f:FlowerSuit.values()) sum+= f.freq;
//now choose a random number
int r = FlowerSuit.random.nextInt(sum) + 1;
//now find out which flower to pick
sum = 0;
for (FlowerSuit f:FlowerSuit.values()) {
sum += f.freq;
if (r<=sum) return f;
}
//code will never get here
return FlowerSuit.WHITE_FLOWERS;
}
public static void main(final String[] args) throws Exception {
//Test it
Map<FlowerSuit,Integer>count = new HashMap<FlowerSuit,Integer>();
for (int a=0;a<1000000;a++) {
FlowerSuit f = FlowerSuit.pick();
Integer i = (count.get(f)!=null)?count.get(f):new Integer(0);
i = new Integer(i+1);
count.put(f,i);
}
int sum = 0;
for (Map.Entry<FlowerSuit,Integer>e:count.entrySet()) sum+=e.getValue();
float f = Float.valueOf(sum);
for (Map.Entry<FlowerSuit,Integer>e:count.entrySet()) {
System.out.println(e.getKey() + " was chosen " + ((e.getValue() / f) * 100f) + "% of the time");
}
}
}
gives
BLUE_FLOWERS was chosen 12.4986% of the time
PASTEL_FLOWERS was chosen 12.4707% of the time
WHITE_FLOWERS was chosen 18.7365% of the time
BLACK_FLOWERS was chosen 6.2632003% of the time
ORANGE_FLOWERS was chosen 12.4986% of the time
RED_FLOWERS was chosen 12.5241995% of the time
YELLOW_FLOWERS was chosen 12.501401% of the time
RAINBOW_FLOWERS was chosen 12.5068% of the time
You can use a TreeMap to map all of the integers from 0 to 99 to a particular FlowerSuit. Take advantage of the floorEntry method to choose a FlowerSuit for each number. It might look something like this.
public class FlowerChooser {
private static final NavigableMap<Integer, FlowerSuit> FLOWER_SUITS;
private static final Random RANDOMS = new Random();
public FlowerChooser() {
FLOWER_SUITS = new TreeMap<>();
FLOWER_SUITS.put(0, FlowerSuit.RED_FLOWERS);
FLOWER_SUITS.put(14, FlowerSuit.ORANGE_FLOWERS);
FLOWER_SUITS.put(28, FlowerSuit.YELLOW_FLOWERS);
FLOWER_SUITS.put(42, FlowerSuit.GREEN_FLOWERS);
FLOWER_SUITS.put(56, FlowerSuit.BLUE_FLOWERS);
FLOWER_SUITS.put(70, FlowerSuit.INDIGO_FLOWERS);
FLOWER_SUITS.put(84, FlowerSuit.VIOLET_FLOWERS);
FLOWER_SUITS.put(98, FlowerSuit.WHITE_FLOWERS);
FLOWER_SUITS.put(99, FlowerSuit.BLACK_FLOWERS);
}
public FlowerSuit randomFlowerSuit() {
int index = RANDOMS.nextInt(100);
return FLOWER_SUITS.floorEntry(index).getValue();
}
}
Create just one object of this class, then whenever you want a FlowerSuit, call the randomFlowerSuit method.
The randomFlowerSuit method picks a random number from 0 to 99, then finds an appropriate entry in the map. The floorEntry method chooses an entry whose key is less than or equal to the chosen number. This means that numbers from 0 to 13 get mapped to red, 14 to 27 get mapped to orange, and so on. The only number that gets mapped to white is 98, and the only number that gets mapped to black is 99.
No matter what solution you implement, you want to include a frequency measure in your enum. As an example, you can do something like this:
public enum FlowerSuit {
WHITE_FLOWERS("white", ":white:", "470419377456414720", 1, 1),
YELLOW_FLOWERS("yellow", ":yellow:", "470419561267855360", 1, 20),
// More declarations here
// Add this variable
private final int frequency;
// Do just as you did before in the constructor, but with the frequency
FlowerSuit(String displayName, String emoticon, String id, int value, int frequency){
this.frequency = frequency;
// More assignments here
}
public int getFrequency(){
return frequency;
}
// More getters here
}
This addition is critical, and no matter what method you use to weight flower selection, you will want this addition to your FlowerSuit enum.
Now, we can explore a few different ways to perform this selection.
Note 1: I use ThreadLocalRandom for random numbers in a range, which is from java.util.concurrent.ThreadLocalRandom.
Note 2: For each of these, make a single instance of FlowerPicker, and use the pickFlower() method to pick the next flower. This avoid running costly setup code over and over.
Method 1: Bag of Flowers
This method is probably the easiest to implement. It entails creating a list of enums where each is represented frequency times, and then selecting a random entry from this list. It is similar to throwing a bunch of flowers in a bag, shaking it, and then reaching your hand in and grabbing the first flower you touch. Here's the implementation:
public class FlowerPicker(){
private ArrayList<FlowerSuit> bag;
public FlowerPicker(){
// Get all possible FlowerSuits
FlowerSuit[] options = FlowerSuit.values();
// You can use an array here or an array list with a defined length if you know the total of the frequencies
bag = new ArrayList<FlowerSuit>();
// Add each flower from options frequency times
for (FlowerSuit flower : options)
for (int i=0; i<flower.getFrequency(); i++)
bag.add(flower);
}
public FlowerBag pickFlower(){
// Now, select a random flower from this list
int randomIndex = ThreadLocalRandom.current().nextInt(0, bag.size());
return bag.get(randomIndex);
}
}
This method has the advantage of being simple enough to understand very easily. However, it can be inefficient if your frequencies are extremely specific (like if you want a rainbow flower to be returned 499,999,999 times out of 1,000,000,000). Let's move on to the next method.
Note 1: You could make this better by reducing the fractions representing the frequency of being chosen, but I'll leave this to you.
Note 2: You could also make this slightly better by storing identification numbers, not FlowerSuit objects in the bag list.
Method 2: Navigable Map
This method is a little bit more difficult. It uses a [NavigableMap][1], which is an implementation of [TreeMap][2]. This method is fairly similar to the Bag of Flowers method, but it is a little bit more efficient. Put simply, it uses the TreeMap to give each FlowerSuit a range of numbers that can be selected to return that FlowerSuit. Here's a full example:
public class FlowerPicker(){
private NavigableMap<Double, FlowerSuit> map;
public FlowerPicker(){
// Get all possible FlowerSuits
FlowerSuit[] options = FlowerSuit.values();
map = new TreeMap<Double, FlowerSuit>();
int runningTotal = 0;
// Add each flower with the proper range
for (FlowerSuit flower : options){
runningTotal += flower.getFrequency();
map.put(runningTotal, flower);
}
}
public FlowerBag pickFlower(){
// Now, select a random number and get the flower with this number in its range
int randomRange = ThreadLocalRandom.current().nextInt(0, bag.size());
return map.higherEntry(randomRange).getValue();
}
}
This is a solid method, and it scales well for very specific frequencies. If you have a bunch of different types of flowers, it will be slightly worse, but this method is still a good option at large scales. There's one more option though.
Method 3: Enumerated Distribution
This method is really nice because you barely have to do anything. However, it uses [EnumeratedDistribution][3] from Apache Commons. Enumerated Distribution requires a list of pairs of objects and weights. Anyway, lets jump into it:
public class FlowerPicker(){
private EnumeratedDistribution distribution;
public FlowerPicker(){
// Get all possible FlowerSuits
FlowerSuit[] options = FlowerSuit.values();
List<Pair<FlowerSuit, Double>> weights = new List<Pair<FlowerSuit, Double>>();
// Add each flower and weight to the list
for (FlowerSuit flower : options){
weights.add(new Pair(flower, flower.getFrequency()));
// Construct the actual distribution
distribution = new EnumeratedDistribution(weights);
}
public FlowerBag pickFlower(){
// Now, sample the distribution
return distribution.sample();
}
}
This is my favorite method, simply because so much of it is done for you. Many problems like this have been solved, so why not use solutions that always exist? However, there is some value to writing the solution yourself.
In conclusion, each of these methods are perfectly fine to use at your scale, but I would recommend the second or third method.
I am a Java beginner, I have been trying to read a csv file from my computer by using Java and insert the data into a ArrayList.
public class DataRepository {
public void loadFile(){
ArrayList<String> binsGrade = new ArrayList<String>();
try {
Scanner fileScanner = new Scanner(new File("C:\\Users\\Max\\Desktop\\Grade_SampleData.csv"));
while(fileScanner.hasNextLine()){
binsGrade.add(fileScanner.nextLine());
}
fileScanner.close();
System.out.println(binsGrade);
} catch (FileNotFoundException e){
e.printStackTrace();
}
}
}
And below is the result I got:
[name,literature,math,physics,chemistry,biology,history,geology,art,sports, Michael,80,90,82,79,75,70,72,68,95, Amy,85,88,73,79,88,93,90,92,75, Johnson,72,89,81,84,83,72,89,90,82, Bob,80,81,84,89,87,90,71,65,89, Tommy,70,89,79,90,88,73,75,89,91, Rachel,90,91,80,92,87,92,95,97,87, Evonne,78,91,87,88,91,76,74,86,91]
All the records are in one row, but I actually want it to be in separated rows and columns, and for example, when I call name, I can get the value: Michael, Amy, Johson and etc. When I call literature, I can get 80, 85, 72, 80 and etc.Then I can probably use these data to do some calculation, like calculate the average, or get the maximum score and etc.
Although I have been searching online for a while, I still have not figured out the best way to achieve this. Can you please share your ideas if you have one minute? Your help will be really appreciated. Thanks!
If you want to have something implemented quickly, you can follow Srivenu comment and use a Map<String, List<String>>. Each entry of the Map will have the name as the key, and a list of string for all the results. For example to add Michael :
myMap.add("Michael", Arrays.asList({"20", "12", "8", "80"}));
Then create the different methods that will go through this map to compute the average, or find the max, etc
If you want a more oriented object approach I suggest you to create objects that will represent your data. First a result object that will contain two attributes, a string that will be the subject and an int that will be the score.
public class Result {
private String subject;
private int score;
public Result(String s, int i) {
subject = s;
score = i;
}
//Add Setters and Getters
//Add additional method if required
}
Secondly Have a Person object that wil represent someone. It will have two attributes, a String representing the name and a list of Results objects.
public class Person {
private String name;
private List<Result> results;
public Person(String s, List<Result> r) {
name = s;
results = r;
}
//Add getters and setters
//Add additional methods if required
/**
* Example of additional method
* This one will return the score for a given subject
**/
public int getScore(String subject) {
Result r = results.get(subject);
return r.getScore();
}
}
Thirdly, create a GroupOfPerson Class that will contain one attribute, a list of person. Then This class will have methods that will return the average, the max, etc...
public class GroupOfPerson {
private List<Person> persons;
public GroupOfPErson(List<Person> p) {
persons = p;
}
/**
* Example of method.
* This one will return the average score for the given subject
**/
public int getAverageForSubject(String subject) {
int average = 0;
for(Person p : persons) {
average += p.getScore(subject);
}
average /= persons.size();
return average;
}
//Add other methods
}
Finally when reading your CSV file, create the corresponding objects.
So, I'm trying to practice my java skills by applying it to some math homework and making a frequency distribution chart using inheritance. In my head, I envision it as a frequency distribution (parent class = FreqDist) that can have multiple "MyStatClasses" (in the form of the MyStatClass array). Each FreqDist has variables that span across all MyStatClasses which is why I put them in the parent class. However, when I call the MyStatClass constructor, my program gets a StackOverflowError. I think this is because the super(s, i) line calls back to the FreqDist constructor and starts over, causing an infinite loop. Assuming this is the case, how would I fix this?
Ideally, I'd like to access my MyStatClass array and grab values that only apply to that MyStatClass, but I cannot get it to work.
public class FreqDist {
private MyStatClass[] freqClasses;
private double[] dblValuesArray;
private int intNumberOfClasses;
private double dblMax;
private double dblMin;
private int intClassWidth;
public FreqDist(String strValues, int intNumOfClasses) {
System.out.println("This is the beginning of the FreqDist constructor...");
dblValuesArray = getDoubleValues(strValues);
intNumberOfClasses = intNumOfClasses;
dblMin = dblValuesArray[0];
dblMax = dblValuesArray[dblValuesArray.length - 1];
intClassWidth = (int)Math.ceil((dblMax - dblMin) / intNumberOfClasses);
freqClasses = new MyStatClass[intNumberOfClasses];
for (int x = 0; x < freqClasses.length; x++) {
freqClasses[x] = new MyStatClass(strValues, intNumOfClasses);
}
}
public double[] getDoubleValues(String strValues) {
String[] strValuesArray = strValues.trim().split(" ");
dblValuesArray = new double[strValuesArray.length];
for (int x = 0; x < strValuesArray.length; x++) {
dblValuesArray[x] = Double.parseDouble(strValuesArray[x]);
}
Arrays.sort(dblValuesArray);
return dblValuesArray;
}
public int getNumberOfClasses() {
return intNumberOfClasses;
}
public double getMin() {
return dblMin;
}
public double getMax() {
return dblMax;
}
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("What are the values? ");
String values = scan.nextLine();
System.out.print("How many classes? ");
int classes = scan.nextInt();
FreqDist fd = new FreqDist(values, classes);
}
}
public class MyStatClass extends FreqDist {
public MyStatClass(String s, int i) {
super(s, i);
}
}
Ok so this is mostly an issue with a flaw in your design.
From what I understand FreqDist is a class that should contain an array of MyStatClass. You want them to have the same properties so you make MyStatClass extend FreqDist. However when you call FreqDist it MyStatClass which Calls a new MyStatClass over and over and over.
One way to solve this is to create a new class that has the shared properties you want FreqDist and MyStatClass to have, and have those two classes inherit from said class. Then create separate constructors for FreqDist and MyStatClass.
A parent type should never refer to its own subtypes, as yours does. Her the parent initializes subtype instances, which require that each initialize the parent type, which initializes subtype instances, which initialize their parent type, which initializes... KABLOOEY!
I'm writing a program that acts as a 'pocket' where the user is able to enter a kind of coin, such as, a quarter and the amount of quarters it has. I was assigned to do 3 different class, the Coin Class in which the coins and their values can be instatiated from, a Pocket Class, where I have to write a method that can add the coins of the user (basically the method would act like ArrayList .add() ) and the PocketClass tester. I have already written most of the code, but I am stuck as to how I could write the following method:
public void addCoin(String s, int i)
{
// s is type of coin, you are using s to instantiate a Coin and get value
// i is number of coins, you are using i to keep adding value to the totalValue
}
My question is how should I approach this? I am not quite clear on how to create method. Would I use a for-loop in order to keep track of the number of coins? I understand that the addCoin method works a lot like .add() from ArrayList.
Here is the code from my other classes:
public class Coin
{
private final String DOLLAR = "DOLLAR";
private final String QUARTER = "QUARTER";
private final String DIME = "DIME";
private final String NICKEL = "NICKEL";
private final String PENNY = "PENNY";
private int value;
private String coinName;
public Coin(String s,int count)//name of the coin and also the number of the coins you have
{
//Use if or switch statement to identify incoming string and provide value
double value=0;
if(DOLLAR.equalsIgnoreCase(s))
{
value=100.0;
}
else if(QUARTER.equalsIgnoreCase(s))
{
value=25.0;
}
else if(DIME.equalsIgnoreCase(s))
{
value=10.0;
}
else if(NICKEL.equalsIgnoreCase(s))
{
value=5.0;
}
else if(PENNY.equalsIgnoreCase(s))
{
value=1.0;
}
}
public int getValue()
{
return value;
}
}
and how the Pocket class is structured:
public class Pocket
{
private int currentValue;
private int totalValue;
private Coin quarter;
private Coin dime;
private Coin nickle;
private Coin penny;
public Pocket()
{ //Set initial value to zero
totalValue = 0;
currentValue = 0;
}
public void addCoin(String s, int i)
{
// s is type of coin, you are using s to instantiate a Coin and get value
// i is number of coins, you are using i to keep adding value to the totalValue
}
public int getValue()
{
return totalValue;
}
public void printTotal()
{
//print out two different output
}
}
I'm assuming you're adding the addCoin method in the Pocket class.
If you intend to keep track of the number of coins of each type within a Pocket, the simplest way to do so would be to declare a Hashmap that is keyed by the coin type (say, a "quarter" or a "dollar") and valued by the number of coins of that type. An invocation of the addCoin(type, count) method, say addCoin("dollar", 5) can then check if the hashmap already contains a key named "dollar" and if present, increment it's value by count.
I would suggest storing coins in a list so that you can add unlimited number of them.
Example:
class Coin{
//Same as your code....
public Coin(String coinType){
//..Same as your code, but removed number of coins
}
}
public class Pocket
{
private int currentValue;
private int totalValue;
//Create a list of coins to store unlimited number of coins
// A pocket can half 5 dimes
List coins;
public Pocket(){
//Set initial value to zero
totalValue = 0;
currentValue = 0;
coins = new ArrayList<Coin>();
}
/**
* This method will take only one coin at a time
**/
public void addCoin(String s){
Coin c = new Coin(s);
coins.add(c);
totalValue+=c.getValue();
}
/**
* This method will take any number of coins of same type
**/
public void addCoin(String s, int c){
//Add each one to array
for(int i=0;i<c;i++)[
addCoin(s);
}
}
}
I am not in favor of keeping multiple coin values in one Coin object because of the fact it is not a true representation of an object. What does that mean is tomorrow if you want to store other Coin attributes like "Printed Year", "President Picture on the coin" etc, you will have hard time. In my opinion it is better to represent one real world object (one coin here) using one object instance in the program,