Making Bunch Of Tree Trunks - How To Delete Entire Array Of Objects
Jul 30, 2014
I am trying to delete entire set of objects from my graphics program. Specifically I am trying to make a bunch of tree trunks, 10 in total, and then delete them all by pressing a button. I can manage to make the trunks but I can only delete one of them.
Below I can walk you through some of my code step by step to show you what I am trying to do:
Java Code:
public void drawTrunk(double width, double height, double xpos, double ypos) {
trunks = new ArrayList(10);
trunk = new GRect(width / 15.0, height / 3.0);
trunk.setFilled(true);
trunk.setFillColor(Color.orange);
[Code] .....
So basically I just would like to know how to make this work?
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Oct 4, 2014
Iva tried flipping the entire code upside down (expression) and No matter what I do the delete function returns a null pointer exception after my while loops takes the pointer right to where it should be.
package bp;
import java.time.LocalDate;
public class BinaryTree implements IBinaryTree {
private Node root = null;
private int sizeOfTree = 0;
[Code] ....
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Feb 7, 2015
I am passing input from the user to a method that will initialize an array of the data (scores in this case). The method is filling the entire array with the last input value.
array initializer method
Java Code:
public static float[] inputAllScores(float validScore) {
float[] diverScores = new float[7];
for (int i = 0; i < diverScores.length; i++) {
diverScores[i] = validScore;
}
return diverScores;
} mh_sh_highlight_all('java');
[Code] .....
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Oct 22, 2014
I am using libgdx and box2d to try to make a simple cannon game.
When I have the cannonball collide with another object I want to delete that object and have it stop calling all of it's functions. It doesn't seem like I can have it delete itself, and the contactListener has a reference to the cannonball and other object, but if I set either to null, it seems the original reference still exists and the object isn't deleted.
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Oct 10, 2014
I have a question about how to delete only a certain amount of objects on screen in a graphics window. I have a method that will enable me to get rid of every object of the same type off screen, for example this method:
Java Code:
public void deleteTrees() {
//clears all tree trunks and leaves
for (Iterator<GRect> it = historyT.iterator(); it.hasNext();) {
GObject gobj = it.next();
this.remove(gobj);
[Code] ....
That Will delete all trees.
Now In my main method I populate the screen with trees by doing this
Java Code:
for (int xpos = 10; xpos < getWidth() - 40; xpos += getWidth() / 8) {
drawTree(150, 200, xpos, getHeight() / 2.0 - 50);
historyT.add(trunk);
historyL.add(leave);
} mh_sh_highlight_all('java');
My question is how to specify only deleting x amount of trees instead of the whole thing. I pretty sure I need to use something like history.remove(trunk) and to iterate through the amount of trees specified, but not sure how to implement that.
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Apr 5, 2014
I have an assignment on sorting, i kno i can get the sorting down but im having an issue with inputing the 512 ints in a file into an array. the instructor provided us with a file with 4 equal sets of ints. i tried to make my array of size [scan.nextInt()] and it cuts off the last 21 ints. and skips the first int. how can i get all of the integers in the text file into my array? this is what i have so far. if i hard code the array to size 50000 and then try to print the array it compiles but errors out when running it.
System.out.println("Please Enter text file in this format, XXXXX.txt :");
String file =fileName.nextLine();
Scanner scan = new Scanner(new File(file));
int [] data = new int[scan.nextInt()]; <-------here it skips first int
int count= data.length;
for (int i=0; i<data.length-1;i++) {
data[i]=scan.nextInt();
}
System.out.print(Arrays.toString(data));
rst 4 ints in output are: 501, 257, 390, 478...., supposed to be 492,501,390....and last ints are: ....88, 83, 79, 0 and supposed to be :88 83 79 77 76 72 71 71 66 57 56 48 48 41 33 30 23 23 18 17 15 13 9....it replace last ints with 0. why ? and how do i fix this. attached it the text file
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Feb 24, 2013
I am using eclipse 6.0 - structs 1.3my requirement is to simple. "bunch of db data need to display over the table". I need an example.
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May 22, 2014
How to modify and delete data from a array list in net-beans?
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Oct 2, 2014
I need to be able to call this method and it should take the object and, add it to my list of items, but I am having trouble getting it to work. I know the numbers and stuff aren't correct eventually it will add one to the array length when i call add item, but I am just trying to go one step at a time
//creates new MediaItem object and add it to items[]
void addNewItem(String title){
MediaItem object = new MediaItem(title);
MediaItem[] items = new MediaItem[1];
items[0] = ("object.getTitle()");
numberOfItems = numberOfItems + 1;
System.out.println(items[0]);
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Apr 18, 2015
Here is the code: I believe the issue is in the nest for loop with I use
f1.length
But I want to not use the individual sizes I put in, something more suitable so I don't have to change the the values everywhere I may need to.
public class ForestFireDemo {
public static void main(String[] args) {
Forest[][] f1;
f1 = new Forest[10][5];
for(int i =0 ; i < f1.length; i++) {
[Code] ....
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May 31, 2014
I never used tree, node etc. Consider an array of strings that come from html tags. This needs to be turned into a tree structure. Here, any Hn is the child of the most recent Hn-1
String[] Headers = {"H1", "H1", "H2", "H3", "H3", "H2", "H2", "H3",
"H4", "H2", "H2", "H2", "H1", "H2", "H2", "H3", "H4", "H4", "H2" };
Desired output -
ROOT
H1
H1
...H2
......H3
......H3
...H2
...H2
......H3
.........H4
...H2
...H2
...H2
H1
...H2
...H2
......H3
.........H4
.........H4
...H2
ANSWER -
class Example {
static class Node {
final String name;
final int indent;
Collection<Node> children = new LinkedList<> ();
[Code] .....
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Jul 13, 2014
I'm trying to build a binary tree using two arrays I'm given, one is inorder and the other is postorder and I have to construct the tree based on that. I understand the strategy I need to use- the last element of the postorder array tells me the root node, and wherever the value of that node occurs in the inorder array is where the tree is split. I can then apply this idea recursively to build the tree. For whatever reason though, I keep getting stack overflows.
Here's what I have so far:
public static class TreeNode {
char val;
TreeNode left;
TreeNode right;
TreeNode(char newVal) {
val = newVal;
[Code] .....
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Jun 17, 2014
How to do draw the original binary tree based on traversal results?
A binary tree has this pre-order traversal result: A,B,D,H,I,E,F,C,G,K,J (TreeNodes) And the same tree gives the following in-order traversal: B,H,I,D,A,C,F,E,K,G,J. Can you draw the tree structure?
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Mar 28, 2014
Exercise the Coin class using a driver class in which 5 coins are flipped, as a group, 1024 times. Display the number of times exactly 4 tails are obtained. Display the number of times exactly 5 tails are obtained. Use an array of Coin.
how to put an object into an array?I know how to make a coin class with a Heads and Tails, but I dont know how to make 5 coins all at once.
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Apr 10, 2014
I know the first line below creates an object but the second line creates an array of cars, I'm just not sure how it does that. I can see sportsCar is one object in the array but the others are written in a different way. It seems there should a couple names there instead. Please explain the syntax in this code that's highlighted. I don't know how to make sense of it and I've read through the book where I got it where it explained creating objects.
Auto sportsCar = new Auto("Ferrari", 0, 0.0);
Auto [] cars = {new auto("BMW", 100, 15.0), sportsCar, new Auto()};
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Apr 24, 2014
I have a list of objects in my bean (ex: List<Apple> applies = new ArrayList<Apple>() ).The object has several fields (ex: supplier, color, width, height, breadth, etc.)I want to show this list on the front end. However I also want to allow the user to edit the attributes of the apples.So from the front end I will have like a list of fields where a set of fields is related to a single object in the list.I would also like to add/delete apples.
What first came to my mind is to map every field in the object Apple to a List. For example if Apple has field suppliers and field color then in the bean I would create two Lists, List<String> supplier, and List<String> color.From the front end I would display the contents of these Lists rather then the List<Apple> apples.T
he name of the field would be the same for each set of attributes.On save (form submit) the Lists would be re-populated with the field values (changed or not) and then I would be my Apple objects from the bean before saving in database.However I am not sure if there is something in JSF that can achieve this in a simple way, working only with List<Apple> rather than adding additional Lists.
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Jun 29, 2014
okay,I created a program that demonstrated an array holding a number of objects, each from different classes.the printout I got for the first program ended up being gibberish. when I made the program a second time, I got the correct result.I've been trying to pinpoint the anomaly but I can't seem to find it. So ill try breaking down what I did?
Goal:The purpose of the program was to have a single Class (we'll call the Class 'Animal') to pass the parameters of a previously made method. This method would, amongst other things, call on an array.Further, I would then make subclasses of the Class Animal, and then use them as well to pass the method parameters, thus demonstrating subclasses can be used in place of the super class.
3 of these classes were made purely to as a "place setter". the Classes called "Cat" and "Dog" respectively were created to be subclasses of the Class Animal (with no other code inside them aside from "extends Animal)the 3rd "place setter" called "ClasstoHoldObjects" was created to be the array class (ClasstoHoldObjects itself has no code in it aside from the class name)these are the ones we want.Animal class (which holds the coding meant to be used).Here is the Animal Class
public class Animal {
private ClasstoHoldObjects[] thelist = new ClasstoHoldObjects[5];
int i = 0;
public void add(ClasstoHoldObjects x){
if(i < thelist.length){
[code]....
the print out was this next, im putting THIS line in the array... june_6.Dog@a0dcd9 (and the same by the Cat object).I recognize june6 as the package name.
finally, I erased extra lines as well as comments and simplified class names to make the code more readable. If you want the original, or some class names are a bit off- I could give you the original with all its comments and longer named classes
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Sep 18, 2014
I have a program I want to make (text based, no gui). There is the main class, an Employee class (sort of a template), a CrewMember class, and a Manager class.
I'll put the code for each class an explain the problem I have.
package polymorphism;
import java.util.Random;
public class Start {
public static void main(String[] args) {
Random rand = new Random();
Employee staff[] = new Employee[5];
for(int i = 0; i < staff.length; i++){
[Code] ....
Some of the code is a bit incomplete simply because I ran into the problem. As you can see I made an array in the Start class and it holds objects of Employee type, but create a new instance of either a crew member or a manager, sets their wages, hours, and bonus if applicable. I know if I create an array of a certain type, I can't call upon the subclass' method (Manager in this case) because it has a new method that I added. What I'm trying to do is pretty much call upon the getSalary() method in the Manager class/object, but of course I can't. What way would i be able to do that? I tried looking for some answers. I read about making the superclass abstract and implementing it into the subclasses. Would that be an option?
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Mar 29, 2014
I'm new to Java and have not been able to figure this out. I'm reading a text file that contains this:
110001 commercial 500000.00 101
110223 residential 100000.00 101
110020 commercial 1000000.00 107
110333 land 30000.00 105
110442 farm 200000.00 106
110421 land 40000.00 107
112352 residential 250000.00 110
The output goes to a text file and should look like this:
COMMERICAL
FARM
LAND
RESIDENTIAL
101 600000.00
105 30000.00
106 200000.00
107 1040000.00
110 250000.00
I'm creating the output file, but it only contains the categories and not the details below them. Cant seem to figure out why.
Java Code:
package propertylistings;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
[Code] ....
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Feb 14, 2015
An array has objects with String firstName, String lastName, int ID, char examType('M' or 'F'), and int score. Every object has both Midterm('M') and Final('F'). The array has to be sorted by the first Midterm- 'M' and immediately followed by the Final ('F') of the same person (object). Im having troubles with coming up with a proper algorithm with gettin the Final- 'F' after Midterm for the same person.
Java Code: public static Exam[] collateExams(Exam[] exams) {
Exam [] r = new Exam[10];
r = exams;
int[] position = new int[10];
int index = 0;
for(int i = 0; i < exams.length; i++)
[Code]...
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Oct 27, 2014
I have an assignment where I need to add an interface to an already-created program. I have an array of objects, where each object has a name, price, and priority.
In my original program (which worked), I had all of the objects in 1 class. The professor said that I should split up the name/price/priority into 3 different classes. So what I have is an array that belongs to an interface, and name/price/priority implements. But I am having trouble loading the data into the array (from another class) once I am done with loading name.
Here is what I have so far.
public class Main {
public static void main (String[] args){
Interface[] arr = new Interface[7];
Scanner keyboard = new Scanner(System.in);
System.out.println
[code]....
Line 18 in the ItemName class is giving me an error, and I know it is because arr is of type Interface, and I am trying to assign is a String. But I don't know how to do this. In my original program I was able to do arr[x].getName(); but when I do that in Main, I get errors.
how to assign to an interface array from multiple classes.
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Jul 23, 2014
'm working on a program that is to act as an inventory for a book store. There are two classes (Store and Book), and numerous methods which you will see in my code. The program is supposed to read in an inventory from a file which contains 10 books (each row in the file represents a book with an ISBN number, the price of the book, and the number in stock)and store this file into an array of type Book[]. There is then to be another method to process a purchase interactively. The Store class is also to keep a count of how many books were sold at the time of closing and also how much was made that day.
I'm having some difficulty figuring out how I should set up the purchase processing method though. I've written out how I think it would be set up (not too familiar with the terminology, but I think it would be called pseudo code?) I'll include that now along with a few other notes.
public Book[] purchase(String isbn, double price, int copies) {
int itemsSold;
double totalMade;
Scanner input = new Scanner(System.in);
System.out.println("Please enter the ISBN number of the book you would like to purchase: ");
[Code] ....
So basically here's what needs to be accomplished with this portion of code:
1.Ask the user to enter the ISBN number of the book they'd like to purchase.
2.Search the array for the object that contains that ISBN.
3.If the ISBN isn't found in the array, display a message stating that we don't have that book.
4.If the ISBN is found but the number of copies is 0, display a message saying the book is out of stock.
5.If the ISBN is found and the number of copies is greater than 0, ask the user how many copies they'd like to purchase.
6.If the number they enter is greater than the number of copies of that book in the array, display a message stating that and ask them to enter another quantity.
7.Once the purchase is complete I need to update the array by subtracting the number of copies of that particular book that was purchased.
8.Print the updated array.
9.Display a count of how many books were purchased, and how much money was made from the purchase.
I know that code has a lot of holes in it, but I'm just trying to get everything together and figure out how to do each step.
The part I'm stuck on right now is trying to figure out how to search the array to first see if the ISBN that was entered is in the array, and then to find the number of copies of the book with that ISBN number.
In case it will visualize what this array looks like, here's a print out of the array from a sample run I just did.
ISBN: 1234567, Price: 31.670000, Copies: 0
ISBN: 1234444, Price: 98.500000, Copies: 4
ISBN: 1235555, Price: 27.890000, Copies: 2
ISBN: 1235566, Price: 102.390000, Copies: 6
[Code] ....
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Aug 15, 2014
if, instead of an ArrayList, can I do the following to initialize a Dyanmic array ? :
First, in my class, I have :
class Example{
private int rows;
private int columns;
private AnotherClass[][] 2DArray;
public Example(int rows, int columns){
this.rows = rows;
this.columns = columns;
[code]....
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Apr 23, 2014
I want to keep count of how many students are in my array. the array i made up of objects from other classes. like the class Student how do i do this. i have tried contains but better way it to to a loop to go through the array and determine if each object is a particular type but i don't know how to do this. here is the code
import java.util.*;
import java.util.ArrayList;
public class Driver {
public static void main(String[] args){
/* Comments required
PersonFileReader pfr = new PersonFileReader("person.dat");
ArrayList<Person> testData = pfr.readData();
Database db = new Database(testData);
[Code] .....
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Mar 16, 2014
I want to create a simple app that takes a name from the console then compares the name to a small phone book,when the name matches another name it will return the associated phone number.
I have a small contacts class which has name and number fields,Then I have a phone book class which populates an array with 4 contact objects that I can compare the entered number against.
here is my contacts class
public class Contact
{
String name;
int number;
[Code].....
In the main method I am just trying to print out one of the fields for one contact to see if I can actually access it to compare it to the name entered.Its saying "MaryJones" cannot be resolved to a type.I'm guessing I cant create all that code in the constructor?
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Feb 8, 2015
I am trying to build a method that takes an array of object and adds a new object of that type to the end of it . ONLY ALLOWED TO USE ARRAY , NO ARRAYLISTS VECTORS ECT . i realize that if the array is full you can use the java copy array method to make a new array and double its size until a certain point . The MAX AMOUNT OF OBJECTS is a constant that is 100 but for some reason even when executing my code i keep getting null pointer exceptions or index out of bounds errors , i have written this method many times now with out any success.
My question is how do I write a method that adds an object to the end of an array and if there are no spots left copies the current array into a new array and extend the size
private Animal [] objects;
final int MAX_ANIMALS = 100;
public AnimalObject()
{
objects = new AnimalObject[MAX_ANIMALS];
}
public AnimalObject(Animal[]a)
[Code] ....
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