I am trying to add Point objects into an Array.This is my code to read in data
Java Code:
public void readRoadMap(File road) {
try{
String line;
BufferedReader br = new BufferedReader(new FileReader(road));
while((line = br.readLine()) !=null){
this.points.add(new Point(line));
[code]....
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] ....
This is what he wants: He wants us to prompt the user to input x values and y values (that will be entered into an array when clicking one of the two buttons (this one will say: Add point)). When they click the second button (draw lines), it should take all the points and draw a line that connects all the points together using a method that we write. In the method we have to call the paint method up which the lines will be drawn. The lines drawn should be touching every point added. It shouldn't have parameters. It will also use Graphics painter = getGraphics(); We can't use frames either.
I have everything up until the method understood.
How to write a method that will draw a line from points inputted that is called up in the action listener when the second button (draw lines) is pressed.
In one part of my small code, I want to make a sky which will have area of 200 * 200 pixels, and inside I want to have 100 randomly placed stars (I tried to make an array of 100 elements - of class "Point").Each star should have its x and y coordinate, and I don't know how to do it. I tried many things.
import java.util.Random;
import java.awt.Point;
public class Sky {
private Point[] stars = new Point[100];
public Sky() {
for(int i = 0; i< stars.length; i++){
Random r = new Random();
int u = r.nextInt(199);
int v = r.nextInt(199);
//x[0].setLocation(u,v);
21stars[0].x = 5;
[code]...
I need to write a program but I am having hard time filling an array of triangles...we are suppose to have 3 different classes..1 class of points..1 class of triangles and 1 main method which apply all those..here what I have been come up so far for the point class which I believe is good..
public class Point {
private float x;
private float y;
//Making x equal to the x coordinate and y equal to the y coordinate like on a graph
public Point(float xCoordinate, float yCoordinate) {
x = xCoordinate;
y = yCoordinate;
[Code] ....
Now here is my question how I am suppose in the main method fill an array of triangles for 100 triangles or less?
Operator is undefined for argument type. Error is located at the end of the binary search method array[position] < key
import java.util.Arrays;
public class binarySearch {
public static <T extends Comparable<T>> int binarysearch(T key, T[] array) {
int start = 0;
int end = array.length - 1;
int position =-1;
while (start <= end && position == -1) {
[Code]....
What would be a good and simple algorithm to find the shortest route between two points in a 2D array[grid] ? There can be certain obstacles in the grid i.e. some of the cells may be inaccessible. I tried googling for it and found that A* is the best for this but I am just a beginner and would like to start with something much simpler.
View Replies View RelatedI've two classes: Student and ArrayListExamples (which has my main method in it).
The student class acts pretty simply at the moment with a constructor that takes a name, surname and ID number. I've tested it and it seems to be working. My issue is with adding an object to an array list, here is my effort:
public class ArrayListExamples {
private static int MAX_SIZE = 50;
static Scanner sc = new Scanner(System.in);
public static void main(String[] args) {
ArrayList<Student> students = new ArrayList();
[code]....
I know the last loop to add the student objects is wrong.I'm calling the student ArrayList add method with a student object whose constructor requires two strings and an integer. Why isn't this allowed?
Having trouble adding Class (Dollar) objects to a HashSet (money), i have done this before with arraylists and i understand that HashSets are different in that they cannot contain duplicates. Currently when this code is compiled i am getting "null" printed when I run the "howFullDatWallet" method.
import java.util.*;
public class Wallet {
private HashSet<Dollar> money;
private int walletSize = 0;
private int walletFiller = 0;
/**
* Constructor for objects of class Pocket
*/
public Pocket(int walletCap)
[code]....
I have to read in a file that that has Student, Employee, Faculty....such as name, last name, salary...etc
Example of a file input
Java Code: Student, John, Doe, [email]johnDoe[At]yahoo.com[/email], 123,Wonderland Ave, 21323,TX
PhoneNumber,Cell,111,222,3333
Student, Jesus,Satan,[email]jesus[At]satan.com[/email,666, HeavenHell Dr., 666666,CA
PhoneNumber,Work,111,333,5555 mh_sh_highlight_all('java'); Java Code: while(input.hasNext()){
[code]...
There is more code, but it's repetitive. Now, I keep getting an error. Array of bounds. I believe i get the error because the phone number. The phone number is on the next line..I created a different arraylist for phonenumber, but I dont know how to match it with the correct person, student, employee...etc.
I decided to write a small Java program to experiment around with BorderLayout, because I'm developing a Java game and I need to have 2 objects placed in a single JFrame at the same time, and everyone I asked said I need BorderLayout to do that.Before you answer: Also, is using BorderLayout the best option for adding multiple video game oriented objects such a sprites to a JFrame?
So the Java program I wrote is supposed to place a JButton on the JFrame and ALSO place a graphic component (a rectangle in this case). The problem is, only the button shows up, as can be seen in the image link below: URL....
Here is the code:
**main.java** --> The main method class + JFrame/JPanel/JButton constructor
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class main {
[code]....
I am working on a text based adventure game. (This is NOT OOP at all) The problem comes in at my second if statement inside my loop, it is not adding 1 to my array locations[] it keep printing location[0] then a 1 at the end. Not really sure what is going on here. I would like it to when I type "Go north" it adds 1 to locations[]
E.G
locations[0]
Go north
locations[1]
go north
locations[2]
package com.PenguinGaming;
import java.util.Scanner;
public class Game{
[code]....
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.
I have a main class:
Java Code:
public class Main {
public static void main(String[] args) {
Player[] playerList = new Player[] {new Player("Daniel", 3, 3, 2, 1, 1, 3),new Player ("Player2", 2, 4, 1, 6, 3, 2)};
System.out.println(Player.getPlayer());
}
} mh_sh_highlight_all('java');
[code]....
and whenever I run it, it prints out the last player, so I was wondering how to identify them separately, but still use the array, as (I believe) it is the most efficient way.
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()};
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.
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
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?
I am working on a assignment that has to do with array lists, it mainly has to do with adding new elements, telling then where it is it located, if the memory block is empty , ect. so far i have been having problems with my indexOf method which should display the array cell number that a input element E is in, and if it is not in there it should display a -1.
public class MyArrayList<E>
{
private E[] data_store = (E[])new Object[2];
private int sizeofa = 0;
private void resize()// makes the array list bigger if need {
E[] bigspacemaker = (E[])new Object[data_store.length * 2];
for(int x = 0 ; x< sizeofa ; x++)
[Code] ....
Error message:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 512
at MyArrayList.indexOf(MyArrayList.java:28)
at MyArrayListDemo1.main(MyArrayListDemo1.java:26)
I have been trying to space out output on a Java console window so that I have three columns with 6 rows of data from three different arrays. The code I have so far outputs the data with no problem however the spacing between the columns is uneven. My loop so far is made up as follows
for (int i = 0; i < printVotes.length; i++) {
System.out.println(printNames[i] + "
" + printVotes[i] + "
" + printPrecent[i] + "%");
}
As you can see I have been manually adding the space between each element of the array but this means that the space between each element is different because the size of each element is different if work out a loop that works out an even amount of space between the elements and then print this along with the elements ....
So I'm trying to write a method which returns the number of vowel characters in arraylist. My idea is to convert the arraylist element by element to array each time iterating through the array counting the vowels of that element. When I started I immediately got an error(surprise, surprise). Excuse me if the problem is too simple, but I am very new to programming.
At line 9 I get the following error "Type mismatch: cannot convert from String to int". I want to get the element at this position, not to convert to int..
ublic class One {
public static void main(String[] args) {
ArrayList<String> bla = new ArrayList<String>();
bla.add("aaa");
bla.add("brr");
bla.add("unn");
}
public static ArrayList<String> averageVowels (ArrayList<String> list){
String[] arrListWord = list.toArray(new String[list.get(0)]);
return list;
}
}
Im making a simple code to add an array to a List (the code im referring to is <String> )
import java.util.*;
public class L5_ArrayListProgram {
public static void main(String[] args){
String[] things = {"lasers","ghouls", "food", "dark"};
List<String>list1 = new ArrayList<String>();
for(String x: things)
list1.add(x);
My simple question is - what are the <String> ...<String> for? I understand it makes the list1 variable a string, but why is it made like this? do we usualy use <String> when we need to make a variable a String?
I'm having trouble conceptualizing something. I will post the code, it's works exactly as it should. I create an array and Hash Map to display periodic table of elements information after allowing the user to search by element name or symbol. I want the user to also be able to add elements to the periodic table. I can't really conceptualize how I am going to do that with an array I've already created.
Here's code:
//Create element objects.
//Here is where I create my "elements" array, and where I could like to prompt the user to add elements, if desicred.
Element[] elements = {new Element("Hydrogen", 1, "H", 1.008,1,1), new Element("Lithium",3, "Li", 6.94,2,1)}; //
//Maybe it seems if I prompt the user here to add new element names, symbols, weights, etc, I would be overwriting
[Code] .....
Working on my final which is due today, its' and Inventory Program which I have been working on for the last 5 weeks. My Buttons on my GUI Add/Delete doesn't add items to my inventory. I'm not sure exactly what wrong with my code, I'm not getting any error and the Program compiles just fine, I just can get the Items to add of delete.
my Delete button starts on line 281
my Add Button begins on line 319
//
/** Purpose:the purpose of this software is to display inputs as wells as the stocks and price of inputs,
*as well as display a 5 % restocking fee per dvd and for the entire Invenotry of each object.
*adding a GUI to the code. Adding a Previous button to the existing code allowing the user to cycle through
*the Inventory list freely. Also adding a graphics logo to page. adding more buttons and allowing program to
*save new items added to the inventory.
**/
//Needed Imports for GUI
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import javax.swing.border.EmptyBorder;
import java.io.File;
import java.io.IOException;
[Code] .....
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]);
Creating an Arraylist and adding item to that array, refer below code
ArrayList<String> sjarr = new ArrayList<String>();
Statement1:
String arritem1 = new String("First array item");
sjarr.add(arritem1);
Statement2:
String num = "text will decide";
sjarr.add(num);
Both adds the String item to array list but puzzling what makes the difference....