I don't really get the concept of how I "insert" an item into an array. I get a cannot find symbol error when I try to. I think its because I'm losing focus. What sort of code would "insert" an item into an array? I just want a goal of conceptually how I would do it.
Anyways, here are the instructions for the exercise:
Write a new class method, insert, for the Item class that takes three arguments - an Item[] array, an Item newItem, and an int k - and inserts newItem into array at index k, discarding the last item of the array (that is, the item originally at index array.length - 1).
Here is the uneditable code:
public class Item {
private int myN;
public Item( int n ) {
myN = n;
}
public String toString()
[Code] ....
I get a cannot find symbol error, but I thought I was doing as I was supposed to. I thought you had to have an ArrayList to be able to insert or delete an item from an array. How can you take a primitive object, like an array, and insert something into it. My idea of it was a[i] would be replaced with a[i + 1]. I know I'm getting this concept wrong because that's what I tried to do.
How can I insert a new item at the middle of a BookList . I have also got a Book class represting Book objects and a inner class BookNode referencing them.
public void add(Book newBook) { BookNode newNode = new BookNode(newBook); if (firstNode == null){ // no nodes in the list so add newNode at start firstNode = newNode; tempNode = newNode ; }
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. **/
I am trying to have a user select from a printed out array list, instead of having the user type in the "bill type" each time there is a bill to avoid user error as much as possible. For example I would like to have it print out like this:
"Select bill type from list:
1. Rent 2. Car 3. etc..."
and I would like the user to choose a number and not type in the "bill type". I don't want to use "Switch case" because it would need to be an expanding and I don't think "switch case" can do that.
Here is the code:
package homebudget; class Spending { //Do i need a totalAmount variable? String type; double amount; int year, month, day; public Spending()
[Code] ....
case 2: //Give option to enter a new expense or pick from list. //How to do this? If Statement that doesn't list duplicates, or a while search?
resp = JOptionPane.showInputDialog("Enter the type of expense:"); type = resp; resp = JOptionPane.showInputDialog("Enter the amount of the expense:"); amount = Double.parseDouble(resp);
I have read through some of the posts on insert sort /arrays and see close but not exactly what I'm looking for. I don't want to use a library to do work for me, I want to do it myself and understand it.
OrderedArrayList.java // import static org.junit.Assert.assertEquals; public class OrderedArrayList<T extends Comparable<T>> { // T is a variable that contains a class type, array of T things private T[] arrayA; // changed to private per example private T[] arrayB; int numElements = 0;// number of elements full (not null), used in multiple methods. numElement -1 = back
Question 1: I am working on an assignment where I have to remove an item from a String array (see code below). When I try to remove an item after entering it I get the following error "java.lang.NullPointerException." I am not sure how to correct this error.
Question 2: In addition, I am having trouble figuring out how to count the number of occurrences of each string in the array and print the counts. I've been looking at other posts but they are more advanced and I have not yet learned how to use some of the tools they are referring to.
private void removeFlower(String flowerPack[]) { // TODO: Remove a flower that is specified by the user Scanner input=new Scanner(System.in); System.out.println(); System.out.println("Please enter the name of the flower you would like to remove:
I need to choose the value of a list item in jsp. There are many employees in various departments and i need to choose that employees in department wise.
Example. I have two list items in jsp
1. Select dept_no,dept_name from departments 2. SElect emp_name from employees, departments where emp_dept_no=curr_dept_no and curr_dept_no = dept_no
These two are the list items. When i choose the department from the first list item i need to display the employees in that particular department in the second list.
I'm trying to make a calendar that, when you click on the date, the result are stored in a map and visualized in a table that refers to a container.
I successfully created the map mechanism, but I have a problem on the list....
I add the rows in this way:
Object newItemId = container.addItem(); Item riga = container.getItem(newItemId); riga.getItemProperty("Timestamp").setValue(fara); riga.getItemProperty("Date").setValue(asa); . How can I delete a row in the list, when all I have in input is the "Timestamp" information, in a Long value?
Can a JCalendar be used as an item. I cannot find and appropriate combodatepicker or at least one that looks like a standard combobox. I cannot get an answer from google search all i can get is how to add normal items.
So I drew a menu in DrawingPanel extends JPanel, that gets user input of number of players...etc. I also have a boolean, when true, the board is drawn, but apparently, right when I run, the boolean is checked, returns false and so board isn't drawn at all. When the user finishes input, the boolean becomes true, but the board doesn't get drawn. So my question is, how do I draw something not immediately when the program is ran?
I was wanting to select an item in a comboBox and display it in a text field but all it's doing at the minute is retrieving the first item in the comboBox and placing that in the txt field
String value = (String) comboBoxEnv.getSelectedItem().toString(); if(comboBoxEnv.getSelectedItem()!= null){ txtTo.setText(value);
I have an array list in my GUI class of an aplication , the app reads in 3 fields from the user and saves these to an array list allowing the user to enter more fields to be added to the arraylist, when displaying back out to the user the same entry displays multiple times, for example if i entered , a,b,1 then c,d,2 and then e,f,3 into the app when i press my display button it would just throw back e,f,3 three times rater than the three different entries...
Constructor and instance variables
private String name; private String number; private int year; private int count; private ArrayList<StudentData> myList; private StudentData myData;
So I got an interesting challenge today. I think logically I know what I have to do but I'm at a complete loss as for the actual coding implementation. So I have to develop this method called moveToBack(T entry). What this is meant to do is as implies, move entry to the back of my queue. As simple as it sounds, I know that I cant just move its position that simple. I know that I'll have to essentially remove whatever the desired value is, and then re-add it to the back of the queue. The interesting problem with this, however; is that I know that the FIFO property exists for queue's.
So if the desired entry to be moved is at the 3rd position of 4, I'd have to remove positions 1 and 2 to finally get to 3. But I want it to keep those values still. So I assume what I'll have to do is remove each element of the queue (it'll only be 5 entries max for the purpose of the project) and save it somewhere, then empty the queue and finally add the elements back in while waiting and putting the desired element to the last position.
If that's the case, I'm really curious on how I would do this. I have 4 files, 2 interfaces, the main class that contains the methods and what not for the queue, and a 4th class that'll be used for running test data and testing the methods of the program. Now, I wont add the interfaces code below because those are fine and all methods that need to be added are. I just gotta improve my moveToBack method so that it does what its supposed to. (I know I should have exceptions instead of my very poor else statements, but for this project it's not necessary.)
public abstract class NoDuplicatesQueueWilson<T> implements NoDuplicatesQueueInterfaceWilson<T> { private int MAX_QUEUE = 5; // Default array size, small for testing purposes private T[] items; // The array of the queue. private int front; // The first entered item of a queue. private int back; // The last entered item of a queue. private int count; // A counter.
When I try popping everything off my stack, it leaves the last item alone. The size comes out correct when I print it out, so that cant be the issue, I think. Also, it doesnt even print it out if I do
for(int i = 0; i <= s1.Size() + 1; i++)
it still leaves one value left. What am I doing wrong?
public class Test { public static void main(String[] args) { Stack<String> s1 = new Stack<String>();
s1.Push("first"); s1.Push("2nd"); s1.Push("3rd"); s1.Push("4th"); System.out.println(s1); try { System.out.println("The top item is: " + s1.Peek());
I need instantiating 3 instances of the RetailItem
//Instantiate 3 RetailItems RetailItem jacket = new RetailItem(); ITS TELLING ME: constructor RetailItem in class RetailItem cannot be applied to given types jacket= jacket.setDescription("Jacket"); <------- ITS TEllING ME: cannot find symbol jacket = jacket.setUnitsOnHand(12); jacket = jacket.setPrice(59.95);
I have a selection listener attached to a TreeView as shown below
treeView.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<TreeItem<Pair<VideoSourceType, String>>>() { @Override public void changed(ObservableValue<? extends TreeItem<Pair<VideoSourceType, String>>> observable, final TreeItem<Pair<VideoSourceType, String>> oldValue, final TreeItem<Pair<VideoSourceType, String>> newValue) { // do something treeView.getSelectionModel().clearSelection(); } };
What I want to do is to "do something" and then clear the selection so that it can be selected again. However, I cannot re-select the same item from the TreeView until I first select a different item.
We have this piece of code and we must make a search for a key. if the key exist it returns true if not false. Plus we must insert a key in the class. If it is already in there we say hey its already in and we don t put it again...
package askisi2; import java.util.*; public class mtree { protected class tnode { public int k1; public int k2; public int k3;
i found some problem for this jsp code. Actually I'm new in jsp. I'm trying to insert some data in a sql table in jsp by user input. Here's my code but i couldn't completed it.
