My current lesson in Java is about ArrayLists and I'm having a tough time to understand this bit of code: This exercise is concerned with the problem of deleting a block of items from an ArrayList.
public static void deleteBlock( ArrayList<String> strings, int n )
{
for ( int i = 0; i < n; i++ )
{
if ( strings.size() > 0 )
strings.remove( i );
[Code] ....
This is the output: [rosion, sion, on, n]
I've a ArrayList with dogs on, and I've a function that should allow me to delete a dog from the register and if the dog was found it prints "The dog was deleted" and if the dog doesn't exist in the arraylist it should print "the dog couldn't be found".
Everything works perfect until I shall delete a dog that is not first on the list. Then the program shows first "dog was not found" and on the row after "the dog was deleted" if the dog was second on the list. If it was third I will get 2 messages that the dog wasn't found and then that the dog was deleted. I've no clue why it prints both else and if!
public static void taBortHund(){
//Har tar vi bort hund fran listan
//System.out.println(hundlista);
System.out.print("Vilken hund vill du ta bort? ");
String hunden = tangentbord.nextLine();
for (int taBort = 0; taBort<hundlista.size(); taBort++){
[code]....
It isn't messing up it just keeps making me make my arraylist static and i'm not sure why.
public class driver
{
private static ArrayList<AddItems> items;
public driver()
[Code]....
I try to create a jsf project within ejb which is add new car with entering attributes listing attributes and search by make.
Add and list methods working well , but have problem of list method. I tryed many combinations (using enhanced loop, iterative loop) but i cant provide working well. Always outputText returns nothing ,when i enter attributes.
Here is ejb code for adding ,getting and listing car items :
@Stateful
public class CarsBusiness implements CarsBusinessLocal {
List<Car> cars;
public CarsBusiness() {
cars = new ArrayList<Car>();
[Code] .....
I am working on the Kevin Bacon - 6 degrees of bacon problem. I want to take my Array List and use the index and Values that I have saved in it as the Key and Value of a Hashmap. Below is my code.
HashMap<Integer, ArrayList<String>> actors =
new HashMap<Integer, ArrayList<String>>();
ArrayList array = new ArrayList();
try (BufferedReader br = new BufferedReader(
new FileReader("actors.txt"));)
[code]...
saving each one in it's own spot. I want to use the index of each one as the key to find it in the Hashmap....
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
set("", "");
method, it only sets the last one that is called.
Example:
set("section1", "section1Item");
set("section2", "section2Item");
set("section3", "section3Item");
Only section3 would get set, and not the others.
Otherwise, if the file contained a section already, then each section (section1, section2, section3) would get set.
Here's how I set the data to the file:
public static void set(String section, String data) {
files.openFileWriter();
files.file.delete();
reCreateFile();
String beforeItem = section + ":" + files.dataList.get(section);
if(files.hasReadData) {
[Code] ....
And here is how a retrieve the data and set them to my arraylist/hashmap:
public void getData() {
String line = null;
openFileReader();
StringBuffer sb = new StringBuffer();
[Code] ....
Having trouble figuring out the code in order to find the price column for all items in a ArrayList. So far i have:
private double calculateSubtotal() {
try {
myConnection = DriverManager.getConnection(DATABASE_URL);
myStatement = myConnection.createStatement();
myResultSet = myStatement.executeQuery("SELECT price FROM menu");
[Code] ....
I am not sure if i am going about this the right way or not?
Basically I am trying to make a POS system and need a way to print a receipt whether there are 1 items sold or 50. So I used a Arraylist. This is the format for the printer that is needed:
printer.printNormal(POSPrinterConst.PTR_S_RECEIPT, " 2 200 Tx Hashi Chop Sticks" + LF);
This is what I tried to do:
ArrayList<String> receiptLine = new ArrayList<>();
public void captureSales(){
receiptLine.add("Test");
System.out.println("Size of the receipt list is: "+receiptLine.size());
System.out.println("Element at index 1: " + receiptLine.get(0));
printer.printNormal(POSPrinterConst.PTR_S_RECEIPT, " " + receiptLine.get(0) + LF);
Error:
Size of the receipt list is: 1
Element at index 1: Test
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
set("", "");
method, it only sets the last one that is called.
Example:
set("section1", "section1Item");
set("section2", "section2Item");
set("section3", "section3Item");
Only section3 would get set, and not the others.
Otherwise, if the file contained a section already, then each section (section1, section2, section3) would get set.
Here's how I set the data to the file:
public static void set(String section, String data) {
files.openFileWriter();
files.file.delete();
reCreateFile();
String beforeItem = section + ":" + files.dataList.get(section);
[code]....
And here is how a retrieve the data and set them to my arraylist/hashmap:
public void getData() {
String line = null;
openFileReader();
StringBuffer sb = new StringBuffer();
[code]....
I am having an issue deleting a node for a tree for one of the cases.The cases for deleting a node are:
1. if its the root set it to null
2. if its a leaf, have its parent point to null
3. if the node you want to delete does not have a right child, have deleted nodes parent point to delted nodes only child
4. find the nodes predecessor(next largest value), have have predecessor's left child be deletes left, and preds right to be deletes right. then have deletes parent point to pred and finally, delete preds old spot (the one that is giving me an issue, I believe)
The pre order of the tree I am currently on is 50 5 4 10 190 100 100 200 190 201
or------------------50
-------------5--------------190
---------4------10-----100-------200
--------------------100---190--201
I am trying to delete 190 (which should be the first one)but when I try to print out the list after I delete, I get a stack overflow error when I try printing everything out.I am pretty sure that it has something to do with me hooking up the nodes incorrectly since error occurs for case 4, since it prints out just fine when I deleted previous nodes (like a leaf).Here is my delete method: (note, ignore my determineX and checkOtherHalf methods)
public boolean delete (E item) {
if(root == null){
return false;
else if(item == root){
root = null;
return true;
[code]....
I have confirmed that it is a pointer issue: I need to assign replacements old parents left child to null, to stop it, but idk how.Here is a screen shot of it when I debug it
How to delete word "kumar" from sentence
import java.util.*;
class kumar
{
public static void main(String args[]) {
Scanner in=new Scanner(System.in);
System.out.println("Enter a sentence");
String s=in.nextLine();
s=s=" ";
[Code] ....
I do not get any output nor any error....
ok so for class I'm supposed to Write a class DeleteElements that prints out an array and asks the user which number should be deleted and then deletes that number, if it exists from the array.
The first part tells me to
Step 1
o Start by simply searching the element.
o Pseudocode:
-Create an array and populate it with random positive integers.
-Print the array to show the user which elements the array contains.
-Use a WHILE loop to search the element—a WHILE loop is better than a FOR loop because you can stop when the element is found by using a Boolean value in the loop condition—and also keep track of the location where the
element might be found.
-If the element is not found, output the error message, “Number not found.”
-Otherwise output the message, “Number found at index #.” where # is the index where the element is.
-Print out the array.
Example of output:
34 65 12 76 45 39 86 71 67
Number to delete: 76
Number found at index 3
This is what I've got so far but I can't seem to get the "number not found part to print out only once".
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;
public class DeleteElement {
public static final int ARR_LENGTH = 10;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
Random ran = new Random();
[Code] ....
Current output result if value does not exist:
61 89 52 16 20 71 37 91 4 36
Number to delete:
23
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Current output result if value exists:
97 48 51 22 89 5 42 97 43 96
Number to delete:
89
Number found at index 4
Maybe I'm not understanding the part about the boolean value.
I am want to delete the first line of text file using RandomAccessFile class. My Input file "bulkwfids.txt" has the data as below:
234567
345578
455678
566667
Expected output needs to be(first line deleted):
345578
455678
566667
But the actual ouput I am getting is as follows:
78
56
345578
455678
566667
Here is the code snippet I have written:
import java.io.*;
class DeleteLine {
public static void main(String [] args) throws FileNotFoundException, IOException {
RandomAccessFile raf = new RandomAccessFile("C://Users/hp/Desktop/bulkwfids.txt", "rw");
raf.readLine();
[Code] .....
out.println("</select>");
out.println("<link rel='stylesheet' type='text/css' href='css/table.css'/>");
out.println("<input type='text' id='searchText'/>");
out.println("<input type='hidden' id='hide' value='" + selected + "'/>");
out.println("<input type='button' value='Search' onclick='getData()'/>");
[Code] .....
What I want is ..on selecting heading check box...all the below check box should get selected....and clicking on delete button which i will create later on...i want multiple rows to be deleted from database....
Refer image ....
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] .....
My method below works fine to print a matrix but when it prints every row, it is printing extra 4 white spaces which is not required. How can I delete those extra spaces at the end? when I use
System.out.print((matrix[i][j] + " ").replaceAll("^s+", ""));
It trims every thing including the spaces I needed for my matrix. So where should I put replaceAll("^s+", "") ?
Java Code:
private static void printMatrix(int[][] matrix) {
System.out.println();
System.out.println("Matrix:");
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix[i].length; j++) {
System.out.print(matrix[i][j] + " ");
}
System.out.println();
}
} mh_sh_highlight_all('java');
My method below works fine to print a matrix but when it prints every row, it is printing extra 4 white spaces which is not required. How can I delete those extra spaces at the end? when I use
System.out.print((matrix[i][j] + " ").replaceAll("^s+", ""));
It trims every thing including the spaces I needed for my matrix. So where should I put replaceAll("^s+", "") ?
private static void printMatrix(int[][] matrix) {
System.out.println();
System.out.println("Matrix:");
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix[i].length; j++) {
System.out.print(matrix[i][j] + " ");
}
System.out.println();
}
}
I have a program for a phone directory. It needs to add, delete, append, and edit telephone records. I've gotten it to write and search the files. Just need to get it to delete and edit them.
Here's what I have so far:
import java.nio.file.*;
import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
import static java.nio.file.StandardOpenOption.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
[code]....
I want to delete the shape i have drawn on the panel. Here is my code
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.geom.Rectangle2D;
[Code] ....
Why it is not deleting my rectangle.
If my file name is MyBigXMLFile.xml it won't delete but if I rename it to mybigxmlfile.xml it will delete. How do you get around the case sensitive issue?
View Replies View RelatedI am following those three tutorials and I have completed it with success.
( [URL] .... )
( [URL] .... )
( [URL] .... )
But then, as author haven't implemented removeCountries method I tried to create it. What I did initially was to just add to class Countries this method:
public boolean removeCountry(Country country) {
return countries.remove(country);
}
But although compiler wasn't complaining it didn't work. Actually it worked last night (before reboot) but not today. Must be some SOAP iterator/binding thing or whatever. Or I thought that it worked but in fact it didn't.
Here are original classes:
//-------------------------------
public class Country {
String CountryId;
String CountryName;
public Country() {
super();
[Code] ....
I would like to avoid my own iterator as JDeveloper can generate automatically iterators for webservices, but if I can't get it that way, what would be better way to write above mentioned iterator in removeCountry method?
Is there any way to remove object directly with something like this:
co.countries.remove(o);
co.removeCountry(country)
using method
// This left unused
public boolean removeCountry(Country country) {
return countries.remove(country);
}
from class Countries?
Parameters should be set by web service iterator.
I have a problem with this application , I have a button that allows users to delete entry's from the array list, but i've noticed when i go back and click display entry's the correct entry has not been deleted.....for example if i enter a,1,2 then b,1,2, then c,1,2 in fields, then delete c,1,2 when i actually go to display the data entered a,1,2 will be gone not the one i entered.
So it seems to be deleting the entry at index 0 of the array list no matter what and not the chosen item..Delete Button Code
private void deleteBtnActionPerformed(java.awt.event.ActionEvent evt)
{
if (numTf.getText().equals("") || nameTf.getText().equals("") || yearTf.getText().equals(""))
{
JOptionPane.showMessageDialog(null, "All fields must be full");
}
else if (count == 0)
[code]....
I'm working on a GUI Phonebook and need getting a button to work for deleting a contact. I identified the error I get in the Gui class where it says applyDeleteEntry(); on line 106 with comments. The entries are stored in a .txt file which is created for you.
Main class:
import javax.swing.*;
import java.awt.*;
public class Main{
public static void main(String args[]) throws Exception{
Phonebook mainPhonebook = new Phonebook();
Gui mainGui = new Gui();
[Code] .....
I have used FileInputStream class but its not working properly to divide the bits into blocks.I will attach the coding
public static void main(String[] args) {
ReadFileExample newclass = new ReadFileExample();
System.out.println("cryptography");
[Code].....
In the following piece of code Iam confused as to where the InputMismatchException in the catch block is thrown on the first place? Is the InputMismatchException thrown automatically with declaring to throw the exception?
import java.util.*;
public class InputMismatchExceptionDemo {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
boolean continueInput = true;
[code]....
Is it a best practice to return from try block or place return statement after try-catch when we intend to return a value from a method(* Catch block is being also used to rethrow the exception)??
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