How To Add Order Entries
Jan 17, 2014
im new to java and i wanna make a program using java that can add order entries for a restaurant but how to... i was hoping something that would ask to person to input one or two items and before it calculates the total amount to be paid it will ask the guy who inputs the amount whether or not there are additional orders or not before it prints out the total amount... I am pretty sure it will need an if-else statement..
import javax.swing.*;
import java.util.Scanner;
public class OrderCalc {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame aFrame = new JFrame("OrderCalc");
aFrame.setSize(500,250);
aFrame.setVisible(true);
[code]....
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Mar 1, 2014
One of the random number generators in Java extract the higher-order bits of the random number in order to get a longer period.
I'm not sure if I understand how this is done. Suppose that the random number r = 0000 1100 1000 1101. If we extract the 16 most significant bits from r; is the new number r = 0000 1100 or r = 0000 1100 0000 0000?
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Jan 26, 2014
Any link to the accurate explanation of binary trees in java?
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Nov 15, 2014
I have a web form with a field Department. I want to add Sub Departments(unknown number) of one Department and then further Sub Sub Departments(unknown number) of one Sub Department. How I will make a form and how I will add this data in attached database. I have one solution:
One Department field with a button to add any sub department if any. By clicking on button, a new row will be generated with another text field and new button. In this way, it will go on. Tree like structure.
But I have another solution, JSF Tree to add or delete entries on the run time. But the problem is that I am unable to find any example of JSF tree like structure populated from database and in which we can add or delete entries on run time and on the same time these entries may also be stored in database.
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Aug 6, 2014
I have a database of peoples names linked up to a from to enter a new employee.The form has a previous and next button that should cycle through the employees alphabetically.What im doing the cycle by now is ID which isnt in alphabetical order and just goes by the order they where entered in.
Is there any way to cycle through alphabetically instead? Is running a query each time the next/previous button is pressed the correct way or should it just grab all the names in the array. Theres probably 150 names.
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Jul 8, 2014
I have an editable JTable that has a lot of JComboBox's as cell entries. I would like to be able to "arrow over" to said cell, and with a pressing of either a numerical button or by typing the first letter of the String selection (possibly followed by a second), be able to select the appropriate selection from the cell's JComboBox. I have tried to add a key listener to the JComboBox itself, which works given that I click on said cell and show its menu.
How would I go about ensuring that, when focus is on the cell itself, and I start typing, the appropriate selection is chosen?? (I think this might get into key binding, but I don't know if I have to try it from the scope of JTable, or from that JTable's TableModel (which I have made my custom version of).
Here is what I have so far (everything but SandwichNumber, SandwichName, and Oregano uses JComboBox): [URL] ...., how would I do such key binding?
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Apr 13, 2014
I think I'm about 90% complete with this program but I'm stuck on my adding entries method. It gives me a runtime error which says:
Enter the name:
Bill
Exception in thread "main" java.lang.NullPointerException
at Phonebook.addEntry(Phonebook.java:70)
at Phonebook.main(Phonebook.java:49)
Here is my code:
/*
* This program asks the user for input for a name, phone number and notes up
* to 200 entries. It stores every contact in a file. Type 'h' for help while
* running this program.
*/
import java.util.Scanner;
import java.io.*;
[code]....
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Mar 9, 2014
Assignment: Develop a GUI-based program to read the entries of a matrix from a text file. The first number is the number of rows; the second number is the number of columns. The remaining numbers are integers between 1 and 9 in row by row order. Scan the matrix, highlight (display the entries in different color) all cells that form a group of five cells with the same value horizontally, vertically or diagonally.
Example of text(.txt) file:
7 7
3623161
3666669
3936293
3594955
3289867
2493998
1399998
Example of output:
3623161
3666669
3936293
3594955
3289867
2493998
1399998
* ^^this would be what it would look like when displayed in the GUI. But it would be colored. Anything that has 5 in a row ...My Class File:
// GUI-related imports
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Scanner;
// File-related imports
[code]....
EX.
0=black(when there is no combo. of 5)1=blue(horizantal combo of 5)2=red(vertical combo of 5)3=green(right diagnol combo of 5)4=purple(left diagol combo of 5)
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Jun 22, 2014
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]....
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Dec 7, 2014
I have a 2d array that i am manipulating. In my class i have a constructor that takes the dimensions of the array and within th econstructor i need to randomly fill the array. However, when i try to manipulate it in the test program, all that prints out are the default values.
here is the class
import java.util.*;
import java.lang.Math;
import java.util.Arrays;
import java.util.Random;
class SummerStats
[Code] .....
And here is the printout
Enter number of rows(people):
3
Enter number of columns(years):
3
Enter number of person to find sum salary:
1
Enter year to find Max salary of that year:
1
[]
[]
The max salary is at index: (0, 0, )
The largest salary ocurred in year: 0
The sum of person 1 is: 0.0
The total of all salaries is: $0.0
The max salary in year 1 is: 0.0
The average salaries for each year:
0.0, 0.0, 0.0,
The total salary for each person is recorded below.
And the last method called doesn't finish or printout ie the program doesnt end
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Aug 15, 2014
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]....
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Feb 18, 2015
I am using the following code to create a dialog , but my need is user can select only 1 entry . Using this code
can select multiple items by pressing Ctrl ... How it can avoid ... My current code is
Java Code:
SecureCloudStorage_Service service = new SecureCloudStorage_Service();
List<String> files = service.getSecureCloudStoragePort().listFiles();
SelectFileDialog dialog = new SelectFileDialog(this.getFrame(),true,files);
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
int x = (screenSize.width - dialog.getWidth()) / 2;
int y = (screenSize.height - dialog.getHeight()) / 2;
dialog.setLocation(x, y);
dialog.setVisible(true); mh_sh_highlight_all('java');
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Feb 19, 2014
Write an interface Directory to manipulate entries in a telephone directory for the University. The interface must support the following operations:
1) The ability to insert new entries into the directory. Entries should be stored in alphabetical order of surname.
2) Delete entries from the directory either by name or number
3) Provide a lookup method that will find the extension no of a member of staff given his/her name. You should try to make this method run as efficiently as possible.
4) Change a person's telephone number
5) Print the telephone directory in a neatly tabulated fashion.
Write a class ArrayDirectory that implements this interface using an array to store the telephone directory information. The class must store the surname and initial for each member of staff and their telephone extension (a four digit number which may start with a zero). You may find it useful to define a class Entry to store information about individual entries. The entries should be read into the array from a text file consisting of multiple lines in the following format:
Surname<tab>Initials<tab>Telephone extension
Write a main program that reads in data from a file and then tests all the methods of your class interface. Note it is not necessary to write data back to disk (even if it has changed) in this project.
For data insertion and lookup, you should measure the performance for the average case (e.g. looking up a record in the middle of the data). To do this you can use the static method System.currentTimeMillis() which returns the time in milliseconds. To get an accurate measure of the time to perform an operation it is a good idea to perform each operation 1000 (or even 10000) times and measure the time taken. This will remove any problems due to the system clock having a coarse granularity (not ticking very often). Make sure you only time the method and not any input/output associated with it. Your documentation should include a discussion of these results.
Part 2
You decide that your solution to part 1 may be too slow to be useful when used with a real large telephone directory and make the following changes to attempt to improve the performance of your program:
1). Provide a second implementation (ListDirectory) of the Directory interface using the Java Collections List interface and LinkedList classes.
2). The changes in 1) should make adding, deleting and modifying records more efficientbut will probably reduce the time to lookup numbers. To overcome this you use a technique called hashing. Instead of storing all the records on one list you use a series of lists. The data for all people whose surname begins with "A" is stored on the first list, records for all people whose surname begins with "B" on a second list and so on. Write a third implementation (HashDirectory) of the Directory interface using this technique.
Again, you should measure the performance for the best, worst and average cases of implementations 1) and 2) above. Compare the efficiency of each of the 3 implementations in your documentation.
Part 3
Choose one of your 3 implementations from Parts 1 and 2 and embed it in a graphical user interface that allows users to perform all the methods in the Directory interface using a mouse and keyboard appropriately.
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Mar 12, 2014
this is the following task i am trying to do. Write an interface Directory to manipulate entries in a telephone directory for the University. The interface must support the following operations:
1) The ability to insert new entries into the directory. Entries should be stored in alphabetical order of surname.
2) Delete entries from the directory either by name or number
3) Provide a lookup method that will find the extension no of a member of staff given
his/her name. You should try to make this method run as efficiently as possible.
4) Change a person's telephone number
5) Print the telephone directory in a neatly tabulated fashion.
Write a class ArrayDirectory that implements this interface using an array to store the telephone directory information. The class must store the surname and initial for each member of staff and their telephone extension (a four digit number which may start with a zero). You may find it useful to define a class Entry to store information about individual entries. The entries should be read into the array from a text file consisting of multiple lines in the following format:
Surname<tab>Initials<tab>Telephone extension
The part that i am stuck on is trying to do the entry method, delete entries method, loop up method, change persons telephone number and be able to print it.
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Feb 14, 2015
I have an ArrayList of employee and ArrayLsit of bosses, and I want to keep those people in a temporary ArrayList , then ordain alphabetically by name, to sort I use the interface comparator.
The problem comes when I will order 2 ArrayList(workers and bosses), because every time I call I use these functions or not is ordered (sortByNameAlphabetical())
public class Employee {
private String name;
public String getName() {
return name;
}
@Override
public String toString() {
return name ;
[Code]...
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Sep 17, 2014
I came across this code which proves that variable initialisation occurs before even constructors are called.However, I am confused over some things.
Firstly, from my understanding, when a new House object is created in this line House h = new House(); , the no-arg constructor of the House class is called.
Since the no-arg constructor House() is called, why are all the creation of Window objects being run first ? Shouldn't Java jump straight into the no-arg constructor House() ?
class Window {
Window(int marker) { System.out.println("Window(" + marker + ")"); }
}
class House {
Window w1 = new Window(1); // Before constructor
House() {
// Show that we’re in the constructor:
System.out.println("House()");
w3 = new Window(33); // Reinitialize w3
[code]...
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Sep 22, 2014
I'm learning the swing options of Java, and my first exercise was the typical Chat Room. I got everything right: TextField, TextArea, the jpanel at left side and the buttons inside of it. BUT I can't order the 2 buttons (1 north, 1 south). I've already looked for answers, but didn't find anything and I tried to asked the teacher, but she was too lazy to look for the error. Here is my code:
f=new JFrame("Chat Room");
b1=new JButton("Send");
b2=new JButton("Emoticons");
public void showWindow(){
p1=new JPanel();
f.getContentPane().add(p1,BorderLayout.EAST);
p1.add(b1,BorderLayout.NORTH);
p1.add(b2,BorderLayout.SOUTH);
}
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Nov 20, 2014
I am unsure of something. In the following class, which is read first; the static field or the main method?
class Test{
static int a = 3;
public static void main(String args []) {
//some code}
}
I put some code in Eclipse and have tried to look at the hierarchy. It would point to all static fields being initialized in order from top to bottom, including the main method.I had thought that the main method was always the first thing in a public class to be initialized, regardless of where in the code it resides. Am I reading the Eclipse hierarchy wrong? I find Eclipse very difficult, especially since I typically code in Textmate. I just want to see how my code is operated upon,
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Dec 3, 2014
This is how the for loop works for the row,right?
for(int i=array.length-1;i>=0;i--)
{
}
I want to know how the for loop works for the column?
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Dec 29, 2014
I have some codes as below:
public class Hello
{
public static void main(String[] args) {
new Student().fun();
}
}
class Person
[Code] ....
Now the output is "Person". if i hide the "PRIVATE" in class PERSON, that is, method PRINT in class STUDENT override the same method in its father class, then the output is "Student". Why? I mean, how does the program know what PRINT method should be called?
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Oct 9, 2014
This is what I have to do:Write a program that takes a string of someone's name and prints it out last name first. Your program must use pointers, not array subscripts. You may use the available string manipulation functions if you find an opportunity.
Example:
"George Washington"
"Washington, George"
I am not sure how to reverse the name, I have been looking in my textbook and online and cannot figure it out. This is what I have put together so far, it does not run. At the end it says unnecessary return value.
import java.util.*;
import java.util.Scanner;
public class Test {
public static void main ( String [] args ) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter name: ");
String name = sc.nextLine();
String lastname = "";
String firstname = "";
for(int i = 0; i < name.length(); i++) {
if(name.charAt(i) == ' ')
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Feb 3, 2015
I am trying to sort an array that I have by alphabetical order but I am having problems. Firstly the code that I have used to sort the array may not even do what I need but havn't got far enough to test it yet so go easy on me . I have read in some places when searching how to do this that I would have to create my own bubble sort in order to achieve this but I was hoping that Java had a built in sort method/function. Secondly I lack the knowledge in java to be able to assign an existing array or even a variable to the newly sorted array as I need the unsorted version with the original name and the newly sorted version as another.
code (This is not all of the code, I decided to include only what I thought was relevant):
import java.util.Arrays;
public class Sentence {
private String words[];
public Sentence(String[] words) { this.words = words; }
@Override
public String toString() {
return "Sentence{" +
"words=" + Arrays.toString(words) +
[Code] ....
Is it possible to shorten the sort function to just this?
public String sorted() {
return Arrays.sort(words);
}
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Nov 29, 2012
I want to write an application that inputs a sentence, tokenizes the words with method split and reverse the words (not the letters)...I am stuck at the last part: how to reverse them...should I use the method reverse(); ?
Here is my code..
import java.util.Scanner;
import java.util.StringTokenizer;
public class ReversedWords {
//execute application
public static void main( String [] args) {
//get sentence
[code]....
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Dec 22, 2014
I am trying to make a program that reads a word and display if the letters are in ascending order or not in ascending order(All kind of letters, capitals ). I have made a code but its not 100% correct. My code:
class Main
{
public static void main(String args[]) {
System.out.print( "#Enter text : " );
String text = BIO.getString();
[code]...
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Apr 27, 2014
I need to put my scores in ascending order how do i do that?
public static void main(String[] args) {
char[][] answers = {
{'A', 'B', 'A', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
{'D', 'B', 'A', 'B', 'C', 'A', 'E', 'E', 'A', 'D'},
{'E', 'D', 'D', 'A', 'C', 'B', 'E', 'E', 'A', 'D'},
{'C', 'B', 'A', 'E', 'D', 'C', 'E', 'E', 'A', 'D'},
[Code] ....
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Apr 6, 2015
How do I take the union between an object called on and the object passed in the parameter?I have an interface:
Java Code:
import java.util.Set;
/**
* An extended Set where additional functionality is added
*/
public interface NewSet<T> extends Set<T> {
[code]...
Now, the union method requires a NewSet object to be called on. The Union will be performed between the object called on and the object passed in the parameter, which is set.How do I call on a NewSet object in order to take the union between the object called on and the object passed in?Do I just do:
Java Code:
public NewSet<T> union(NewSet<T> set) {
NewSet<T> calledOn = new ArrayList<T>();
// ...
} mh_sh_highlight_all('java');
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