Smoothing Input Using Ring / Circular Buffer?
Aug 11, 2014
Normally I would just implement a circular buffer and be happy but there's a fundamental problem with that.OK, so I'm working on a piece of cheap Android hardware that's being used for demo purposes. One of the problems, primarily because it's cheap (imo) is that the screen input is not clean and is interfering with the UI experience. Specifically when gliding your finger, the result is quite non linear.
I know that's not the best drawing but it sort of explains the problem to a degree. In reality, it's probably a bit smoother than that, but there is still noisy data getting in, and the problem is it causes the UI to be jittery at times.
I would like to smooth this using something like a Circular Buffer. Now I figured the best way to do this would be to store the last 4 float inputs and then effectively calculate the next value based on an average, so say our input was this:10, 15, 20, 25 and 35 is the current input.
15 - 10 = 5
20 - 15 = 5
25 - 20 = 5
Then for the next value, 35 - 25 = 10. 10 + (3 * 5) = 25 / 4 = 6.25...Then adding 6.25 to the previous value resulting in this: 10 15 20 25 31.25 which would appear theoretically smoother. However I'm struggling to work out in my head the best way to implement such a function.
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Nov 7, 2014
So it is the question: This program implements a simple "decoder ring". It will prompt the user for a message to decode and decode the message based on the following substitution rules:
ABCDEFGHIJKLMNOPQRSTUVWXYZ will map to
ZEBRASCDFGHIJKLMNOPQTUVWXY
abcdefghijklmnopqrstuvwxyz will also map to
ZEBRASCDFGHIJKLMNOPQTUVWXY
any other characters (like space, punctuation, will map to themselves)
so if it sees an 'A' (or an 'a'), it will map to 'Z', etc... All i could think of is this but can't figure out the rest.
import java.util.Scanner;
public class DecoderRing
{
public static void main(String[] args)
{
String1[] = 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z';
String2[] = 'Z','E','B','R','A','S','C','D','F','G','H','I','J','K','L','M','N','O','P','Q','T','U','V','W','X','Y';
}
}
Not sure, what things are necessary such as switch statements or if and else or for loops and such...
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Aug 20, 2014
I want to develop an application, which shows a circular window with close, maximize buttons.
I want to create something like this: [URL]
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Mar 5, 2014
a buffer reader , how does it work and what is the code for it ?
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Sep 4, 2014
Due to compatibility reasons, I need to be able to store a random C buffer inside of a Java String. THis means that the Java String should contain the exact same buffer information (i.e. byte sequence) as the original C buffer. How would I do that?
All the functions I found will always somehow code/decode the C buffer, and modify its content depending on the selected encoding.
I need to do this inside JNI. Following is what I have:
Java Code:
unsigned char* cBuffer=getCBuffer();
// Transfer the C buffer to s:
jstring s=NULL;
if (env->EnsureLocalCapacity(2) >= 0)
{
jbyteArray bytes = env->NewByteArray(signalLength);
if (bytes != NULL)
[Code] ....
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Feb 12, 2015
For the program I have to create, I need to be able to work with the elements of a circular doubly linked list to do the following:
Find an element in the list (specified as an argument)
Insert an element after a specified element (specified as an argument)
Delete an element (specified as an argument)
Display the elements in the list
I can insert elements and display the elements, but I can't figure out how to search for an element, insert an element after a specified element, or delete an element.
What I am having trouble with is passing the elements in the list as arguments for searching, deleting, inserting after an element.
public class doublyLinkedList {
private Node pointer;
private Node dLL;
private int count;
[Code] .....
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Apr 6, 2014
I am creating a josephus java program with a circular linked list.This is what the methods are suppose to do
a. size(): Returns the number of items in the list.
b. isEmpty(): Returns true if the list is empty and false otherwise
c. advance(): Moves the cursor from the current position to the next item. If the cursor is at the end (tail) of this list, calling advance() should make the cursor refer to the first element in the list. If the list is empty, this operation should have no effect.
d. getCurrent(): Return the String value in the node referenced by the cursor unless the CircularLL is empty in which case write an error message to System.err.
e. add(String data): Adds a new item to the list by creating a newNode and linking it to the end of the circular linked list. The last node should point to the new node and then you should make lastNodeInserted point to new node as well.) Please note that a circular linked list is always circular. The last node should point to the beginning node. When there is only one node in a CircularLL, its next should point to itself. This method updates currNode when the first node is added, and always updates lastNodeInserted and numNodes. Take care when adding the first node this is a special case and should be handled differently.
f. remove(): If the list is empty, write an error message to System.err indicating that an attempt was made to remove from an empty queue and return null. Assuming the list is't empty, this method removes the node currently referenced by the cursor, reassigns the cursor to point to the next node in the list, and returns the String value stored in that node. To keep the list linked, you'll need to locate the previous node to the one youre removing and connect its next to the node which follows the one youre removing. Create a local Node variable (prev) to find it. Consider and handle the special case when there is only one node and youre removing it. And make sure to update lastNodeInserted whenever you remove the node that it is pointing to.
g. toString(): This should return a String representation of the circular linked list, with the first value displayed being the data of the first node added (not the data in the last node).
public class CircularLL {
private class Node {
String data;
Node next;
public Node(String data) {
this.data = data;
this.next = null;
[code].....
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Mar 26, 2014
i am having a below piece of code in my worker thread. In my output i am getting xml records from the database. I'm sending this output to a input stream & finally to a sax parser.My query is, before sending to the parser i need to store the input stream in buffer. The buffer should store 1000 records. For every 1000 records the parser should be called from buffer.
while (orset.next()) {
output = orset.getString("xmlrecord");
writeCount++;
InputStream in = new ByteArrayInputStream(output.getBytes("UTF-8"));
InputStream inputStream = new ByteArrayInputStream(output.getBytes("UTF-8"));
Reader reader = new InputStreamReader(inputStream,"UTF-8");
[code]....
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Feb 17, 2014
I have the following code which always gives me java heap space error because of line number 65 due to string buffer append method in this line, I don't know why?
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
import samy.*;
import java.util.Scanner;
public class InfixToPostfix {
OrderedList list = new OrderedList();
Scanner input = new Scanner(System.in);
public StringBuffer postfix = new StringBuffer();
[Code] .....
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Jul 12, 2014
I'm writing a simple application, that provides a Swing GUI to a bounded-buffer problem. The application is composed by:
- Main.java: it creates a map of four threads (four instances of the class MyThread). Also it creates a shared database (an instance of the class Database) between the four threads.
- MyThread.java: it's an extension of Thread, and it shows a Swing GUI associated to this thread. Each thread is associated a GUI.
- GUI.java
- Database.java: it's an extension of ArrayList and and it can contain a maximum of five elements. An element is an instance of the class User. Also it implements put() and extract() method consistent with the algorithm of bounded-buffer problem.
- DatabaseException.java: it's a simple message.
- User.java
public class Main {
public static void main(String[] args) {
Database db = new Database();
Map<String, Thread> tdg_m = new HashMap();
for (int i = 1; i <= 4; i++) {
tdg_m.put("T" + i, new MyThread(db));
[Code] .....
The issue is the following. When the database is full, and i try to put an element, the GUI freezes. The same problem occurs when I try to extract an element from the empty database.
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Apr 3, 2014
what is the difference between stringbuffer and string builder?
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Oct 14, 2014
My homework is a Double Circular Link list and when i write implements Iterator it gives me a an error when I compile it the same for my subset method...
ERRORS :DoublyCircularList.java:55: error: DoublyCircularList.iterator is not abstract and does not override abstract method remove() in Iterator public class iterator implements Iterator<T>
^
Note: DoublyCircularList.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error
import java.util.Iterator;
public class DoublyCircularList<T extends Comparable<T>> extends LinkedList<T>implements Iterable<T>
{
Node<T> first;
int size;
public DoublyCircularList(){
first = null;
size = 0;
[code]....
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Apr 15, 2014
So I have this file in which has a few sentences on a single line. What I need to be able to do is read the file and then take each word and create a token out of it. Then what it does is it selects the first letter of every 5th word, uppercase it, and then allow me to use append it via a stringbuffer object to create a word out of it.
I know I'll need to use a string tokenizer but I'm not sure how to do so in a way that makes each word separate and how to tell it to only hit the 1st letter of every 5th word.
Here's what I've come up with so far, but I'm currently at a loss at what to do and my textbook/documentation is just not working.
Java Code:
String line; // The line we read from the file.
char letter; // The first letter of each 5th word.
String sw; // The completed string.
public static void main (String [] args)throws IOException {
[Code] ....
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Jan 31, 2015
I'm trying to create a circular array which prints out 8 numbers that increase by one and don't exceed 9. If they do, the remaining numbers are printed from 0 on-wards. I have code below which does this job, but it doesn't really use an array to loop back.
Java Code:
package Practice;
public class Practice
{
public static void main(String[] test)
{
number(7);
number(9);
[code]...
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Oct 27, 2014
So I'm trying to build a queue, first in first out, (so add to the head remove from the end) using a linked list for use in another program, I'm having a problem dequeueing where the program seems to run indefinitely without giving an answer, so my suspicion is its caught in a while loop but how and why I can't figure out.
public class CircularQueuelist {
private Node head = null;
private int size = 0;
private class Node
{
int data;
Node next;
[Code] ....
My logic seems sound, I basically look for when the second node over from the current one I'm on is a reference to the head, and then skip the one in front of it using setting currents. next link to current.next = head, severing the link to the last node.
This is what my driver looks like, I enqueue items 1-10 and then use the iterator to make sure it worked out fine and check size, its when I dequeue that I run into a problem, the program runs indefinitely.
public class Queuetest {
public static void main(String[]args)
{
CircularQueuelist test = new CircularQueuelist();
for (int count = 0; count < 10; count ++)
[Code] ....
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Nov 12, 2014
I am trying to write a program that will generate a QR Code from an input text and also display some information about the input/output bits. So far I have created the frame and what to do next. And I'm not sure if I am on the right track since my level of programming is not that great. By the way, I am using zxing libraries from GitHub. I know, there are plenty of generators online for the QR Code, but that is not what I am looking for. As you can see on the attached image, I am more interested in the efficiency of encoding 2D data. Also, I noticed that almost all the online projects regarding 2D codes are for Android. Which is not very useful.
// QR Code Generator
package qrcode;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
[Code]....
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Jul 14, 2014
So I was going to try to create a program that prompts input and creates a file (That didn't exist before) with that input as name.Then, the program prompts inputs after stating questions such as 1 + 1, then if the user inputs an answer, put "Question # = Correct "or" Wrong.Code SO Far:
Java Code:
import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
public class File_Read {
public File_Read() {//File_Read is the Interactive object
[code]....
So that it puts the Correct or Wrong into the file.
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Apr 9, 2015
Where do I input this segment?
Scanner user_input = new Scanner( System.in );// This line goes at the top with the other global variables
public void getUserInput(){
System.out.print("Enter litres: ");
litres = user_input.nextDouble( );
System.out.print("Enter mileage: ");
mileage = user_input.nextDouble( );
System.out.print("Enter speed: ");
speed = user_input.nextDouble( );
[Code] ....
This is my client file.
class Client{
public static void main(String []args){
Bike R1=new Bike(5.0, 60.0,30.0);//create bike object with params
Bike R2=new Bike();//without params
System.out.println(R1.increaseSpeed());//calling methods
System.out.println(R1.maxDistance());
System.out.println(R2.increaseSpeed());
System.out.println(R2.maxDistance());
}
}
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Mar 4, 2014
Why do i not get a value 0 when my input is 0.
import java.util.Scanner;
public class Dec2Hex {
public static void main(String[] args){
int dec;
String hexStr = "";
int radix = 16;
[Code] .....
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Nov 13, 2014
I have been coding in my class at school (Grade 11 Computer science) and i just downloaded the program on my computer at home, unfortunately i cannot access my computer notes at home and i also dont remember certian specifics of coding, so my question is how would i get user input to create a program. The comments are the parts i dont remember. (I am trying to slowly build my memory with this stuff)
Here is my code so far:
import java.util;
[highlight=java]
public class hello_world {
public static void main(String[] args) {
string name;
//WHAT DO I PUT HERE????
[code]....
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Oct 14, 2014
I have it so it gives me the sum of any digit, i just cant figure out how to get only the odd digits to add up. for example if I were to type 123. The odd numbers = 4 but using this program i get 6
class SumOfDigits {
public static void main(String args[]) {
int sum = 0;
System.out.println("Enter multi digit number:");
[Code] ....
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Apr 24, 2014
Im trying to get the user to input the rows one by one but my input stops after the first. the examples i looked at in my book had this way i used as well. i are my rows and j are my columns. What is the correct way to do it?
import java.util.Scanner;
public class Exercise08_01 {
public static void main(String[] args) {
[Code]....
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Apr 19, 2014
I'm working on creating a dice game and getting the users input is giving me a really hard time. I have the main game working but this part I'm stuck on. The problem is that it's not giving me the chance to enter the second input when I ask for the game.
//Create Scanner object
Scanner keys = new Scanner(System.in);
//Get chips
[Code]....
*****This is what I get when I run it
run:
How much money would you like to change? 50
You now have $50 in chips.
What game do you want to play? You did not pick dice.
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Jul 24, 2014
I'm trying to get the input of several JComboBoxes and execute a statement depending on which option the user chose for example if destination combo Box = japan duration combo box = 10 days and hotel combox = hotel then print line "welcome" I have tried many options but not getting the desired outcome. at the moment I'm using an if statement with only 2 of 3 of the J combo boxes but it's not working here's my code:
String[] Dest = new String[] {"Select Destination","Crete", "Paris", "Croatia"};
String[] Accomodation = new String[] {"Select your Accomodation","Hotel", "Villa", "Bed in Breakfast","Youth Hostel"};
JComboBox<String> comboDest1 = new JComboBox<String>(Dest);
JComboBox<String> comboAccom1 = new JComboBox<String>(Accomodation);
[code]....
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Jul 24, 2014
So I'm currently self learning java. Currently I'm trying to write my own code with an else-if ladder to spit out the data on different types of ships. For some reason, when I put in the input, it always puts in my final else statement instead of the other ones. I've ran this code manually inputting a char (in the code the variable is ch) to see if the else-if ladder runs properly, and it does. But for some reason the input isn't running the ladder right.
class Ships {
public static void main (String arg[])
throws java.io.IOException {
char ch;
int length, beam, draft, min, max;
[Code].....
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Oct 24, 2014
I need to write an input validation while using the do-while statement. I feel like most of it is good except that it gets stuck inside the brackets of the do statement. After I enter an input, it just keeps asking me over and over for an input. Then I have to make it s if you enter an input that is out of range, you have to keep entering an input until it is in range.
Java Code:
do
{
System.out.print("Please enter the amount of spaces the letters will shift... ");
shift = uInput.nextInt();
} mh_sh_highlight_all('java'); Java Code: public class ShiftEncoderDecoderDriver
{
public static void main(String[] args)
[code]....
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