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• How to write C++ audio processing applications?

  - by cesko82

  Hi everyone, I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to manage it, such as FFT, circular convolution ecc ecc. I want to learn C++ programming basically for one reason: it's very important in the professional world!!! And I think it's one of the most used to write applications working with audio, especially when it's about real time processing. Ok, after this small introduction I would like to know first, which are the most used libraries to work with audio processing in c++?? I was longer looking on the web but i couldn't find a lo of working stuff. (I work under linux with eclipse CDT enviroment). Then I would like to know if there are good sources to learn how to write some working code, such as for example how to write a simple low pass filter. Basically now i will not write real time applications, I would like to start from the processing of a WAV file, or even better an MP3 file, so basically on vectors of samples. Let's say that basically for now I would like to extract the waveform from an audio file, and save it to a thumbnail or to a PNG image. Ok, for now I think it's all I would need. Any ideas, advices, libraries, books, interesting sources about that? Thanks a lot in advance for any kind of answer. Giovanni.

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• Counter that will remember it's value

  - by owca

  I have a task to operate on complex number. Each number consists of double r = real part, double i = imaginary part and String name. Name must be set within constructor, so I've created int counter, then I'm sending it's value to setNextName function and get name letter back. Unfortunately incrementing this 'counter' value works only within costructor and then it is once again set to 0. How to deal with that?Some constant value? And second problem is that I also need to provide setNextNames(char c) function that will change the counter current value. The code : public class Imaginary { private double re; private double im; private String real; private String imaginary; private String name; private int counter=0; public Imaginary(double r, double u){ re = r; im = u; name = this.setNextName(counter); counter++; } public static String setNextName(int c){ String nameTab[] = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N", "O","P","Q","R","S","T","U","W","V","X","Y","Z"}; String setName = nameTab[c]; System.out.println("c: "+c); return setName; } public static String setNextName(char c){ // //don't know how to deal with this part // }

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• Why does std::cout convert volatile pointers to bool?

  - by Joseph Garvin

  If you try to cout a volatile pointer, even a volatile char pointer where you would normally expect cout to print the string, you will instead simply get '1' (assuming the pointer is not null I think). I assume output stream operator<< is template specialized for volatile pointers, but my question is, why? What use case motivates this behavior? Example code: #include <iostream> #include <cstring> int main() { char x[500]; std::strcpy(x, "Hello world"); int y; int *z = &y; std::cout << x << std::endl; std::cout << (char volatile*)x << std::endl; std::cout << z << std::endl; std::cout << (int volatile*)z << std::endl; return 0; } Output: Hello world 1 0x8046b6c 1

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• Perl, share package variable without Export

  - by Mike

  I'm creating a group of Perl scripts, and I would like to have one package store a group of constants. I don't want to export them using Exporter because there will be quite a few and I don't want to pollute the namespace. Since there will be so many, I don't want to require the user to be forced to manually specify which they will be using. I think the best way to just use the packagename::var syntax, however it doesn't seem to be working as I expect it to. I illustrate this problem in the below code This is settings.pm, the module that will hold the global settings #!/usr/bin/perl #settings.pm use strict; use warnings; package settings; our $foo="hello world"; 1; Below is the main script #!/usr/bin/perl #script.pl use strict; use warnings; use settings; print settings::$foo; It gives this error message instead or printing hello world Bad name after settings:: at ./script.pl line 8.

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• Basic Tomcat Servlet error.

  - by ajay

  package mypackage; import java.io.*; import javax.servlet.http.*; import javax.servlet.*; public class Hello extends HttpServlet { public void doGet (HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { PrintWriter out = res.getWriter(); out.println("Hello, world!"); out.close(); } } web.xml file is as follows: <?xml version="1.0" encoding="ISO-8859-1"?> <web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4"> <display-name>Hello, World Application</display-name> <description> This is a simple web application with a source code organization based on the recommendations of the Application Developer's Guide. </description> <servlet> <servlet-name>HelloServlet</servlet-name> <servlet-class>mypackage.Hello</servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloServlet</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping> </web-app> I am then doing ant all , ant reload and also /etc/init.d/tomcat restart But I get this error on browser: HTTP Status 404 - /hello/ type Status report message /hello/ description The requested resource (/hello/) is not available. Apache Tomcat/6.0.26 What could be wrong?

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• How can I test this SQL Server performance Utility?

  - by Martin Smith

  As part of my MSc I need to do a three month project later this year. I have decided to do something which will likely be useful for me in the workplace and spend the time getting to understand SQL Server internals. The deliverable for this project will be a performance advisor looking at a variety of different rules. Some static such as finding redundant indexes, some more dynamic such as using XEvents to find outlying invocations of stored procedure execution times when certain parameters are passed. I am struggling to come up with a good way of testing this though. I can obviously design a "bad" database and a synthetic workload that my tool will pick up issues on but I also need to demonstrate that it has real world utility. Looking at the self tuning database literature it is common to use TPC benchmarks but I've had a look at the TPCC site and it looks very time consuming to implement and not that good a fit to my project's testing needs in any event (I would still be able to "rig" it by the decisions I made on indexing or physical architecture). Plan A would be to find willing beta tester(s) but in the event that isn't possible I will need a fallback plan. The best idea I have come up with so far is to use the various MS sample applications as examples of real world applications. e.g. http://msftdpprodsamples.codeplex.com/ http://www.asp.net/community/projects/ Does anyone have any better suggestions?

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• Java JSTL / EL: nesting

  - by NoozNooz42

  I really don't know how to name this question, it's great if anyone with 2K+ rep can edit this title to better reflect my question (the fact that I can't name this easily is probably why I can't Google the solution). I've got this, which is working: <c:choose> <c:when test="${sometest}"> Hello, world! </c:when> <c:otherwise> <fmt:message key="${page.title}" /> </c:otherwise> </c:choose> And I want to change it to this: <c:choose> <c:when test="${sometest}"> <c:set var="somevar" scope="page" value="Hello, world!"/> </c:when> <c:otherwise> <c:set var="somevar" scope="page" value="<fmt:message key="${page.title}">" </c:otherwise> </c:choose But of course the following line ain't correct: <c:set var="somevar" scope="page" value="<fmt:message key="${page.title}">" How can I assign to the somevar variable the string resulting from a call?

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• How to arrange business logic in a Kohana 3 project

  - by Pekka

  I'm looking for advice, tutorials and links at how to set up a mid-sized web application with Kohana 3. I have implemented MVC patterns in the past but never worked against a "formalized" MVC framework so I'm still getting my head around the terminology - toying around with basic examples, building views and templates, and so on. I'm progressing fairly well but I want to set up a real-world web project (one of my own that I've been planning for quite some time now) as a learning object. I learn best by example, but example-based documentation is a bit sparse for Kohana 3 right now - they say so themselves on the site. While I'm not worried about learning the framework as I go along, I want to make sure the code base is healthily structured from the start - i.e. controllers are split nicely, named well and according to standards, and most importantly the business logic is separated into appropriately sized models. My application could, in its core, be described as a business directory with a range of search and listing functions, and a login area for each entry owner. The actual administrative database backend is already taken care of. Supposing I have all the API worked out and in place already - list all businesses, edit business, list businesses by street name, create offer logged in as business, and so on, and I'm just looking for how to fit the functionality into a MVC pattern and into a Kohana application structure that can be easily extended. Do you know real-life examples of "database-heavy" applications like directories, online communities... with a log-in area built on Kohana 3, preferably Open Source so I could take a peek how they do it? Are there conventions or best practices on how to structure an extendable login area for end users in a Kohana project that is not only able to handle a business directory page, but further products on separate pages as well? Do you know any good resources on building complex applications with Kohana? Have you built something similar and could give me recommendations on a project structure?

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• Php sting handling triks

  - by Dam

  Hi my question Need to get the 10 word before and 10 words after for the given text . i mean need to start the 10 words before the keyword and end with 10 word after the key word. Given text : "Twenty-three" The main trick the having some html tags tags need to keep that tag with this content only the words from 10before - 10after content is bellow : <div id="hpFeatureBoxInt"><h2><span class="dy">Top News Story</span></h2><h3><a href="/go/homepage/i/int/news/world/1/-/news/1/hi/world/europe/8592190.stm">Suicide bombings hit Moscow Metro</a></h3><p>Past suicide bombings in Moscow have been blamed on Islamist rebels At least 35 people have been killed after two female suicide bombers blew themselves up on Moscow Metro trains in the morning rush hour, officials say.<img height="150" width="201" alt="Emergency services carry a body from a Metro station in Moscow (29 March 2010)" src="http://wwwimg.bbc.co.uk/feedengine/homepage/images/_47550689_moscowap203_201x150.jpg">Twenty-three died in the first blast at 0756 (0356 GMT) as a<a href="#"> train stood </a>at the central Lubyanka station, beneath the offices of the FSB intelligence agency.About 40 minutes later, a second explosion ripped through a train at Park Kultury, leaving another 12 dead.No-one has said they carried out the worst attack in the capital since 2004. </p><p id="fbilisten"><a href="/go/homepage/i/int/news/heading/-/news/">More from BBC News</a></p></div> Thank you

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• a selector which has this selector together with a class selector

  - by Woho87

  Here is an analogy of my problem(a selector which has this selector together with a class selector): Let say that I selects all yellow(classes) div elements in a arbitrary HTML document. And I want each to check if the attribute is yes = 1. If the attribute 'yes' equals '1', then I want the child with class 'blue' have the attribute 'no' equals '1'; $('div .yellow').each(function(){ if($(this).attr('yes') == 1){ $(this '.blue:first-child').attr('no', 1);//This line needs to be fixed } }); I know that the line this.getElementsByClassName('blue')[0] fixes this problem. But in my real problem (not this analogy) I want to use addClass and removeClass which only functions with jQuery objects. It is to cumbersome to use other functions than addClass and removeClass. UPDATE: Here is a code snippet from my real problem. I got some problem with "this" in javascript. I want a invited button to have the className visible when I click on it. The button lies within a div element with className 'box'. I know that there are problem with 'this' on the code snippet. But I want the button and not the box to change to visible $('.Box').each(function(){ if($(this).attr('hasButton') != 1){ var invite = document.createElement('div'); invite.className = 'invite invisible'; invite.innerHTML = 'invite'; $(this).attr('hasButton', 1); this.appendChild(invite); invite.addEventListener('mouseover', function(event){ $('.invite', this).removeClass('invisible');//this line is not functioning $('.invite', this).addClass('visible');//neither this }, false); } });

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• Bored with CS. What can I study that will make an impact?

  - by Eric Martinez

  So I'm going to an average university, majoring in CS. I haven't learned a damn thing and am in my third year. I've come to be really bored with studying CS. Initially, I was kind of misinformed and thought majoring in CS would make me a good "product creator". I make my money combining programming and business/marketing. But I have always done programming for the love of the art. I find things like algorithms interesting and want to be able to use CS to solve real world problems. I like the idea of bioinformatics and other hybrid studies. I'm not good enough, yet I hope, to really make a significant effort in those areas but I aspire to be. What are some other fields, open problems, and otherwise cool stuff to apply CS knowledge to in the real world? I'm really looking for something that will motivate me and re-excite me to continue studying CS. Edit: Like someone mentioned below. I am very interesting in the idea of being able to use computer science to help answer fundamental questions of life and the universe. But I'm not sure what is possible or how to begin.

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• iTextSharp last version doesnot support metadata?

  - by zp chen

  Console.WriteLine("Chapter 1 example 6: Meta Information"); // step 1: creation of a document-object Document document = new Document(); try { // step 2: // we create a writer that listens to the document // and directs a PDF-stream to a file PdfWriter.GetInstance(document, new FileStream("Chap0106.pdf", FileMode.Create)); // step 3: we add some metadata and open the document document.AddTitle("Hello World example"); document.AddSubject("This example explains step 6 in Chapter 1"); document.AddKeywords("Metadata, iText, step 6, tutorial"); document.AddCreator("My program using iText#"); document.AddAuthor("Bruno Lowagie"); document.AddHeader("Expires", "0"); document.Open(); // step 4: we add a paragraph to the document document.Add(new Paragraph("Hello World")); } catch (DocumentException de) { Console.Error.WriteLine(de.Message); } catch (IOException ioe) { Console.Error.WriteLine(ioe.Message); } // step 5: we close the document document.Close(); I am just copy the iTextSharp.tutorial. I get the pdf file Chap0106.pdf but metadata show nothing... I am use vs2008 xp system

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• F# passing an operator with arguments to a function

  - by dan

  Can you pass in an operation like "divide by 2" or "subtract 1" using just a partially applied operator, where "add 1" looks like this: List.map ((+) 1) [1..5];; //equals [2..6] // instead of having to write: List.map (fun x-> x+1) [1..5] What's happening is 1 is being applied to (+) as it's first argument, and the list item is being applied as the second argument. For addition and multiplication, this argument ordering doesn't matter. Suppose I want to subtract 1 from every element (this will probably be a common beginners mistake): List.map ((-) 1) [1..5];; //equals [0 .. -4], the opposite of what we wanted 1 is applied to the (-) as its first argument, so instead of (list_item - 1), I get (1 - list_item). I can rewrite it as adding negative one instead of subtracting positive one: List.map ((+) -1) [1..5];; List.map (fun x -> x-1) [1..5];; // this works too I'm looking for a more expressive way to write it, something like ((-) _ 1), where _ denotes a placeholder, like in the Arc language. This would cause 1 to be the second argument to -, so in List.map, it would evaluate to list_item - 1. So if you wanted to map divide by 2 to the list, you could write: List.map ((/) _ 2) [2;4;6] //not real syntax, but would equal [1;2;3] List.map (fun x -> x/2) [2;4;6] //real syntax equivalent of the above Can this be done or do I have to use (fun x -> x/2)? It seems that the closest we can get to the placeholder syntax is to use a lambda with a named argument.

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• QT: custom widget in QScrollArea

  - by slimscsi

  I am attempting to create a custom widget. My Widget renders itself unless it is inside a scroll area. The code below works. If I change the if(0) to an if(1) inside the MainWindow constructor, it will not render the "Hello World" string. I assume that I must (re)implement some additional methods, but so far I have not been able to find the correct ones with trial and error. // hellowidget.h #ifndef HELLOWIDGET_H #define HELLOWIDGET_H #include <QtGui> class HelloWidget : public QWidget { Q_OBJECT public: HelloWidget(QWidget *parent = 0); void paintEvent(QPaintEvent *event); }; #endif // HELLOWIDGET_H // hellowidget.cpp #include "hellowidget.h" HelloWidget::HelloWidget(QWidget *parent) : QWidget(parent) { } void HelloWidget::paintEvent(QPaintEvent *event) { QPainter painter(this); painter.drawText(rect(), Qt::AlignCenter, "Hello World"); } // mainwindow.h #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QtGui> class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); private: }; #endif // MAINWINDOW_H // mainwindow.cpp #include "mainwindow.h" #include "hellowidget.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { HelloWidget *hello = new HelloWidget; QWidget *central = hello; if( 0 ) { QScrollArea *scroll = new QScrollArea ; scroll->setWidget(hello); central = scroll; } setCentralWidget( central ); } MainWindow::~MainWindow() { } // main.cpp #include <QtGui/QApplication> #include "mainwindow.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); return a.exec(); }

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• Dropping all user tables/sequences in Oracle

  - by Ambience

  As part of our build process and evolving database, I'm trying to create a script which will remove all of the tables and sequences for a user. I don't want to do recreate the user as this will require more permissions than allowed. My script creates a procedure to drop the tables/sequences, executes the procedure, and then drops the procedure. I'm executing the file from sqlplus: drop.sql: create or replace procedure drop_all_cdi_tables is cur integer; begin cur:= dbms_sql.OPEN_CURSOR(); for t in (select table_name from user_tables) loop execute immediate 'drop table ' ||t.table_name|| ' cascade constraints'; end loop; dbms_sql.close_cursor(cur); cur:= dbms_sql.OPEN_CURSOR(); for t in (select sequence_name from user_sequences) loop execute immediate 'drop sequence ' ||t.sequence_name; end loop; dbms_sql.close_cursor(cur); end; / execute drop_all_cdi_tables; / drop procedure drop_all_cdi_tables; / Unfortunately, dropping the procedure causes a problem. There seems to cause a race condition and the procedure is dropped before it executes. E.g.: SQL*Plus: Release 11.1.0.7.0 - Production on Tue Mar 30 18:45:42 2010 Copyright (c) 1982, 2008, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options Procedure created. PL/SQL procedure successfully completed. Procedure created. Procedure dropped. drop procedure drop_all_user_tables * ERROR at line 1: ORA-04043: object DROP_ALL_USER_TABLES does not exist SQL Disconnected from Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64 With the Partitioning, OLAP, Data Mining and Real Application Testing options Any ideas on how to get this working?

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• Tool for braceless, whitespace sensitive C syntax

  - by Ollie Saunders

  I'm writing some C at the moment and because I like whitespace sensitive syntax, I'd like to write it like this: #include <stdio.h> int main(void) printf("Hello, world!") return 0 Instead of this: #include <stdio.h> int main(void) { printf("Hello, world!"); return 0; } Does anybody know of a tool that will convert the former into the latter? Edit: I've really no interest in arguing with those that think this is a bad idea. By all means continue to think that, you have your reasons. But at least know this: I'm aware Python is a whitespace sensitive language but I have not used it. Why would I? I know Ruby already. Also know: I am not just learning C for the first time and I have used PHP and JavaScript for more than four years, so I am not requesting this out of some personal difficulty, lack of familiarity with block syntax, or dogmatic affiliation. I am also aware of what would be involved in writing one of these and that's not beyond my ability but I don't want this enough to justify spending the time writing one.

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• Rot13 for numbers.

  - by dreeves

  EDIT: Now a Major Motion Blog Post at http://messymatters.com/sealedbids The idea of rot13 is to obscure text, for example to prevent spoilers. It's not meant to be cryptographically secure but to simply make sure that only people who are sure they want to read it will read it. I'd like to do something similar for numbers, for an application involving sealed bids. Roughly I want to send someone my number and trust them to pick their own number, uninfluenced by mine, but then they should be able to reveal mine (purely client-side) when they're ready. They should not require further input from me or any third party. (Added: Note the assumption that the recipient is being trusted not to cheat.) It's not as simple as rot13 because certain numbers, like 1 and 2, will recur often enough that you might remember that, say, 34.2 is really 1. Here's what I'm looking for specifically: A function seal() that maps a real number to a real number (or a string). It should not be deterministic -- seal(7) should not map to the same thing every time. But the corresponding function unseal() should be deterministic -- unseal(seal(x)) should equal x for all x. I don't want seal or unseal to call any webservices or even get the system time (because I don't want to assume synchronized clocks). (Added: It's fine to assume that all bids will be less than some maximum, known to everyone, say a million.) Sanity check: > seal(7) 482.2382 # some random-seeming number or string. > seal(7) 71.9217 # a completely different random-seeming number or string. > unseal(seal(7)) 7 # we always recover the original number by unsealing.

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• Delphi, PGDac vs Zeos, Fetch, Lookup?

  - by durumdara

  Hi! I used Zeos to test to know: is ZTable uses fetch technics, or not? May in the future we migrate our lesser system to PGSQL, and this used now "Table" components (as BDE, but it have an SQL-like server). These tables use real cursors, a "Window" with N record, so lookup is very fast, because the Locate/Lookup is started on server, and only these N records are refreshed, no matter, how many records in the lookup table. PGSQL uses fetch technics as I know, and I tested it with a table (id int, name varchar(100)), and 1 million records. (I also trying this with mysql). The adapter is Zeos. ID, sec to find, allocated memory in bytes on client. MySQL 500000 2,761 113 196 344 1000000 3,214 225 471 232 313800 0,437 225 471 232 328066 0,468 225 471 232 276374 0,390 225 471 232 905984 1,264 225 471 232 260253 0,359 225 471 232 PGSQL 500000 3,042 113 188 184 1000000 3,744 225 463 064 313800 0,436 225 463 064 328066 0,452 225 463 064 276374 0,375 225 463 064 905984 1,295 225 463 064 260253 0,359 225 463 064 142023 0,203 225 463 064 As you see the records are fetched locally, this cause the 225 MB usage, and searches are slow a little, based where is the record we must find. I want to ask more things: a.) Is PGDAC have some technics to we can use the lookups without pay the fetch with memory and secs? b.) Or is PG ODBC driver can help in this problem with ADO? (As I know ADO can use server side cursors)? c.) Have anybody some experience with lookup tables, and performance? Is this critical question or it is not? (With client memory usage too). d.) If no chance to avoid fetch hell with lookups, what we can do? Server Side Joins, and unique code for Lookup field changing without real Lookup? Thanks for your help: dd

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• PHP gettext on Windows

  - by Axsuul

  There's some tutorials out there for gettext (w/ Poedit)... unfortunately, it's mostly for a UNIX environment. And even more unfortunate is that I am running my WAMP server on Windows XP (but I am developing for a UNIX environment) and none of the tutorials can get gettext working properly for me. From the man page (http://us3.php.net/manual/en/book.gettext.php), it appears that it's a different process on a Windows environment. I've tried out some of the solutions in the comments but I still can't get it to work! Please, I've spent many hours on this, hopefully someone can point me in the right direction to get this thing to work! (and I'm sure there are others out there who share my frustration). So far with my setup, I'm only getting output "Hello World!" whereas I should be getting the translated string. Here is my setup/code so far: <?php // test.php if (!defined('LC_MESSAGES')) { define('LC_MESSAGES', 6); } $locale = "deu_DEU"; // apparently the locales are different on a WINDOWS platform putenv("LC_ALL=$locale"); setlocale(LC_ALL, $locale); bindtextdomain("greetings", ".\locale"); textdomain("greetings"); echo _("Hello World"); ?> Folder structure root: C:\Program Files\WampServer 2\www test.php: C:\Program Files\WampServer 2\www\site .po: C:\Program Files\WampServer 2\www\site\locale\deu_DEU\LC_MESSAGES\greetings.po .mo: C:\Program Files\WampServer 2\www\site\locale\deu_DEU\LC_MESSAGES\greetings.mo Please advise! Thanks for your time :)

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• How to overload operator<< for qDebug

  - by iyo

  Hi, I'm trying to create more useful debug messages for my class where store data. My code is looking something like this #include <QAbstractTableModel> #include <QDebug> /** * Model for storing data. */ class DataModel : public QAbstractTableModel { // for debugging purposes friend QDebug & operator<< (const QDebug &d, DataModel model); //other stuff }; /** * Overloading operator for debugging purposes */ QDebug & operator<< (QDebug &d, DataModel model) { d << "Hello world!"; return d; } I expect qDebug() << model will print "Hello world!". However, there is alway something like "QAbstractTableModel(0x1c7e520)" on the output. Do you have any idea what's wrong?

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• Represent multiple Null/Generic objects in an ActiveRecord association?

  - by slothbear

  I have a Casefile model that belongs_to a Doctor. In additional to all the "real" doctors, there are several generic Doctors: "self-treated", "not specified", and "removed" (it used to have a real doctor, but no longer does). I suspect there will be even more generic values in the future. I started with special "doctors" in the database, generated from seed. The generic Doctors only need to respond to the "name" and "real_doctor?" methods. This worked with one, was strained with two, and now feels completely broken. I want to change the behavior and can't figure out how to test it, a bad sign. Creating all the generic objects for testing is also trouble, including fake values to pass validation of the required Doctor attributes. The Null Object pattern works well for one generic object. The "name" method could check casefile.doctor.nil? and return "self-treated", as demonstrated by Craig Ambrose. What pattern should I use when there are multiple generic objects with very limited state?

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• Is it just me? I find LINQ to XML to be sort of cumbersome, compared to XPath.

  - by Cheeso

  I am a C# programmer, so I don't get to take advantage of the cool XML syntax in VB. Dim itemList1 = From item In rss.<rss>.<channel>.<item> _ Where item.<description>.Value.Contains("LINQ") Or _ item.<title>.Value.Contains("LINQ") Using C#, I find XPath to be easier to think about, easier to code, easier to understand, than performing a multi-nested select using LINQ to XML. Look at this syntax, it looks like Greek swearing: var waypoints = from waypoint in gpxDoc.Descendants(gpx + "wpt") select new { Latitude = waypoint.Attribute("lat").Value, Longitude = waypoint.Attribute("lon").Value, Elevation = waypoint.Element(gpx + "ele") != null ? waypoint.Element(gpx + "ele").Value : null, Name = waypoint.Element(gpx + "name") != null ? waypoint.Element(gpx + "name").Value : null, Dt = waypoint.Element(gpx + "cmt") != null ? waypoint.Element(gpx + "cmt").Value : null }; All the casting, the heavy syntax, the possibility for NullPointerExceptions. None of this happens with XPath. I like LINQ in general, and I use it on object collections and databases, but my first go-round with querying XML led me right back to XPath. Is it just me? Am I missing something? EDIT: someone voted to close this as "not a real question". But it is a real question, stated clearly. The question is: Am I misunderstanding something with LINQ to XML?

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• How do I programmatically create a bootable CD?

  - by Nicholas Flynt

  I'm using a barebones tutorial as the basis for an OS I'm working on, and it seems to be an older tutorial: it has be compiling the kernel down to a floppy image, and then loading it with GRUB. Basically, I still want to use GRUB, but I'd like to have my OS run from a CD instead. The main reason is that I don't actually have a real floppy drive available (I'm testing in VirtualBox currently) and I thus have no way to test my OS on real hardware. I've been poking around on the net, and I can find lots of utilities that create a bootable CD from a floppy image, but these all seem to require an actual floppy drive, plus it's not really what I'm looking for. I'd like to be able to end up with a bootable CD during my make step ideally, without needing to first place the image on a floppy, which seems rather pointless. I guess the easy way to answer this: How do I set up GRUB to read my kernel image from a CD? Will I need a special utility to do this from Windows? (The kernel can't compile itself yet, that's not for a looong while) Thanks!

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• Use LaTeX Listings to correctly detect and syntax highlight embedded code of a different language in

  - by D W

  I have scripts that have one-liners or sort scripts from other languages within them. How can I have LaTeX listings detect this and change the syntax formating language withing the script? This would be especially useful for awk withing bash I believe. Bash #!/bin/bash ... # usage message to catch bad input without invoking R ... # any bash pre-processing of input ... # etc echo "hello world" R --vanilla << EOF # Data on motor octane ratings for various gasoline blends x <- c(88.5,87.7,83.4,86.7,87.5,91.5,88.6,100.3, 95.6,93.3,94.7,91.1,91.0,94.2,87.5,89.9, 88.3,87.6,84.3,86.7,88.2,90.8,88.3,98.8, 94.2,92.7,93.2,91.0,90.3,93.4,88.5,90.1, 89.2,88.3,85.3,87.9,88.6,90.9,89.0,96.1, 93.3,91.8,92.3,90.4,90.1,93.0,88.7,89.9, 89.8,89.6,87.4,88.9,91.2,89.3,94.4,92.7, 91.8,91.6,90.4,91.1,92.6,89.8,90.6,91.1, 90.4,89.3,89.7,90.3,91.6,90.5,93.7,92.7, 92.2,92.2,91.2,91.0,92.2,90.0,90.7) x length(x) mean(x);var(x) stem(x) EOF perl -n -e ' @t = split(/\t/); %t2 = map { $_ => 1 } split(/,/,$t[1]); $t[1] = join(",",keys %t2); print join("\t",@t); ' knownGeneFromUCSC.txt awk -F'\t' '{ n = split($2, t, ","); _2 = x split(x, _) # use delete _ if supported for (i = 0; ++i <= n;) _[t[i]]++ || _2 = _2 ? _2 "," t[i] : t[i] $2 = _2 }-3' OFS='\t' infile Python #!/usr/local/bin/python print "Hello World" os.system(""" VAR=even; sed -i "s/$VAR/odd/" testfile; for i in `cat testfile` ; do echo $i; done; echo "now the tr command is removing the vowels"; cat testfile |tr 'aeiou' ' ' """)

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• Prototype VS jQuery

  - by aSeptik

  Hi All guys! First of, thank's for your time; then i want go directly to the point by saying that, i don't want to open another "Yet Another Js VS Js" 3d , the web is almost busy of this! I want also make a premise, i have used both theese js frameworks and i love it and i know, that there are a lot of good js frameworks around, maybe better then this two; but, as you know we need to be perfomant and quickly by doing our works, so i want keep this two, that are the most famous and therefore have a great community support! now, if you are going to say me, that the choise depends on what i'm going to do!? then i can think, hey, in the end they are both javascript and they have almost the same methods and functions and for achieve a task they needs almost the same lines of code! So i want hear from you guys, from you that have really used one of theese, for a real Rich Internet Application what are the real points of force and what the weaknesses you find!? Regards.

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