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  • Need Help With This Simple Script (JavaScript Noob Question)

    - by three3
    Hi everyone, I am new to JavaScript (only a couple of days of reading a book) and I am stuck on this code snippet. I have looked at it over and over again but cannot seem to figure out why it is not working. I am sure it is something really simple that I have just looked over but I really just need a fresh pair of eyes to look at this. The code is supposed to update a placeholder image on a page without the page having to reload. But when I am clicking on the link of an image, it is taking me to the link where the image is located instead of replacing the placeholder image. Here is my HTML code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Image Gallery</title> <script type="text/javascript" src="scripts/showPic.js"></script> </head> <body> <h1>Snapshots</h1> <ul> <li> <a href="images/cat.jpg" onclick="showPic(this); return false;" title="A Cat">Cat</a> </li> <li> <a href="images/night.jpg" onclick="showPic(this); return false;" title="Night">Night</a> </li> <li> <a href="images/coke.jpg" onclick="showPic(this); return false;" title="Coke">Coke</a> </li> <li> <a href="images/sport.jpg" onclick="showPic(this); return false;" title="Sports">Sport</a> </li> <li> <a href="images/mnms.png" onclick="showPic(this); return false;" title="MnM's">MnM's</a> </li> <li> <a href="images/kid.jpg" onclick="showPic(this); return false;" title="A Kid">Kid</a> </li> </ul> <br /> <img src="images/placeholder.jpg" title="Place Holder Image"> </body> </html> And here is the JavaScript function I am using to get this done: <script type="text/javascript"> function showPic(whichpic) { var source = whichpic.getAttribute("href"); var placeholder = document.getElementById("placeholder"); placeholder.setAttribute("src",source); } </script> Any help is greatly appreciated and thanks in advance for the help.

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  • Simple show/hide jQuery troubles

    - by Banderdash
    Okay, I feel like a bit of a 800 pound gorilla trying to thread a needle when it comes to jQuery. I need a script that will preform a simple show/hide (preferably with a nice sliding in and out) on a list. My markup looks like this: <div id="themes"> <h2>Research Themes</h2> <ul> <li class="tier_1"><a href="">Learn about our approach to the <strong>environment</strong></a> <ul class="tier_2 hide"> <li><a href=""><em>How we are tying this all together</em></a></li> <li><a href=""><strong>Project:</strong> Solor Powered Biofactories</a></li> <li><a href=""><strong>Project:</strong> Cleaning Water with Nature</a></li> <li><a href=""><strong>Project:</strong> Higher Efficiency Solar Technology</a></li> </ul> </li> <li class="tier_1"><a href="">Learn about our approach to <strong>human health</strong></a> <ul class="tier_2 hide"> <li><a href="">Project name numero uno goes here</a></li> <li><a href="">Project name numero dos goes here</a></li> <li><a href="">Project name numero tres goes here</a></li> </ul> </li> <li class="tier_1"><a href="">Learn about our approach to <strong>national defense</strong></a> <ul class="tier_2 hide"> <li><a href="">Project name numero uno goes here</a></li> <li><a href="">Project name numero dos goes here</a></li> <li><a href="">Project name numero tres goes here</a></li> </ul> </li> </ul> </div><!-- // end themes --> You can see that each nested ul has a class of "tier_2" and "hide". Ideally when the li they are nested within ("li.tier_1") is clicked it's child ul will have the hide class removed and the li's contained within will slideout, but at the same time should check all the other ul.tier_2's and be sure they get a hide class--so only one theme can be expanded at a time. I set up a sandbox to try some things: http://jsbin.com/odete/3 My JS looks like this: $(function(){ $(".tier_1 a").each(function(i,o){ $(this).click(function(e){ e.preventDefault(); $(this).addClass("show").siblings("ul").removeClass("show"); $("ul.tier_2:eq("+i+")").show().siblings("ul.tier_2").hide(); }); }); }); Totally a dumb way to do this, I am sure. But I based it off another script and it does work "a little bit" as you can see in the sandbox. If one of you mean hands at jQuery might be so inclined to take a peek I'd be very grateful. If you could also advise on how to have the transitions slideIn and Out that would also be fantastic!

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  • Qwt plot not working , simple plot curve not appeat

    - by user1629213
    I followed the example of simple plot in qwt examples to plot a curve. The axis and the graph appear in the Qt main window user interface but the curve not. I assigned values to fit the curve but the curve not appear. Any suggestions and help how to solve the problem? Here is my code MainWindow::MainWindow( int argc, char** argv, QWidget *parent ) : QMainWindow( parent ) , qnode( argc,argv ) { ui.setupUi( this ); // Calling this incidentally connects all ui's triggers to on_...() callbacks in this class. QObject::connect( ui.actionAbout_Qt, SIGNAL( triggered( bool )), qApp, SLOT( aboutQt( ))); // qApp is a global variable for the application ReadSettings( ); setWindowIcon( QIcon( ":/images/icon.png" )); ui.tab_manager->setCurrentIndex( 0 ); // ensure the first tab is showing - qt-designer should have this already hardwired, but often loses it (settings?). QObject::connect( &qnode, SIGNAL( rosShutdown( )), this, SLOT( close( ))); /********************* ** Logging **********************/ ui.view_logging->setModel( qnode.loggingModel( )); QObject::connect( &qnode, SIGNAL( loggingUpdated( )), this, SLOT( updateLoggingView( ))); QObject::connect( &qnode, SIGNAL( graphReceived( )), this, SLOT( onGraphReceived( ))); QObject::connect( &qnode, SIGNAL( parameterReceived( )), this, SLOT( onParameterReceived( ))); /********************* ** Auto Start **********************/ if ( ui.checkbox_remember_settings->isChecked( )) { on_button_connect_clicked( true ); } ui.parameters->setAttribute( Qt::WA_NoMousePropagation ); ui.parameters->setAttribute( Qt::WA_OpaquePaintEvent ); ui.plotgraph->setAttribute( Qt::WA_NoMousePropagation ); ui.plotgraph->setAttribute( Qt::WA_OpaquePaintEvent ); p_plot = new QwtPlot(ui.plotgraph); p_plot->setTitle( "Plot LinVel" ); p_plot->setCanvasBackground( Qt::white ); // Axis p_plot->setAxisTitle( QwtPlot::xBottom, "Time(sec)" ); p_plot->setAxisTitle( QwtPlot::yLeft, "Linear Velocity (m/sec)" ); p_plot->setAxisScale( QwtPlot::yLeft, 0.0, 10.0 ); p_plot->setAxisScale( QwtPlot::xBottom, 0.0, 50.0 ); p_plot->insertLegend( new QwtLegend() ); //samplingThread.start(); QwtPlotGrid *grid = new QwtPlotGrid(); grid->attach( p_plot ); curve = new QwtPlotCurve(); curve->setTitle( "Linear velocity" ); // Set curve styles curve->setPen( Qt::blue, 4 ), curve->setRenderHint( QwtPlotItem::RenderAntialiased, true ); QwtSymbol *symbol = new QwtSymbol( QwtSymbol::Ellipse, QBrush( Qt::yellow), QPen( Qt::red, 2 ), QSize( 8, 8 ) ); curve->setSymbol( symbol); // Assign values to the curve //curve->setSamples(ui.plotgraph.get_linv_g());//yaw_g,trav_g,wall_g; curve->attach( p_plot ); p_plot->resize( 600, 400 ); p_plot->show(); void MainWindow::onGraphReceived( ) { { QMutexLocker locker( &qnode.m_mutex ); } } void MainWindow::onParameterReceived( ) { { QMutexLocker locker( &qnode.m_mutex ); std::vector<double> p_ = qnode.get_parameters(); std::cout << p_[0]<<" "<<p_[1]<<" "<<p_[2]<<" "<<p_[3]<<" "<<p_[4] << std::endl; } } Any help?

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  • Error Loading Simple XML

    - by Rooneyl
    I have an xml document (generated from msword 2010), which I am trying to process using simple xml. Sample of xml: <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <w:document xmlns:wpc="http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:wp14="http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing" xmlns:wp="http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing" xmlns:w10="urn:schemas-microsoft-com:office:word" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" xmlns:w14="http://schemas.microsoft.com/office/word/2010/wordml" xmlns:wpg="http://schemas.microsoft.com/office/word/2010/wordprocessingGroup" xmlns:wpi="http://schemas.microsoft.com/office/word/2010/wordprocessingInk" xmlns:wne="http://schemas.microsoft.com/office/word/2006/wordml" xmlns:wps="http://schemas.microsoft.com/office/word/2010/wordprocessingShape" mc:Ignorable="w14 wp14"> <w:body> <w:p w:rsidR="005B1098" w:rsidRDefault="005B1098"/> <w:p w:rsidR="00F254A4" w:rsidRDefault="00F254A4"/> <w:p w:rsidR="00F254A4" w:rsidRPr="008475A1" w:rsidRDefault="00C15492" w:rsidP="008475A1"> <w:pPr> <w:jc w:val="center"/> <w:rPr> <w:b/> <w:sz w:val="44"/> <w:szCs w:val="44"/> </w:rPr> </w:pPr> <w:r w:rsidRPr="008475A1"> <w:rPr> <w:b/> <w:sz w:val="44"/> <w:szCs w:val="44"/> </w:rPr> <w:t>Test file</w:t> </w:r> </w:p> <w:p w:rsidR="00C15492" w:rsidRPr="008475A1" w:rsidRDefault="00C15492" w:rsidP="008475A1"> <w:pPr> <w:jc w:val="center"/> <w:rPr> <w:sz w:val="20"/> <w:szCs w:val="20"/> </w:rPr> </w:pPr> <w:r w:rsidRPr="008475A1"> <w:rPr> <w:sz w:val="20"/> <w:szCs w:val="20"/> </w:rPr> <w:t>another paragraph</w:t> </w:r> </w:p> </w:body> </w:document> I am trying to open it using: if(!$simple_xml = simplexml_load_file($content)){ trigger_error('Error reading XML file',E_USER_ERROR); } else { echo 'loaded'; } And get the error: Message: simplexml_load_file(): I/O warning : failed to load external entity " Test file another paragraph " Any ideas?

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  • Problem when trying to use simple Shaders + VBOs

    - by Mr.Gando
    Hello I'm trying to convert the following functions to a VBO based function for learning purposes, it displays a static texture on screen. I'm using OpenGL ES 2.0 with shaders on the iPhone (should be almost the same than regular OpenGL in this case), this is what I got working: //Works! - (void) drawAtPoint:(CGPoint)point depth:(CGFloat)depth { GLfloat coordinates[] = { 0, 1, 1, 1, 0, 0, 1, 0 }; GLfloat width = (GLfloat)_width * _maxS, height = (GLfloat)_height * _maxT; GLfloat vertices[] = { -width / 2 + point.x, -height / 2 + point.y, width / 2 + point.x, -height / 2 + point.y, -width / 2 + point.x, height / 2 + point.y, width / 2 + point.x, height / 2 + point.y, }; glBindTexture(GL_TEXTURE_2D, _name); //Attrib position and attrib_tex coord are handles for the shader attributes glVertexAttribPointer(ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices); glEnableVertexAttribArray(ATTRIB_POSITION); glVertexAttribPointer(ATTRIB_TEXCOORD, 2, GL_FLOAT, GL_FALSE, 0, coordinates); glEnableVertexAttribArray(ATTRIB_TEXCOORD); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); } I tried to do this to convert to a VBO however I don't see anything displaying on-screen with this version: //Doesn't display anything - (void) drawAtPoint:(CGPoint)point depth:(CGFloat)depth { GLfloat width = (GLfloat)_width * _maxS, height = (GLfloat)_height * _maxT; GLfloat position[] = { -width / 2 + point.x, -height / 2 + point.y, width / 2 + point.x, -height / 2 + point.y, -width / 2 + point.x, height / 2 + point.y, width / 2 + point.x, height / 2 + point.y, }; //Texture on-screen position ( each vertex is x,y in on-screen coords ) GLfloat coordinates[] = { 0, 1, 1, 1, 0, 0, 1, 0 }; // Texture coords from 0 to 1 glBindVertexArrayOES(vao); glGenVertexArraysOES(1, &vao); glGenBuffers(2, vbo); //Buffer 1 glBindBuffer(GL_ARRAY_BUFFER, vbo[0]); glBufferData(GL_ARRAY_BUFFER, 8 * sizeof(GLfloat), position, GL_STATIC_DRAW); glEnableVertexAttribArray(ATTRIB_POSITION); glVertexAttribPointer(ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, position); //Buffer 2 glBindBuffer(GL_ARRAY_BUFFER, vbo[1]); glBufferData(GL_ARRAY_BUFFER, 8 * sizeof(GLfloat), coordinates, GL_DYNAMIC_DRAW); glEnableVertexAttribArray(ATTRIB_TEXCOORD); glVertexAttribPointer(ATTRIB_TEXCOORD, 2, GL_FLOAT, GL_FALSE, 0, coordinates); //Draw glBindVertexArrayOES(vao); glBindTexture(GL_TEXTURE_2D, _name); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); } In both cases I'm using this simple Vertex Shader //Vertex Shader attribute vec2 position;//Bound to ATTRIB_POSITION attribute vec4 color; attribute vec2 texcoord;//Bound to ATTRIB_TEXCOORD varying vec2 texcoordVarying; uniform mat4 mvp; void main() { //You CAN'T use transpose before in glUniformMatrix4fv so... here it goes. gl_Position = mvp * vec4(position.x, position.y, 0.0, 1.0); texcoordVarying = texcoord; } The gl_Position is equal to product of mvp * vec4 because I'm simulating glOrthof in 2D with that mvp And this Fragment Shader //Fragment Shader uniform sampler2D sampler; varying mediump vec2 texcoordVarying; void main() { gl_FragColor = texture2D(sampler, texcoordVarying); } I really need help with this, maybe my shaders are wrong for the second case ? thanks in advance.

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  • Help with simple linux shell implementation

    - by nunos
    I am implementing a simple version of a linux shell in c. I have succesfully written the parser, but I am having some trouble forking out the child process. However, I think the problem is due to arrays, pointers and such, because just started C with this project and am not still very knowledgable with them. I am getting a segmentation fault and don't know where from. Any help is greatly appreciated. #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/wait.h> #include <sys/types.h> #define MAX_COMMAND_LENGTH 250 #define MAX_ARG_LENGTH 250 typedef enum {false, true} bool; typedef struct { char **arg; char *infile; char *outfile; int background; } Command_Info; int parse_cmd(char *cmd_line, Command_Info *cmd_info) { char *arg; char *args[MAX_ARG_LENGTH]; int i = 0; arg = strtok(cmd_line, " "); while (arg != NULL) { args[i] = arg; arg = strtok(NULL, " "); i++; } int num_elems = i; if (num_elems == 0) return -1; cmd_info->infile = NULL; cmd_info->outfile = NULL; cmd_info->background = 0; int iarg = 0; for (i = 0; i < num_elems-1; i++) { if (!strcmp(args[i], "<")) { if (args[i+1] != NULL) cmd_info->infile = args[++i]; else return -1; } else if (!strcmp(args[i], ">")) { if (args[i+1] != NULL) cmd_info->outfile = args[++i]; else return -1; } else cmd_info->arg[iarg++] = args[i]; } if (!strcmp(args[i], "&")) cmd_info->background = true; else cmd_info->arg[iarg++] = args[i]; cmd_info->arg[iarg] = NULL; return 0; } void print_cmd(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("infile=\"%s\"\n", cmd_info->infile); printf("outfile=\"%s\"\n", cmd_info->outfile); printf("background=\"%d\"\n", cmd_info->background); } void get_cmd(char* str) { fgets(str, MAX_COMMAND_LENGTH, stdin); str[strlen(str)-1] = '\0'; //apaga o '\n' do fim } pid_t exec_simple(Command_Info *cmd_info) { pid_t pid = fork(); if (pid < 0) { perror("Fork Error"); return -1; } if (pid == 0) { execvp(cmd_info->arg[0], cmd_info->arg); perror(cmd_info->arg[0]); exit(1); } return pid; } int main(int argc, char* argv[]) { while (true) { char cmd_line[MAX_COMMAND_LENGTH]; Command_Info cmd_info; printf(">>> "); get_cmd(cmd_line); if ( (parse_cmd(cmd_line, &cmd_info) == -1) ) return -1; parse_cmd(cmd_line, &cmd_info); if (!strcmp(cmd_info.arg[0], "exit")) exit(0); pid_t pid = exec_simple(&cmd_info); waitpid(pid, NULL, 0); } return 0; } Thanks.

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  • Simple Constructor With Initializer List? - C++

    - by Alex
    Hi all, below I've included my h file, and my problem is that the compiler is not liking my simple exception class's constructor's with initializer lists. It also is saying that string is undeclared identifier, even though I have #include <string> at the top of the h file. Do you see something I am doing wrong? For further explanation, this is one of my domain classes that I'm integrating into a wxWidgets GUI application on Windows. Thanks! Time.h #pragma once #include <string> #include <iostream> // global constants for use in calculation const int HOURS_TO_MINUTES = 60; const int MINUTES_TO_HOURS = 100; class Time { public: // default Time class constructor // initializes all vars to default values Time(void); // ComputeEndTime computes the new delivery end time // params - none // preconditions - vars will be error-free // postconditions - the correct end time will be returned as an int // returns an int int ComputeEndTime(); // GetStartTime is the getter for var startTime // params - none // returns an int int GetStartTime() { return startTime; } // GetEndTime is the getter for var endTime // params - none // returns an int int GetEndTime() { return endTime; } // GetTimeDiff is the getter for var timeDifference // params - none // returns a double double GetTimeDiff() { return timeDifference; } // SetStartTime is the setter for var startTime // params - an int // returns void void SetStartTime(int s) { startTime = s; } // SetEndTime is the setter for var endTime // params - an int // returns void void SetEndTime(int e) { endTime = e; } // SetTimeDiff is the setter for var timeDifference // params - a double // returns void void SetTimeDiff(double t) { timeDifference = t; } // destructor for Time class ~Time(void); private: int startTime; int endTime; double timeDifference; }; class HourOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type HourOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~HourOutOfRangeException() {} private: string message; }; class MinuteOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type MinuteOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~MinuteOutOfRangeException() {} private: string message; }; class PercentageOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type PercentageOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~PercentageOutOfRangeException() {} private: string message; }; class StartEndException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type StartEndException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~StartEndException() {} private: string message; };

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  • Very simple shopping cart, remove button

    - by Kynian
    Im writing sales software that will be walking through a set of pages and on certain pages there are items listed to sell and when you click buy it basically just passes a hidden variable to the next page to be set as a session variable, and then when you get to the end it call gets reported to a database. However my employer wanted me to include a shopping cart, and this shopping cart should display the item name, sku, and price of whatever you're buying, as well as a remove button so the person doing the script doesnt need to go back through the entire thing to remove one item. At the moment I have the cart set to display everything, which was fairly simple. but I cant figure out how to get the remove button to work. Here is the code for the shopping cart: $total = 0; //TEST CODE: $_SESSION['itemname-addon'] = "Test addon"; $_SESSION ['price-addon'] = 10.00; $_SESSION ['sku-addon'] = "1234h"; $_SESSION['itemname-addon1'] = "Test addon1"; $_SESSION ['price-addon1'] = 99.90; $_SESSION ['sku-addon1'] = "1111"; $_SESSION['itemname-addon2'] = "Test addon2"; $_SESSION ['price-addon2'] = 19.10; $_SESSION ['sku-addon2'] = "123"; //end test code $items = Array ( "0"=> Array ( "name" => $_SESSION['itemname-mo'], "price" => $_SESSION ['price-mo'], "sku" => $_SESSION ['sku-mo'] ), "1" => Array ( "name" => $_SESSION['itemname-addon'], "price" => $_SESSION ['price-addon'], "sku" => $_SESSION ['sku-addon'] ), "2" => Array ( "name" => $_SESSION['itemname-addon1'], "price" => $_SESSION ['price-addon1'], "sku" => $_SESSION ['sku-addon1'] ), "3" => Array ( "name" => $_SESSION['itemname-addon2'], "price" => $_SESSION ['price-addon2'], "sku" => $_SESSION ['sku-addon2'] ) ); $a_length = count($items); for($x = 0; $x<$a_length; $x++){ $total +=$items[$x]['price']; } $formattedtotal = number_format($total,2,'.',''); for($i = 0; $i < $a_length; $i++){ $name = $items[$i]['name']; $price = $items[$i]['price']; $sku = $items[$i]['sku']; displaycart($name,$price,$sku); } echo "<br /> <b>Sub Total:</b> $$formattedtotal"; function displaycart($name,$price,$sku){ if($name != null || $price != null || $sku != null){ if ($name == "no sale" || $price == "no sale" || $sku == "no sale"){ echo ""; } else{ $formattedprice = number_format($price,2,'.',''); echo "$name: $$formattedprice ($sku)"; echo "<form action=\"\" method=\"post\">"; echo "<button type=\"submit\" />Remove</button><br />"; echo "</form>"; } } } So at this point Im not sure where to go from here for the remove button. Any suggestions would be appreciated.

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  • How can I make the storage of C++ lambda objects more efficient?

    - by Peter Ruderman
    I've been thinking about storing C++ lambda's lately. The standard advice you see on the Internet is to store the lambda in a std::function object. However, none of this advice ever considers the storage implications. It occurred to me that there must be some seriously black voodoo going on behind the scenes to make this work. Consider the following class that stores an integer value: class Simple { public: Simple( int value ) { puts( "Constructing simple!" ); this->value = value; } Simple( const Simple& rhs ) { puts( "Copying simple!" ); this->value = rhs.value; } Simple( Simple&& rhs ) { puts( "Moving simple!" ); this->value = rhs.value; } ~Simple() { puts( "Destroying simple!" ); } int Get() const { return this->value; } private: int value; }; Now, consider this simple program: int main() { Simple test( 5 ); std::function<int ()> f = [test] () { return test.Get(); }; printf( "%d\n", f() ); } This is the output I would hope to see from this program: Constructing simple! Copying simple! Moving simple! Destroying simple! 5 Destroying simple! Destroying simple! First, we create the value test. We create a local copy on the stack for the temporary lambda object. We then move the temporary lambda object into memory allocated by std::function. We destroy the temporary lambda. We print our output. We destroy the std::function. And finally, we destroy the test object. Needless to say, this is not what I see. When I compile this on Visual C++ 2010 (release or debug mode), I get this output: Constructing simple! Copying simple! Copying simple! Copying simple! Copying simple! Destroying simple! Destroying simple! Destroying simple! 5 Destroying simple! Destroying simple! Holy crap that's inefficient! Not only did the compiler fail to use my move constructor, but it generated and destroyed two apparently superfluous copies of the lambda during the assignment. So, here finally are the questions: (1) Is all this copying really necessary? (2) Is there some way to coerce the compiler into generating better code? Thanks for reading!

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  • Simple syntax error still eluding me.

    - by melee
    Here is the header for a class I started: #ifndef CANVAS_ #define CANVAS_ #include <iostream> #include <iomanip> #include <string> #include <stack> class Canvas { public: Canvas(); void Paint(int R, int C, char Color); const int Nrow; const int Ncol; string Title; int image[][100]; stack<int> path; struct PixelCoordinates { unsigned int r; unsigned int c; } position; Canvas operator<< (const Canvas& One ); Canvas operator>>( Canvas& One ); }; /*----------------------------------------------------------------------------- Name: operator<< Purpose: Put a Canvas into an output stream -----------------------------------------------------------------------------*/ ostream& operator<<( ostream& Out, const Canvas& One ) { Out << One.Title << endl; Out << "Rows: " << One.Nrow << " Columns: " << One.Ncol << endl; int i,j; for( i=0; i<One.Nrow; i++) { cout<<"\n\n\n"; cout<< " COLUMN\n"; cout<< " 1 2 3"; for(i=0;i<One.Nrow;i++) { cout<<"\nROW "<<i+1; for(j=0;j<One.Ncol;j++) cout<< One.image[i][j]; } } return Out; } /*----------------------------------------------------------------------------- Name: operator>> Purpose: Get a Canvas from an input stream -----------------------------------------------------------------------------*/ istream& operator>>( istream& In, Canvas& One ) { // string Line; // int Place = 0; // { // In >> Line; // if (In.good()) // { // One.image[Place][0] = Line; // Place++; // } // return In; #endif Here is my implementation file for class Canvas: using namespace std; #include <iostream> #include <iomanip> #include <string> #include <stack> #include "proj05.canvas.h" //----------------Constructor----------------// Canvas::Canvas() { Title = ""; Nrow = 0; Ncol = 0; image[][100] = {}; position.r = 0; position.c = 0; } //-------------------Paint------------------// void Canvas::Paint(int R, int C, char Color) { cout << "Paint to be implemented" << endl; } And the errors I'm getting are these: proj05.canvas.cpp: In function 'std::istream& operator>>(std::istream&, Canvas&)': proj05.canvas.cpp:11: error: expected `;' before '{' token proj05.canvas.cpp:24: error: expected `}' at end of input From my limited experience, they look like simple syntax errors but for the life of me, I cannot see what I am missing. I know putting a ; at the end of Canvas::Canvas() is wrong but that seems to be what it expects. Could someone please clarify for me? (Also, I know much of the code for the << and operator definitions look terrible, but unless that is the specific reason for the error please do not address it. This is a draft :) )

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  • Simple prime number program - Weird issue with threads C#

    - by Para
    Hi! This is my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace FirePrime { class Program { static bool[] ThreadsFinished; static bool[] nums; static bool AllThreadsFinished() { bool allThreadsFinished = false; foreach (var threadFinished in ThreadsFinished) { allThreadsFinished &= threadFinished; } return allThreadsFinished; } static bool isPrime(int n) { if (n < 2) { return false; } if (n == 2) { return true; } if (n % 2 == 0) { return false; } int d = 3; while (d * d <= n) { if (n % d == 0) { return false; } d += 2; } return true; } static void MarkPrimes(int startNumber,int stopNumber,int ThreadNr) { for (int j = startNumber; j < stopNumber; j++) nums[j] = isPrime(j); lock (typeof(Program)) { ThreadsFinished[ThreadNr] = true; } } static void Main(string[] args) { int nrNums = 100; int nrThreads = 10; //var threadStartNums = new List<int>(); ThreadsFinished = new bool[nrThreads]; nums = new bool[nrNums]; //var nums = new List<bool>(); nums[0] = false; nums[1] = false; for(int i=2;i<nrNums;i++) nums[i] = true; int interval = (int)(nrNums / nrThreads); //threadStartNums.Add(2); //int aux = firstStartNum; //int i = 2; //while (aux < interval) //{ // aux = interval*i; // i=i+1; // threadStartNums.Add(aux); //} int startNum = 0; for (int i = 0; i < nrThreads; i++) { var _thread = new System.Threading.Thread(() => MarkPrimes(startNum, Math.Min(startNum + interval, nrNums), i)); startNum = startNum + interval; //set the thread to run in the background _thread.IsBackground = true; //start our thread _thread.Start(); } while (!AllThreadsFinished()) { Thread.Sleep(1); } for (int i = 0; i < nrNums; i++) if(nums[i]) Console.WriteLine(i); } } } This should be a pretty simple program that is supposed to find and output the first nrNums prime numbers using nrThreads threads working in parallel. So, I just split nrNums into nrThreads equal chunks (well, the last one won't be equal; if nrThreads doesn't divide by nrNums, it will also contain the remainder, of course). I start nrThreads threads. They all test each number in their respective chunk and see if it is prime or not; they mark everything out in a bool array that keeps a tab on all the primes. The threads all turn a specific element in another boolean array ThreadsFinished to true when they finish. Now the weird part begins: The threads never all end. If I debug, I find that ThreadNr is not what I assign to it in the loop but another value. I guess this is normal since the threads execute afterwards and the counter (the variable i) is already increased by then but I cannot understand how to make the code be right. Can anyone help? Thank you in advance. P.S.: I know the algorithm is not very efficient; I am aiming at a solution using the sieve of Eratosthenes also with x given threads. But for now I can't even get this one to work and I haven't found any examples of any implementations of that algorithm anywhere in a language that I can understand.

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  • Simple Adapter error

    - by Rahul Varma
    Hi, I have the following errors when i try to access the simple adapter from my program... Plz can anyone help me solving the error... Desperate to get it done.... android.widget.SimpleAdapter.getCount(SimpleAdapter.java:95) android.widget.ListView.setAdapter(ListView.java:431) com.stellent.gorinka.MusicListActivity.list(MusicListActivity.java:76) com.stellent.gorinka.MusicListActivity$1.run(MusicListActivity.java:67) android.os.Handler.handleCallback(Handler.java:587) android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:123) android.os.Handler.handleCallback(Handler.java:587) android.os.Handler.dispatchMessage(Handler.java:92) android.os.Looper.loop(Looper.java:123) Here' the code for Adapter... public class SongsAdapter extends SimpleAdapter{ static List<HashMap<String,String>> songsList; Context context; LayoutInflater inflater; public SongsAdapter(Context context,List<HashMap<String,String>> imgListWeb,int layout,String[] from,int[] to,LayoutInflater inflater) { super(context,songsList,layout,from,to); this.songsList=songsList; this.context=context; this.inflater=inflater; // TODO Auto-generated constructor stub }@Override public View getView(int postition,View convertView,ViewGroup parent)throws java.lang.OutOfMemoryError{ try { View v = ((LayoutInflater) inflater).inflate(R.layout.row,null); ImageView images=(ImageView)v.findViewById(R.id.image); TextView tvTitle=(TextView)v.findViewById(R.id.text1); TextView tvAlbum=(TextView)v.findViewById(R.id.text2); TextView tvArtist=(TextView)v.findViewById(R.id.text3); HashMap<String,String> songsHash=songsList.get(postition); String path=songsHash.get("path"); String title=songsHash.get("title"); String album=songsHash.get("album"); String artist=songsHash.get("artist"); String imgPath=path; final ImageView imageView = (ImageView) v.findViewById(R.id.image); AsyncImageLoaderv asyncImageLoader=new AsyncImageLoaderv(); Bitmap cachedImage = asyncImageLoader.loadDrawable(imgPath, new AsyncImageLoaderv.ImageCallback() { public void imageLoaded(Bitmap imageDrawable, String imageUrl) { imageView.setImageBitmap(imageDrawable); } }); imageView.setImageBitmap(cachedImage); tvTitle.setText(title); tvAlbum.setText(album); tvArtist.setText(artist); return v; } catch(Exception e){ Log.e("error",e.toString()); } return null; } And also in my main program the focus is not entering the loop... The implementation in the loop isnt getting executed...Here's the code for it... public void list() { Log.d("#####","#####"); LayoutInflater inflater=getLayoutInflater(); String[] from={}; int[] n={}; adapter=new SongsAdapter(getApplicationContext(),songNodeDet,R.layout.row,from,n,inflater); lv.setAdapter(adapter);} private Handler handler = new Handler() { public void handleMessage(Message msg){ Log.d("*****","handler"); removeDialog(0); p.dismiss(); } }; public void webObjectList(Object[] imgListObj,String logInSess) throws XMLRPCException{ songNodeWeb = new HashMap<?,?>[imgListObj.length]; if(imgListObj!=null){ Log.e("completed","completed"); for(int i=0;i<imgListObj.length;i++){ //imgListObj.length songNodeWeb[i]=(HashMap<?,?>)imgListObj[i]; String nodeid=(String) songNodeWeb[i].get("nid"); Log.e("img",i+"completed"); HashMap<String,String> nData=new HashMap<String,String>(); nData.put("nid",nodeid); Object nodeget=client.call("node.get",logInSess,nodeid); HashMap<?,?> imgNode=(HashMap<?,?>)nodeget; String titleName=(String) imgNode.get("titles"); String movieName=(String) imgNode.get("album"); String singerName=(String) imgNode.get("artist"); nData.put("titles", titleName); nData.put("album", movieName); nData.put("artist", singerName); Object[] imgObject=(Object[])imgNode.get("title_format"); HashMap<?,?>[] imgDetails=new HashMap<?,?>[imgObject.length]; imgDetails[0]=(HashMap<?, ?>)imgObject[0]; String path=(String) imgDetails[0].get("filepath"); if(path.contains(" ")){ path=path.replace(" ", "%20"); } String imgPath="http://www.gorinka.com/"+path; paths.add(imgPath); nData.put("path", imgPath); Log.e("my path",path); String mime=(String)imgDetails[0].get("filemime"); nData.put("mime", mime); SongsList songs=new SongsList(titleName,movieName,singerName,imgPath,imgPath); SngList.add(i,songs); songNodeDet.add(i,nData); } Log.e("paths values",paths.toString()); // return imgNodeDet; handler.sendEmptyMessage(0); } } public void getSongs() throws MalformedURLException, XMLRPCException { String ur="http://www.gorinka.com/?q=services/xmlrpc"; URL u=new URL(ur); client = new XMLRPCClient(u); //Connecting to the website HashMap<?, ?> siteConn =(HashMap<?, ?>) client.call("system.connect"); // Getting initial sessio id String initSess=(String)siteConn.get("sessid"); //Login to the site using session id HashMap<?, ?> logInConn =(HashMap<?, ?>) client.call("user.login",initSess,"prakash","stellentsoft2009"); //Getting Login sessid logInSess=(String)logInConn.get("sessid"); websongListObject =(Object[]) client.call("nodetype.get",logInSess,""); webObjectList(websongListObject,logInSess); Log.d("webObjectList","webObjectList"); runOnUiThread(returnRes); } }

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  • Simple Grouping With TableSorter Plugin

    - by HurnsMobile
    Im playing around with the Tablesorter plug-in for jQuery and was trying to get a very simple grouping functionality added into it. Using the follow html/js works great until you click sort again and reverse the order. The headers get moved to the bottom of the group when this happens. The following is my (admitedly hacky) attempt at it. Does anyone have any ideas? <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Table Manipulation Test</title> <link type="text/css" href="css/ui-lightness/jquery-ui-1.8.1.custom.css" rel="stylesheet" /> <link rel="stylesheet" href="tablesorter/themes/green/style.css" type="text/css"/> <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script> <script type="text/javascript" src="js/jquery-ui-1.8.1.custom.min.js"></script> <script type="text/javascript" src="tablesorter/jquery.tablesorter.min.js"></script> <script type="text/javascript"> $(document).ready(function() { $("#test_table").tablesorter({ sortForce: [[3,0]] }); $(".group_details").hide(); $(".group_header").click(function(){ var group = $(this).attr("group"); var $expander = $(this).children("td.expanderguy") if ($("." + group + ":visible").length){ $("." + group + "").fadeOut('fast'); $expander.html("<img src='icons/plus.gif'>"); } else{ $("." + group + "").fadeIn('fast'); $expander.html("<img src='icons/minus.gif'>"); } }); } ); </script> <style type="text/css"> .group_header td{ background-color: #888888; !important } </style> </head> <body> <table id="test_table" class="tablesorter"> <thead> <tr><th>First Name</th><th>Last Name</th><th>Email</th><th>Due Date</th><th>Amount Due</th></tr> </thead> <tbody> <tr class="group_header" group="group1"><td class="expanderguy"><img src="icons/plus.gif"></td><td></td><td></td><td>Monday, June 7</td><td></td></tr> <tr class="group_details group1"><td>Flavian</td><td>Wenceslas</td><td>[email protected]</td><td>Monday, June 7</td><td>$100</td></tr> <tr class="group_details group1"><td>Gordian</td><td>Ives</td><td>[email protected]</td><td>Monday, June 7</td><td>$1700</td></tr> <tr class="group_details group1"><td>Saladin</td><td>Tarquin</td><td>[email protected]</td><td>Monday, June 7</td><td>$1700</td></tr> <tr class="group_details group1"><td>Urban</td><td>Cyprian</td><td>[email protected]</td><td>Monday, June 7</td><td>$1500</td></tr> <tr class="group_details group1"><td>Sargon</td><td>Swithun</td><td>[email protected]</td><td>Monday, June 7</td><td>$1100</td></tr> <tr class="group_details group1"><td>Pompey</td><td>Ladislas</td><td>[email protected]</td><td>Monday, June 7</td><td>$300</td></tr> <tr class="group_details group1"><td>Attila</td><td>Hiawatha</td><td>[email protected]</td><td>Monday, June 7</td><td>$200</td></tr> <tr class="group_header" group="group2"><td class="expanderguy"><img src="icons/plus.gif"></td><td></td><td></td><td>Tuesday, June 8</td><td></td></tr> <tr class="group_details group2"><td>Bruce</td><td>Fenton</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$1700</td></tr> <tr class="group_details group2"><td>Wade</td><td>Sequoia</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$1400</td></tr> <tr class="group_details group2"><td>Eddie</td><td>Jerold</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$1100</td></tr> <tr class="group_details group2"><td>Lynn</td><td>Lucan</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$1200</td></tr> <tr class="group_details group2"><td>Taegan</td><td>Tadg</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$100</td></tr> <tr class="group_details group2"><td>Clyde</td><td>Reed</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$6100</td></tr> <tr class="group_details group2"><td>Alaois</td><td>Art</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$2100</td></tr> <tr class="group_details group2"><td>Gilbert</td><td>Patsy</td><td>[email protected]</td><td>Tuesday, June 8</td><td>$1500</td></tr> <tr class="group_header" group="group3"><td class="expanderguy"><img src="icons/plus.gif"></td><td></td><td></td><td>Wednesday, June 9</td><td></td></tr> <tr class="group_details group3" ><td>Clem</td><td>Eben</td><td>[email protected]</td><td>Wednesday, June 9</td><td>$2100</td></tr> <tr class="group_details group3" ><td>Elijah</td><td>Julyan</td><td>[email protected]</td><td>Wednesday, June 9</td><td>$2100</td></tr> <tr class="group_details group3" ><td>Marvyn</td><td>Damian</td><td>[email protected]</td><td>Wednesday, June 9</td><td>$1100</td></tr> <tr class="group_details group3" ><td>Sawyer</td><td>Ryker</td><td>[email protected]</td><td>Wednesday, June 9</td><td>$500</td></tr> </tbody> </table> </body>

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  • Ask the Readers: How Do You Keep Your Email SPAM Free and Tidy?

    - by Jason Fitzpatrick
    Email can be a fantastically efficient way to deal with communication, but not if it’s bogged down with SPAM messages and poorly organized. This week we want to hear all about the tips, tricks, and ninja-filters you use to keep your inbox tidy. Whether it’s special filters for your Bacon (spam-like marketing that you actually want to receive and occasional review), services you use to block spammers, or organization tips you use to keep your email inbox streamlined with no message unreplied to, we want to hear all about it. Sound off in the comments with your proclamations of your inbox-fu and how you maintain zen-like mastery over your email workflow. Be sure to check in on Friday for the What You Said roundup. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • How can I keep track of all the websites I've made like a proper business would?

    - by Mile
    A few other students and I are forming a group that wants to become good at what we do: websites. We are making websites for free for friends at the moment in order to get ourselves some experience and to learn from each other. We are about to finish our first website this week. In 6 months time we plan to have a portfolio and hope to start charging for websites. The issue is that we are all beginners and we are unsure about how to keep records of the websites we do. It is important as we may want to maintain a few websites or add to them later on. How does a proper web design business keep records of all info needed? Is there a program or software package we can use?

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  • Keep Learning After Your Oracle Training Class is Over - Save 50%!

    - by KJones
    Written by Amit Kumar, Senior Director Oracle University Digital Training        Every training class you take about the latest Oracle application or technology moves you closer to developing the skills you need to succeed. But after class is over, how do you keep up with today’s accelerating pace of innovation? To   To keep with the very latest technological advances, you need an ongoing and flexible training solution.       One that lets you learn during your own downtime.       Knowledge that’s easy to access.       Interactive lessons where you connect with experts.       A simple way to increase your knowledge, on your own time and at your own pace. The new Oracle Learning Streams is the flexible training solution you're looking for. Continuously Learn with Oracle Learning Streams Over time, Oracle Learning Streams help you develop the depth and breadth of knowledge that will give you the tools to become an expert in your field. By taking advantage of comprehensive and frequently updated information, you can keep learning continuously, at your own pace, when it's convenient for you. Sign up today and get 12 months of unlimited access to: •    Hundreds of videos delivered by Oracle experts for fresh and continuous product learning•    Live connections with Oracle's top instructors•    Robust video search capability to find exactly what you’re looking for•    Features that allow you to build your own custom learning queue and request new content Oracle Learning Streams are now available for Oracle Database and Oracle Middleware. Take a moment to preview the content now.  For a Limited Time - Save 50% For a limited time, save 50% when you order Oracle Learning Streams with any other Oracle Classroom, Live Virtual Class or Training On Demand course. Now there is no reason for learning to stop when class is over!

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  • How do I keep the Thunderbird profile in sync between multiple computers?

    - by David Planella
    I'd like to find a definitive solution to automatically keep my Thunderbird profile in sync between my laptop and my desktop computer. I'm using IMAP, so keeping the e-mail itself in sync is not an issue I can use Ubuntu One for the contacts, so that should not be an issue, either. However, there are a bunch of other files and folders in the Thunderbird profile, and I'm not sure which ones I should keep in sync and which ones I shouldn't bother about. Ideally, I'd like to use Ubuntu One to mark the required ones for syncing, but I would appreciate any help in deciding which ones exactly need to be synced.

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  • How can I keep track of a battle log on a web game?

    - by Jay W
    Recently I started working on a Web turn-based PvP RPG game. Now I'm working on the battle system but I encountered some issues: How can I keep track of everything that happens in the battle? It should keep track of the characters on the field, inventory, the damage done etc. I first thought I would simply put it in the (MySQL) database, but I think it will be too much. Especially if several people are in a battle. I thought of puting this in sessions or cookies but I don't think thats reliable. Does anyone have an idea how I can do this?

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  • how do i delete an icon from the desktop but keep it on the luncher?

    - by user210383
    how do i delete an icon from the desktop but keep it on the luncher? i installed steam and the program created two icons one in the luncher and one on the desktop. when i try to delete the one on the desktop the other one is also deleted. i only want to keep the one on the luncher. also the version is 12.04. i am a fist time user of Ubuntu and it seems confusing some times. if you can help thank you in advance.

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  • Is it good practice to keep 2 related tables (using auto_increment PK) to have the same Max of auto_increment ID when table1 got modified?

    - by Tum
    This question is about good design practice in programming. Let see this example, we have 2 interrelated tables: Table1 textID - text 1 - love.. 2 - men... ... Table2 rID - textID 1 - 1 2 - 2 ... Note: In Table1: textID is auto_increment primary key In Table2: rID is auto_increment primary key & textID is foreign key The relationship is that 1 rID will have 1 and only 1 textID but 1 textID can have a few rID. So, when table1 got modification then table2 should be updated accordingly. Ok, here is a fictitious example. You build a very complicated system. When you modify 1 record in table1, you need to keep track of the related record in table2. To keep track, you can do like this: Option 1: When you modify a record in table1, you will try to modify a related record in table 2. This could be quite hard in term of programming expecially for a very very complicated system. Option 2: instead of modifying a related record in table2, you decided to delete old record in table 2 & insert new one. This is easier for you to program. For example, suppose you are using option2, then when you modify record 1,2,3,....,100 in table1, the table2 will look like this: Table2 rID - textID 101 - 1 102 - 2 ... 200 - 100 This means the Max of auto_increment IDs in table1 is still the same (100) but the Max of auto_increment IDs in table2 already reached 200. what if the user modify many times? if they do then the table2 may run out of records? we can use BigInt but that make the app run slower? Note: If you spend time to program to modify records in table2 when table1 got modified then it will be very hard & thus it will be error prone. But if you just clear the old record & insert new records into table2 then it is much easy to program & thus your program is simpler & less error prone. So, is it good practice to keep 2 related tables (using auto_increment PK) to have the same Max of auto_increment ID when table1 got modified?

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  • Query on simple C++ threadpool implementation

    - by ticketman
    Stackoverflow has been a tremendous help to me and I'd to give something back to the community. I have been implementing a simple threadpool using the tinythread C++ portable thread library, using what I have learnt from Stackoverflow. I am new to thread programming, so not that comfortable with mutexes, etc. I have a question best asked after presenting the code (which runs quite well under Linux): // ThreadPool.h class ThreadPool { public: ThreadPool(); ~ThreadPool(); // Creates a pool of threads and gets them ready to be used void CreateThreads(int numOfThreads); // Assigns a job to a thread in the pool, but doesn't start the job // Each SubmitJob call will use up one thread of the pool. // This operation can only be undone by calling StartJobs and // then waiting for the jobs to complete. On completion, // new jobs may be submitted. void SubmitJob( void (*workFunc)(void *), void *workData ); // Begins execution of all the jobs in the pool. void StartJobs(); // Waits until all jobs have completed. // The wait will block the caller. // On completion, new jobs may be submitted. void WaitForJobsToComplete(); private: enum typeOfWorkEnum { e_work, e_quit }; class ThreadData { public: bool ready; // thread has been created and is ready for work bool haveWorkToDo; typeOfWorkEnum typeOfWork; // Pointer to the work function each thread has to call. void (*workFunc)(void *); // Pointer to work data void *workData; ThreadData() : ready(false), haveWorkToDo(false) { }; }; struct ThreadArgStruct { ThreadPool *threadPoolInstance; int threadId; }; // Data for each thread ThreadData *m_ThreadData; ThreadPool(ThreadPool const&); // copy ctor hidden ThreadPool& operator=(ThreadPool const&); // assign op. hidden // Static function that provides the function pointer that a thread can call // By including the ThreadPool instance in the void * parameter, // we can use it to access other data and methods in the ThreadPool instance. static void ThreadFuncWrapper(void *arg) { ThreadArgStruct *threadArg = static_cast<ThreadArgStruct *>(arg); threadArg->threadPoolInstance->ThreadFunc(threadArg->threadId); } // The function each thread calls void ThreadFunc( int threadId ); // Called by the thread pool destructor void DestroyThreadPool(); // Total number of threads available // (fixed on creation of thread pool) int m_numOfThreads; int m_NumOfThreadsDoingWork; int m_NumOfThreadsGivenJobs; // List of threads std::vector<tthread::thread *> m_ThreadList; // Condition variable to signal each thread has been created and executing tthread::mutex m_ThreadReady_mutex; tthread::condition_variable m_ThreadReady_condvar; // Condition variable to signal each thread to start work tthread::mutex m_WorkToDo_mutex; tthread::condition_variable m_WorkToDo_condvar; // Condition variable to signal the main thread that // all threads in the pool have completed their work tthread::mutex m_WorkCompleted_mutex; tthread::condition_variable m_WorkCompleted_condvar; }; cpp file: // // ThreadPool.cpp // #include "ThreadPool.h" // This is the thread function for each thread. // All threads remain in this function until // they are asked to quit, which only happens // when terminating the thread pool. void ThreadPool::ThreadFunc( int threadId ) { ThreadData *myThreadData = &m_ThreadData[threadId]; std::cout << "Hello world: Thread " << threadId << std::endl; // Signal that this thread is ready m_ThreadReady_mutex.lock(); myThreadData->ready = true; m_ThreadReady_condvar.notify_one(); // notify the main thread m_ThreadReady_mutex.unlock(); while(true) { //tthread::lock_guard<tthread::mutex> guard(m); m_WorkToDo_mutex.lock(); while(!myThreadData->haveWorkToDo) // check for work to do m_WorkToDo_condvar.wait(m_WorkToDo_mutex); // if no work, wait here myThreadData->haveWorkToDo = false; // need to do this before unlocking the mutex m_WorkToDo_mutex.unlock(); // Do the work switch(myThreadData->typeOfWork) { case e_work: std::cout << "Thread " << threadId << ": Woken with work to do\n"; // Do work myThreadData->workFunc(myThreadData->workData); std::cout << "#Thread " << threadId << ": Work is completed\n"; break; case e_quit: std::cout << "Thread " << threadId << ": Asked to quit\n"; return; // ends the thread } // Now to signal the main thread that my work is completed m_WorkCompleted_mutex.lock(); m_NumOfThreadsDoingWork--; // Unsure if this 'if' would make the program more efficient // if(NumOfThreadsDoingWork == 0) m_WorkCompleted_condvar.notify_one(); // notify the main thread m_WorkCompleted_mutex.unlock(); } } ThreadPool::ThreadPool() { m_numOfThreads = 0; m_NumOfThreadsDoingWork = 0; m_NumOfThreadsGivenJobs = 0; } ThreadPool::~ThreadPool() { if(m_numOfThreads) { DestroyThreadPool(); delete [] m_ThreadData; } } void ThreadPool::CreateThreads(int numOfThreads) { // Check a thread pool has already been created if(m_numOfThreads > 0) return; m_NumOfThreadsGivenJobs = 0; m_NumOfThreadsDoingWork = 0; m_numOfThreads = numOfThreads; m_ThreadData = new ThreadData[m_numOfThreads]; ThreadArgStruct threadArg; for(int i=0; i<m_numOfThreads; ++i) { threadArg.threadId = i; threadArg.threadPoolInstance = this; // Creates the thread and save in a list so we can destroy it later m_ThreadList.push_back( new tthread::thread( ThreadFuncWrapper, (void *)&threadArg ) ); // It takes a little time for a thread to get established. // Best wait until it gets established before creating the next thread. m_ThreadReady_mutex.lock(); while(!m_ThreadData[i].ready) // Check if thread is ready m_ThreadReady_condvar.wait(m_ThreadReady_mutex); // If not, wait here m_ThreadReady_mutex.unlock(); } } // Adds a job to the batch, but doesn't start the job void ThreadPool::SubmitJob(void (*workFunc)(void *), void *workData) { // Check that the thread pool has been created if(!m_numOfThreads) return; if(m_NumOfThreadsGivenJobs >= m_numOfThreads) return; m_ThreadData[m_NumOfThreadsGivenJobs].workFunc = workFunc; m_ThreadData[m_NumOfThreadsGivenJobs].workData = workData; std::cout << "Submitted job " << m_NumOfThreadsGivenJobs << std::endl; m_NumOfThreadsGivenJobs++; } void ThreadPool::StartJobs() { // Check that the thread pool has been created // and some jobs have been assigned if(!m_numOfThreads || !m_NumOfThreadsGivenJobs) return; // Set 'haveworkToDo' flag for all threads m_WorkToDo_mutex.lock(); for(int i=0; i<m_NumOfThreadsGivenJobs; ++i) m_ThreadData[i].haveWorkToDo = true; m_NumOfThreadsDoingWork = m_NumOfThreadsGivenJobs; // Reset this counter so we can resubmit jobs later m_NumOfThreadsGivenJobs = 0; // Notify all threads they have work to do m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); } void ThreadPool::WaitForJobsToComplete() { // Check that a thread pool has been created if(!m_numOfThreads) return; m_WorkCompleted_mutex.lock(); while(m_NumOfThreadsDoingWork > 0) // Check if all threads have completed their work m_WorkCompleted_condvar.wait(m_WorkCompleted_mutex); // If not, wait here m_WorkCompleted_mutex.unlock(); } void ThreadPool::DestroyThreadPool() { std::cout << "Ask threads to quit\n"; m_WorkToDo_mutex.lock(); for(int i=0; i<m_numOfThreads; ++i) { m_ThreadData[i].haveWorkToDo = true; m_ThreadData[i].typeOfWork = e_quit; } m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); // As each thread terminates, catch them here for(int i=0; i<m_numOfThreads; ++i) { tthread::thread *t = m_ThreadList[i]; // Wait for thread to complete t->join(); } m_numOfThreads = 0; } Example of usage: (this calculates pi-squared/6) struct CalculationDataStruct { int inputVal; double outputVal; }; void LongCalculation( void *theSums ) { CalculationDataStruct *sums = (CalculationDataStruct *)theSums; int terms = sums->inputVal; double sum; for(int i=1; i<terms; i++) sum += 1.0/( double(i)*double(i) ); sums->outputVal = sum; } int main(int argc, char** argv) { int numThreads = 10; // Create pool ThreadPool threadPool; threadPool.CreateThreads(numThreads); // Create thread workspace CalculationDataStruct sums[numThreads]; // Set up jobs for(int i=0; i<numThreads; i++) { sums[i].inputVal = 3000*(i+1); threadPool.SubmitJob(LongCalculation, &sums[i]); } // Run the jobs threadPool.StartJobs(); threadPool.WaitForJobsToComplete(); // Print results for(int i=0; i<numThreads; i++) std::cout << "Sum of " << sums[i].inputVal << " terms is " << sums[i].outputVal << std::endl; return 0; } Question: In the ThreadPool::ThreadFunc method, would better performance be obtained if the following if statement if(NumOfThreadsDoingWork == 0) was included? Also, I'd be grateful of criticisms and ways to improve the code. At the same time, I hope the code is of use to others.

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  • Simple Physics Simulation in java not working.

    - by Static Void Main
    Dear experts, I wanted to implement ball physics and as i m newbie, i adapt the code in tutorial http://adam21.web.officelive.com/Documents/JavaPhysicsTutorial.pdf . i try to follow that as i much as i can, but i m not able to apply all physical phenomenon in code, can somebody please tell me, where i m mistaken or i m still doing some silly programming mistake. The balls are moving when i m not calling bounce method and i m unable to avail the bounce method and ball are moving towards left side instead of falling/ending on floor**, Can some body recommend me some better way or similar easy compact way to accomplish this task of applying physics on two ball or more balls with interactivity. here is code ; import java.awt.*; public class AdobeBall { protected int radius = 20; protected Color color; // ... Constants final static int DIAMETER = 40; // ... Instance variables private int m_x; // x and y coordinates upper left private int m_y; private double dx = 3.0; // delta x and y private double dy = 6.0; private double m_velocityX; // Pixels to move each time move() is called. private double m_velocityY; private int m_rightBound; // Maximum permissible x, y values. private int m_bottomBound; public AdobeBall(int x, int y, double velocityX, double velocityY, Color color1) { super(); m_x = x; m_y = y; m_velocityX = velocityX; m_velocityY = velocityY; color = color1; } public double getSpeed() { return Math.sqrt((m_x + m_velocityX - m_x) * (m_x + m_velocityX - m_x) + (m_y + m_velocityY - m_y) * (m_y + m_velocityY - m_y)); } public void setSpeed(double speed) { double currentSpeed = Math.sqrt(dx * dx + dy * dy); dx = dx * speed / currentSpeed; dy = dy * speed / currentSpeed; } public void setDirection(double direction) { m_velocityX = (int) (Math.cos(direction) * getSpeed()); m_velocityY = (int) (Math.sin(direction) * getSpeed()); } public double getDirection() { double h = ((m_x + dx - m_x) * (m_x + dx - m_x)) + ((m_y + dy - m_y) * (m_y + dy - m_y)); double a = (m_x + dx - m_x) / h; return a; } // ======================================================== setBounds public void setBounds(int width, int height) { m_rightBound = width - DIAMETER; m_bottomBound = height - DIAMETER; } // ============================================================== move public void move() { double gravAmount = 0.02; double gravDir = 90; // The direction for the gravity to be in. // ... Move the ball at the give velocity. m_x += m_velocityX; m_y += m_velocityY; // ... Bounce the ball off the walls if necessary. if (m_x < 0) { // If at or beyond left side m_x = 0; // Place against edge and m_velocityX = -m_velocityX; } else if (m_x > m_rightBound) { // If at or beyond right side m_x = m_rightBound; // Place against right edge. m_velocityX = -m_velocityX; } if (m_y < 0) { // if we're at top m_y = 0; m_velocityY = -m_velocityY; } else if (m_y > m_bottomBound) { // if we're at bottom m_y = m_bottomBound; m_velocityY = -m_velocityY; } // double speed = Math.sqrt((m_velocityX * m_velocityX) // + (m_velocityY * m_velocityY)); // ...Friction stuff double fricMax = 0.02; // You can use any number, preferably less than 1 double friction = getSpeed(); if (friction > fricMax) friction = fricMax; if (m_velocityX >= 0) { m_velocityX -= friction; } if (m_velocityX <= 0) { m_velocityX += friction; } if (m_velocityY >= 0) { m_velocityY -= friction; } if (m_velocityY <= 0) { m_velocityY += friction; } // ...Gravity stuff m_velocityX += Math.cos(gravDir) * gravAmount; m_velocityY += Math.sin(gravDir) * gravAmount; } public Color getColor() { return color; } public void setColor(Color newColor) { color = newColor; } // ============================================= getDiameter, getX, getY public int getDiameter() { return DIAMETER; } public double getRadius() { return radius; // radius should be a local variable in Ball. } public int getX() { return m_x; } public int getY() { return m_y; } } using adobeBall: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class AdobeBallImplementation implements Runnable { private static final long serialVersionUID = 1L; private volatile boolean Play; private long mFrameDelay; private JFrame frame; private MyKeyListener pit; /** true means mouse was pressed in ball and still in panel. */ private boolean _canDrag = false; private static final int MAX_BALLS = 50; // max number allowed private int currentNumBalls = 2; // number currently active private AdobeBall[] ball = new AdobeBall[MAX_BALLS]; public AdobeBallImplementation(Color ballColor) { frame = new JFrame("simple gaming loop in java"); frame.setSize(400, 400); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pit = new MyKeyListener(); pit.setPreferredSize(new Dimension(400, 400)); frame.setContentPane(pit); ball[0] = new AdobeBall(34, 150, 7, 2, Color.YELLOW); ball[1] = new AdobeBall(50, 50, 5, 3, Color.BLUE); frame.pack(); frame.setVisible(true); frame.setBackground(Color.white); start(); frame.addMouseListener(pit); frame.addMouseMotionListener(pit); } public void start() { Play = true; Thread t = new Thread(this); t.start(); } public void stop() { Play = false; } public void run() { while (Play == true) { // bounce(ball[0],ball[1]); runball(); pit.repaint(); try { Thread.sleep(mFrameDelay); } catch (InterruptedException ie) { stop(); } } } public void drawworld(Graphics g) { for (int i = 0; i < currentNumBalls; i++) { g.setColor(ball[i].getColor()); g.fillOval(ball[i].getX(), ball[i].getY(), 40, 40); } } public double pointDistance (double x1, double y1, double x2, double y2) { return Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); } public void runball() { while (Play == true) { try { for (int i = 0; i < currentNumBalls; i++) { for (int j = 0; j < currentNumBalls; j++) { if (pointDistance(ball[i].getX(), ball[i].getY(), ball[j].getX(), ball[j].getY()) < ball[i] .getRadius() + ball[j].getRadius() + 2) { // bounce(ball[i],ball[j]); ball[i].setBounds(pit.getWidth(), pit.getHeight()); ball[i].move(); pit.repaint(); } } } try { Thread.sleep(50); } catch (Exception e) { System.exit(0); } } catch (Exception e) { e.printStackTrace(); } } } public static double pointDirection(int x1, int y1, int x2, int y2) { double H = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); // The // hypotenuse double x = x2 - x1; // The opposite double y = y2 - y1; // The adjacent double angle = Math.acos(x / H); angle = angle * 57.2960285258; if (y < 0) { angle = 360 - angle; } return angle; } public static void bounce(AdobeBall b1, AdobeBall b2) { if (b2.getSpeed() == 0 && b1.getSpeed() == 0) { // Both balls are stopped. b1.setDirection(pointDirection(b1.getX(), b1.getY(), b2.getX(), b2 .getY())); b2.setDirection(pointDirection(b2.getX(), b2.getY(), b1.getX(), b1 .getY())); b1.setSpeed(1); b2.setSpeed(1); } else if (b2.getSpeed() == 0 && b1.getSpeed() != 0) { // B1 is moving. B2 is stationary. double angle = pointDirection(b1.getX(), b1.getY(), b2.getX(), b2 .getY()); b2.setSpeed(b1.getSpeed()); b2.setDirection(angle); b1.setDirection(angle - 90); } else if (b1.getSpeed() == 0 && b2.getSpeed() != 0) { // B1 is moving. B2 is stationary. double angle = pointDirection(b2.getX(), b2.getY(), b1.getX(), b1 .getY()); b1.setSpeed(b2.getSpeed()); b1.setDirection(angle); b2.setDirection(angle - 90); } else { // Both balls are moving. AdobeBall tmp = b1; double angle = pointDirection(b2.getX(), b2.getY(), b1.getX(), b1 .getY()); double origangle = b1.getDirection(); b1.setDirection(angle + origangle); angle = pointDirection(tmp.getX(), tmp.getY(), b2.getX(), b2.getY()); origangle = b2.getDirection(); b2.setDirection(angle + origangle); } } public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { new AdobeBallImplementation(Color.red); } }); } } *EDIT:*ok splitting the code using new approach for gravity from this forum: this code also not working the ball is not coming on floor: public void mymove() { m_x += m_velocityX; m_y += m_velocityY; if (m_y + m_bottomBound > 400) { m_velocityY *= -0.981; // setY(400 - m_bottomBound); m_y = 400 - m_bottomBound; } // ... Bounce the ball off the walls if necessary. if (m_x < 0) { // If at or beyond left side m_x = 0; // Place against edge and m_velocityX = -m_velocityX; } else if (m_x > m_rightBound) { // If at or beyond right side m_x = m_rightBound - 20; // Place against right edge. m_velocityX = -m_velocityX; } if (m_y < 0) { // if we're at top m_y = 1; m_velocityY = -m_velocityY; } else if (m_y > m_bottomBound) { // if we're at bottom m_y = m_bottomBound - 20; m_velocityY = -m_velocityY; } } thanks a lot for any correction and help. jibby

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  • Silverlight 4 WCF RIA Services and MVVM is not as simple

    - by Thomas Jaskula
    [Disclaimer: I'm ASP.NET MVC Developer] Hi, I'm looking for some best practices with implementing MVVM pattern with WCF RIA in Silverlight 4. I'm not looking to use MEF of IoC for locating my ViewModels. What I would like to know is how to apply MVVM pattern with Silverlight 4 and WCF RIA. I don't want to use other stuff like Prism or MVVM Light toolkit. I found many examples on Internet showing how it is wonderful to drag and drop a datasource on the view and the job is done (it reminds me about my first VB6 developments). I tried to implement MVVM with WCF RIA and it's not strightforward at all. If I understand, the MVVM should contain all the logic in order to unit test it in isolation but when it comes to combine it with WCF RIA it's another story. I have the following questions. Can I use a generated metadata as model ? It would be easier to use it that if I write all from the scratch. As I saw the only way I could get data is through DomainContext or through direct binding in the view (local ressource). I don't want the direct binding in the view, not testable at all. On the other hand I can't use DomainContext, it doesn't expose any single entity !!! All I have is the EntitySet that I can bind to datagrid. How do I bind a single Entity to the DataForm from the ViewModel ? How do I udpate the model to the database ? How do I navigate from one Entity to a collection of it's itemps. For example if I have a Company Entity I would like to show a DataFrom to update a entite informations and a datagrid to show companies adresses. When saving a form would like to save information to Company and for example an information avout which adress was selected as active. Please help me understand how to do it well. Or maybe I should drop the WCF RIA and to do it with WCF from scratch ? What do you think ?

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  • WPF - simple relative path - FindAncestor

    - by user309392
    In the XAML below the ToolTip correctly binds to RelativeSource Self. However, I can't for the life of me work out how to get the TextBlock in the commented block to refer to SelectedItem.Description <Controls:RadComboBoxWithCommand x:Name="cmbPacking" Grid.Row="2" Grid.Column="5" ItemsSource="{Binding PackingComboSource}" DisplayMemberPath="DisplayMember" SelectedValuePath="SelectedValue" SelectedValue="{Binding ElementName=dataGrid1, Path=SelectedItem.PackingID}" ToolTip="{Binding RelativeSource={RelativeSource Self}, Path=SelectedItem.Description}" IsSynchronizedWithCurrentItem="True" Style="{StaticResource comboBox}"> <!-- <Controls:RadComboBoxWithCommand.ToolTip>--> <!-- <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, Path=SelectedItem.Description}" TextWrapping="Wrap" Width="50"/>--> <!-- </Controls:RadComboBoxWithCommand.ToolTip>--> </Controls:RadComboBoxWithCommand> I would appreciate any suggestions Thanks - Jeremy

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  • How to generate simple Packing List with MySQL ?

    - by Stephen
    Hi, I need help on how to create a packing list of a shipment with MySQL. Let's say i have 32 boxes of keyboard ready to ship, the master carton can contain 12 boxes. I only have value 32 boxes and volume of 12. The other value in result below is generated by sql command. Not coming from record. So this easily calculate that the number of master carton would be 3 master cartons, with one as a non-standard quantity. How to perform query on this ? As i would like to be this result: +----------+---------------+-------------------+--------+------------+---------+ | Quantity | Standard_Qty | Non_Standard_Qty | Box_N | Box_Total | RowType | +----------+---------------+-------------------+--------+------------+---------+ | 12 | 1 | 0 | 1 | 3 | Detail | | 12 | 1 | 0 | 2 | 3 | Detail | | 8 | 0 | 1 | 3 | 3 | Detail | | 32 | 2 | 1 | | | Summary | +----------+---------------+-------------------+--------+------------+---------+ It looks like two query i know and probably the use of FLOOR command, in which i was teach in here. How to make this result? Thanks in advance. Stephen

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