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  • Question on Virtual Methods

    - by bobber205
    IF both methods are declared as virtual, shouldn't both instances of Method1() that are called be the derived class's Method1()? I am seeing BASE then DERIVED called each time. I am doing some review for an interview and I want to make sure I have this straight. xD class BaseClass { public: virtual void Method1() { cout << "Method 1 BASE" << endl; } }; class DerClass: public BaseClass { public: virtual void Method1() { cout << "Method 1 DERVIED" << endl; } }; DerClass myClass; ((BaseClass)myClass).Method1(); myClass.Method1(); Method 1 BASE Method 1 DERVIED

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  • Python client / server question

    - by AustinM
    I'm working on a bit of a project in python. I have a client and a server. The server listens for connections and once a connection is received it waits for input from the client. The idea is that the client can connect to the server and execute system commands such as ls and cat. This is my server code: import sys, os, socket host = '' port = 50105 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.bind((host, port)) print("Server started on port: ", port) s.listen(5) print("Server listening\n") conn, addr = s.accept() print 'New connection from ', addr while (1): rc = conn.recv(5) pipe = os.popen(rc) rl = pipe.readlines() file = conn.makefile('w', 0) file.writelines(rl[:-1]) file.close() conn.close() And this is my client code: import sys, socket s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) host = 'localhost' port = input('Port: ') s.connect((host, port)) cmd = raw_input('$ ') s.send(cmd) file = s.makefile('r', 0) sys.stdout.writelines(file.readlines()) When I start the server I get the right output, saying the server is listening. But when I connect with my client and type a command the server exits with this error: Traceback (most recent call last): File "server.py", line 21, in <module> rc = conn.recv(2) File "/usr/lib/python2.6/socket.py", line 165, in _dummy raise error(EBADF, 'Bad file descriptor') socket.error: [Errno 9] Bad file descriptor On the client side, I get the output of ls but the server gets screwed up.

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  • jquery - DOM traversal question

    - by David
    Hi, Basically what I have here is a button that adds a new list item to an unordered list. Within this list item is a dropdown box (.formSelector) that when changed triggers an ajax call to get the values for another dropdown box (.fieldSelector) in the same list item. The problem is on this line: $(this).closest(".fieldSelector").append( If I change it to $(".fieldSelector").append( the second box updates correctly. The problem with this is that when I have multiple list items it updates every dropdown box on the page with the class fieldSelector, which is undesirable. How can I traverse the DOM to just pick the fieldSelector in the current list item? Any help is greatly appreciated. Complete code: $("button", "#newReportElement").click(function() { $("#reportElements").append("<li class=\"ui-state-default\"> <span class=\"test ui-icon ui-icon-arrowthick-2-n-s \"></span><span class=\"ui-icon ui-icon-trash deleteRange \"></span> <select name=\"form[]\" class=\"formSelector\"><? foreach ($forms->result() as $row) { echo "<option value='$row->formId'>$row->name</option>"; }?></select><select class=\"fieldSelector\" name=\"field[]\"></select></li>"); $(".deleteRange").button(); $('.formSelector').change(function() { var id = $(this).val(); var url = "<? echo site_url("report/formfields");?>" + "/" + id; var atext = "ids:"; $.getJSON(url, function(data){ $.each(data.items, function(i,item){ $(this).closest(".fieldSelector").append( $('<option></option>').val(item.formId).html(item.formLabel) ); }); }); }); return false; });

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  • managedObjectContext question...

    - by treasure
    Hello, I have an app which is a UITabBarController, I have defined two subviews Both tabs have their Class attribute in the Identity Inspector set to UINavigationController. Now i have managed to get this far with my coding after VERY LONG trials. - (void)viewDidLoad { [super viewDidLoad]; myAppDelegate *appDelegate = (myAppDelegate *)[[UIApplication sharedApplication] delegate]; self.managedObjectContext = appDelegate.managedObjectContext; { NSError *error = nil; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; [fetchRequest setEntity:[NSEntityDescription entityForName:@"User" inManagedObjectContext:self.managedObjectContext]]; NSArray *fetchedItems = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error]; NSEntityDescription *entityDesc = [NSEntityDescription entityForName:@"User" inManagedObjectContext:self.managedObjectContext]; // replace the old data with new. this DOESNT WORK if (fetchedItems.count > 0) { Usr *newUsr; for (newUsr in fetchedItems) { if ([newUsr.name isEqualToString:@"Line One"]) { newUsr.uName = @"Line One (new)"; } } } //add a new default data. THIS ADDS DATA TO MY TABLEVIEW BUT IT DOESNT SAVE THEM TO THE SQLITE User *addedDefaultdata = nil; addedDefaultdata = [[User alloc] initWithEntity:entityDesc insertIntoManagedObjectContext:self.managedObjectContext]; addedDefaultdata.name = @"Added new 1"; [addedDefaultdata release]; } NSError *error = nil; if (![[self fetchedResultsController] performFetch:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } } and my appdelegate looks like this: - (void)applicationDidFinishLaunching:(UIApplication *)application { [application setStatusBarStyle:UIStatusBarStyleBlackOpaque]; [window addSubview:navigationController.view]; [window makeKeyAndVisible]; } now I cannot quire the "User" at all! although i get no errors or warnings! Any suggestions would be much appreciated! Thanks

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  • Another getcwd question...

    - by rubenvb
    Sorry to keep hammering on this, but I'm trying to learn :). Is this any good? And yes, I care about memory leaks. I can't find a decent way of preallocating the char*, because there simply seems to be no cross-platform way. const string getcwd() { char* a_cwd = getcwd(NULL,0); string s_cwd(a_cwd); free(a_cwd); return s_cwd; }

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  • Beginner's Question about accessing mysql using OOP

    - by user345690
    I am reading the PHP and mySQL web development book and so far been doing all the PHP and mysql using procedural. But then it talks about accessing mysql with objects. This works for me: //I define $db so can connect $query="select * FROM testing"; $result=mysqli_query($db,$query); while($row=mysqli_fetch_array($result)){ //echo the data } But when I try to do it with classes, it doesn't $query="select * FROM testing"; $result=$db->query($query); $row=$result->fetch_assoc(); Do I have to write my own class so it defines what query and fetch_assoc does? Or what?

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  • question about prefix and suffix in java

    - by kate
    hi!!I have an issue and i want your help!I have a specific REGEX which i have named it "unique" and i want to store the data that it gives me!! The prefix and the suffix of this regex!!so!!someone has told me to use var prefix and var suffix but i don't know how to do it! for your convinience i give u my xml for this regex <reg name="unique"> <start><![CDATA[ <!-- 72 HOURS FORECASTS --> ]]></start> <end><![CDATA[<!-- 72 HOURS FORECASTS -->]]></end> </reg> the code where i call this regex is int k = 0; for(Xml reg_is:fetchsite.child("site").child("regexps").children("reg")) { if(reg_is.string("name").contains("unique")){ if(reg_is.child("start").content()=="") error += "\tNo prefix reg.exp. given.\n"; else prefix = HtmlMethods.removeBreaks(replaceVariables(reg_is.child("start").content())); if(reg_is.child("end").content()=="") error += "\tNo suffix reg.exp. given.\n"; else suffix = HtmlMethods.removeBreaks(replaceVariables(reg_is.child("end").content())); } else{ poleis[k][0]= HtmlMethods.removeBreaks(reg_is.string("name")); poleis[k][1] = HtmlMethods.removeBreaks(replaceVariables(reg_is.child("start").content())); poleis[k][2] = HtmlMethods.removeBreaks(replaceVariables(reg_is.child("end").content())); k++; }

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  • how to count NULL categories in one SQL question

    - by grzes
    hi, i have a blog application were Post belongsTo Category and Category hasMany Post Post can have a Category or not - in latter case NULL value is present in Post.category_id field. Now i would like to have following category count with single SQL query category|post_count -------------- PHP | 2 JavaScript | 4 SomeOtherCat | 1 NULL | 3 The clue here is that i also want to count posts without category (NULL row above). Is it posibble with one SQL query?

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  • A regular expression question

    - by Hellnar
    Hello, I am in dire need of a such regular expression where my alphabet is made up of 0s and 1s. Now I need a language that accepts all words as long as it has three 0s. IE: 000 10001 0001 1000 10000101

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  • question on src folders in eclipse

    - by Jeff Colapietro
    So, I've been doing android application tutorials and everytime I create a package, for example the helloAndroid tutorial is com.example.android. When it saves this to src it creates a folder for com, another for example and one last one for android. So it gives me the error "class com.example.android does not exist" because its broken into different folders. If anyone can help me out please email me at: [email protected] Thank you very much.

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  • C pointer question, dereferencing crash

    - by skynorth
    Why do this work? int *var; while(scanf("%d", &var) && *var != 0) printf("%d \n", var); While this does not? int *var; while(scanf("%d", &var) && var != 0) printf("%d \n", var); Doesn't * (dereference operator) give you the value pointed by the pointer? So why does *var != 0 crash the program, while var != 0 does not?

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  • iPhone "multi-threading" question

    - by MrDatabase
    I have a simple iPhone game consisting of two "threads": the main game loop where all updating and rendering happen 30 times per second (NSTimer)... and the "thread" that calls the accelerometer delegate 100 times per second. I have a variable "xPosition" that's updated in the accelerometer delegate function and used in the game loop. Is there a possibility of the two "threads" trying to use xPosition at the same time (hence causing a crash or some other problem). If so how can I fix this w/ minimal impact to the game's performance? I've been using this set-up for many months of development and incremental testing and I've never run into any problems. Cheers!

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  • Question about permute-by-sorting

    - by davit-datuashvili
    In the book "Introduction to Algorithms", second edition, there is the following problem: Suppose we have some array: int a[] = {1,2,3,4} and some random priorities array: P = {36,3,97,19} and the goal is to permute the array a randomly using this priorities array. This is the pseudo code: PERMUTE-BY-SORTING (A) 1 n ? length[A] 2 for i ? 1 to n 3 do P[i] = RANDOM (1, n 3) 4 sort A, using P as sort keys 5 return A The result should be the permuted array: B={2, 4, 1, 3}; I have written this code: import java.util.*; public class Permute { public static void main (String[] args) { Random r = new Random(); int a[] = new int[] {1,2,3,4}; int n = a.length; int b[] = new int[a.length]; int p[] = new int[a.length]; for (int i=0; i<p.length; i++) { p[i] = r.nextInt(n*n*n) + 1; } // for (int i=0;i<p.length;i++){ // System.out.println(p[i]); //} } } How do I continue?

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  • Embarassing C++ question regarding const

    - by Neil Butterworth
    My comments on this answer got me thinking about the issues of constness and sorting. I played around a bit and reduced my issues to the fact that this code: #include <vector> int main() { std::vector <const int> v; } will not compile - you can't create a vector of const ints. I suppose I should have known this, but I've never needed to create such a thing before. However, it seems like a useful construct to me, and I wonder if there is any way round this problem - I want to add things to a vector (or whatever), but they should not be changed once added. There's probably some embarrassingly simple solution to this, but it's something I'd never considered before.

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  • indexing question

    - by user522962
    I have a table w/ 3 columns: name, phone, date. I have 3 indexes: 1 on phone, 1 on date and 1 on phone and date. I have the following statement: SELECT * FROM ( SELECT * FROM people WHERE phone IS NOT NULL ORDER BY date DESC) as t GROUP BY phone Basically, I want to get all unique phone numbers ordered by date. This table has about 2.5 million rows but takes forever to execute....are my indexes right? UPDATE: My EXPLAIN statement comes back with 2 rows: 1 for primary table and 1 for derived table. It says I am using temporary and using filesort for my primary table. For my derived table, it says my possible keys are (phone), and (phone, date) but it is using filesort.

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  • Magento - Code Question

    - by user349550
    I will have publications (news papers), under these publications there will be editions [location and language] and under these there will be offers and offers will have products. currently i have created all as modules i.e. publication to add / edit /delete publication, edition to add / edit/ update editions and so on. the problem is how can i get list of all publication when I am creating a edition and same way how can i get list of edition and publication when i am creating a offer. please help/ regards, saurabh

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  • A question about making a C# class persistant during a file load

    - by Adam
    Apologies for the indescriptive title, however it's the best I could think of for the moment. Basically, I've written a singleton class that loads files into a database. These files are typically large, and take hours to process. What I am looking for is to make a method where I can have this class running, and be able to call methods from within it, even if it's calling class is shut down. The singleton class is simple. It starts a thread that loads the file into the database, while having methods to report on the current status. In a nutshell it's al little like this: public sealed class BulkFileLoader { static BulkFileLoader instance = null; int currentCount = 0; BulkFileLoader() public static BulkFileLoader Instance { // Instanciate the instance class if necessary, and return it } public void Go() { // kick of 'ProcessFile' thread } public void GetCurrentCount() { return currentCount; } private void ProcessFile() { while (more rows in the import file) { // insert the row into the database currentCount++; } } } The idea is that you can get an instance of BulkFileLoader to execute, which will process a file to load, while at any time you can get realtime updates on the number of rows its done so far using the GetCurrentCount() method. This works fine, except the calling class needs to stay open the whole time for the processing to continue. As soon as I stop the calling class, the BulkFileLoader instance is removed, and it stops processing the file. What I am after is a solution where it will continue to run independently, regardless of what happens to the calling class. I then tried another approach. I created a simple console application that kicks off the BulkFileLoader, and then wrapped it around as a process. This fixes one problem, since now when I kick off the process, the file will continue to load even if I close the class that called the process. However, now the problem I have is that cannot get updates on the current count, since if I try and get the instance of BulkFileLoader (which, as mentioned before is a singleton), it creates a new instance, rather than returning the instance that is currently in the executing process. It would appear that singletons don't extend into the scope of other processes running on the machine. In the end, I want to be able to kick off the BulkFileLoader, and at any time be able to find out how many rows it's processed. However, that is even if I close the application I used to start it. Can anyone see a solution to my problem?

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  • Easy Regex question

    - by Aaron
    Trying to replace the first 12 digits of credit card numbers with X's in a predictable blob of text that contains the string: Credit Card Number: 1234123412341234 Here's my PHP function: preg_replace('/Credit Card Number: ([0-9]{12})/','Credit Card Number: XXXXXXXXXXXX',$str); Help?

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  • Simple PHP query question: LIKE

    - by pg
    When I replace $ordering = "apples, bananas, cranberries, grapes"; with $ordering = "apples, bananas, grapes"; I no longer want cranberries to be returned by my query, which I've written out like this: $query = "SELECT * from dbname where FruitName LIKE '$ordering'"; Of Course this doesn't work, because I used LIKE wrong. I've read through various manuals that describe how to use LIKE and it doesn't quite make sense to me. If I change the end of the db to "LIKE "apples"" that works for limiting it to just apples. Do I have to explode the ordering on the ", " or is there a way to do this in the query?

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  • C++ beginner question regarding chars

    - by Samwhoo
    I'm just messing around with some C++ at the moment trying to make a simple tic-tac-toe game and I'm running into a bit of a problem. This is my code: #include <iostream> using namespace std; class Square { public: char getState() const; void setState(char); Square(); ~Square(); private: char * pState; }; class Board { public: Board(); ~Board(); void printBoard() const; Square getSquare(short x, short y) const; private: Square board[3][3]; }; int main() { Board board; board.getSquare(1,2).setState('1'); board.printBoard(); return 0; } Square::Square() { pState = new char; *pState = ' '; } Square::~Square() { delete pState; } char Square::getState() const { return *pState; } void Square::setState(char set) { *pState = set; } Board::~Board() { } Board::Board() { } void Board::printBoard() const { for (int x = 0; x < 3; x++) { cout << "|"; for (int y = 0; y < 3; y++) { cout << board[x][y].getState(); } cout << "|" << endl; } } Square Board::getSquare(short x, short y) const { return board[x][y]; } Forgive me if there are blatantly obvious problems with it or it's stupidly written, this is my first program in C++ :p However, the problem is that when I try and set the square 1,2 to the char '1', it doesn't print out as a 1, it prints out as some strange character I didn't recognise. Can anyone tell me why? :) Thanks in advance.

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  • jquery asp.net combo box question

    - by coson
    Good Day, I have a small form with a combo box (ASP.NET Drop Down List control) and a text box (with a DIV id txtName). When the selected index of the combo box changes, I want to clear out the text box. I understand that: $("#txtName").val(''); clears the text box value The thing is the combo box. It contains a list of integers representing the months of the year. The drop down control is called ddlMonths. $("#ddlMonths").change(function() { $("#txtName").val(''); }); I thought by using change, an onSelectedIndexChange event handler would be associated with this control. I also tried (because I've ran into the client id being mangled in ASP.NET w/ jQuery) this: $("#<%=ddlMonths.ClientID%>").change(function() { $("#<%=txtName.ClientID%>").val(''); }); and neither approach seems to be working. Am I missing something? TIA, coson

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  • plain old system.out question

    - by mac
    I was looking at someone's code and saw that he repeatedly declared PrintStream out = System.out; and later called out.println("blah"); I actually thought this was kind of neat. Is this a common practice? Was he just being fancy?

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  • Question about a C macro expansion

    - by holydiver
    I generally have ignored using macros while writing in C but I think I know fundamentals about them. While i was reading the source code of list in linux kernel, i saw something like that: #define LIST_HEAD_INIT(name) { &(name), &(name) } #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) (You can access the remaining part of the code from here.) I didn't understand the function of ampersands(I don't think they are the address of operands here) in LIST_HEAD_INIT and so the use of LIST_HEAD_INIT in the code. I'd appreciate if someone can enlighten me.

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