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  • Object of an abstract class

    - by webgenius
    Why is it not possible to create an object of an abstract class? I understand that the compiler creates a VTABLE with VPTR pointing to NULL. Does this prevent from creating an object of an abstract class?

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  • C: reading file and populating struct

    - by deostroll
    Hi, I have a structure with the following definition: typedef struct myStruct{ int a; char* c; int f; } OBJECT; I am able to populate this object and write it to a file. However I am not able to read the char* c value in it...while trying to read it, it gives me a segmentation fault error. Is there anything wrong with my code: //writensave.c #include "mystruct.h" #include <stdio.h> #include <string.h> #define p(x) printf(x) int main() { p("Creating file to write...\n"); FILE* file = fopen("struct.dat", "w"); if(file == NULL) { printf("Error opening file\n"); return -1; } p("creating structure\n"); OBJECT* myObj = (OBJECT*)malloc(sizeof(OBJECT)); myObj->a = 20; myObj->f = 45; myObj->c = (char*)calloc(30, sizeof(char)); strcpy(myObj->c, "This is a test"); p("Writing object to file...\n"); fwrite(myObj, sizeof(OBJECT), 1, file); p("Close file\n"); fclose(file); p("End of program\n"); return 0; } Here is how I am trying to read it: //readnprint.c #include "mystruct.h" #include <stdio.h> #define p(x) printf(x) int main() { FILE* file = fopen("struct.dat", "r"); char* buffer; buffer = (char*) malloc(sizeof(OBJECT)); if(file == NULL) { p("Error opening file"); return -1; } fread((void *)buffer, sizeof(OBJECT), 1, file); OBJECT* obj = (OBJECT*)buffer; printf("obj->a = %d\nobj->f = %d \nobj->c = %s", obj->a, obj->f, obj->c); fclose(file); return 0; }

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  • Why One-to-one relationship dosen't work?

    - by eugenn
    I'm trying to create a very simple relationship between two objects. Can anybody explain me why I can't find the Company object via findBy method? class Company { String name String desc City city static constraints = { city(unique: true) } } class City { String name static constraints = { } } class BootStrap { def init = { servletContext -> new City(name: 'Tokyo').save() new City(name: 'New York').save() new Company(name: 'company', city: City.findByName('New York')).save() def c = Company.findByName('company') // Why c=null????! } def destroy = { } }

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  • Show child and parent together using CONNECT BY Sql statement

    - by martilyo
    I have an sql statement that currently is just returning all the end parent rows for a list of child rows: SELECT DISTINCT row FROM table heirarchy WHERE parent_row = NULL CONNECT BY nocycle PRIOR parent_row = row START WITH row IN (select statement returning child rows) Is there a way to show the child and its corresponding parent together in the same result set using a modified version of my sql? Thanks.

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  • get value from jtable

    - by jouzef19
    hi I have a jtable and I want the user to fill its cells then i get what he wrote! the problem is when i try getValueAt(row index,col index ) the programe give me null , and i am sure that the cell i choose has a value .

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  • about Select statement !

    - by user329820
    hi, I have read that after select we use column-names but I have found a statement that was like this: SELECT 'A' FROM T WHERE A = NULL; would you lease help me? thanks (A is a column- name here?) my DBMS is MySQL

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  • How SQLite on Android handles long stings?

    - by Levara
    Hi! I'm wondering how Android's implementation of SQLite handles long Strings. Reading from online documentation on sqlite, it said that strings in sqlite are limited to 1 million characters. My strings are definitely smaller. I'm creating a simple RSS application, and after parsing a html document, and extracting text, I'm having problem saving it to a database. I have 2 tables in database, feeds and articles. RSS feeds are correctly saved and retrieved from feeds table, but when saving to the articles table, logcat is saying that it cannot save extracted text to it's column. I don't know if other columns are making problems too, no mention of them in logcat. I'm wondering, since text is from an article on web, are signs like (",',;) creating problems? Is Android automaticaly escaping them, or I have to do that. I'm using a technique for inserting similar to one in notepad tutorial: public long insertArticle(long feedid, String title, String link, String description, String h1, String h2, String h3, String p, String image, long date) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_FEEDID, feedid); initialValues.put(KEY_TITLE, title); initialValues.put(KEY_LINK, link); initialValues.put(KEY_DESCRIPTION, description ); initialValues.put(KEY_H1, h1 ); initialValues.put(KEY_H2, h2); initialValues.put(KEY_H3, h3); initialValues.put(KEY_P, p); initialValues.put(KEY_IMAGE, image); initialValues.put(KEY_DATE, date); return mDb.insert(DATABASE_TABLE_ARTICLES,null, initialValues); } Column P is for extracted text, h1, h2 and h3 are for headers from a page. Logcat reports only column p to be the problem. The table is created with following statement: private static final String DATABASE_CREATE_ARTICLES = "create table articles( _id integer primary key autoincrement, feedid integer, title text, link text not null, description text," + "h1 text, h2 text, h3 text, p text, image text, date integer);"; Thanks!

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  • Django modelform ForeignKey List

    - by Harry
    How do you get each item in the ForeignKey field in a list, for example: class Delegate(models.Model): excursion = models.ForeignKey(Excursion, limit_choices_to = {'is_activity': False}, related_name='excursion', null=True, blank=True) Template: {% for object in formset.excursion_set.all %} {{ object.lable }} etc {% endfor %} My reason is that I don't want the options to display as a dropdown, but in a custom way that I will style etc.

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  • j2me or android file upload to jsp

    - by user313613
    hi i new to mobile development i like to upload the file from blackberry and android how to develop the mobile side to this jsp page. please do reply me thanks here i mention the jsp file from roseindia.net. <%@ page import="java.io.*" % <% //to get the content type information from JSP Request Header String contentType = request.getContentType(); //here we are checking the content type is not equal to Null and as well as the passed data from mulitpart/form-data is greater than or equal to 0 if ((contentType != null) && (contentType.indexOf("multipart/form-data") = 0)) { DataInputStream in = new DataInputStream(request. getInputStream()); //we are taking the length of Content type data int formDataLength = request.getContentLength(); byte dataBytes[] = new byte[formDataLength]; int byteRead = 0; int totalBytesRead = 0; //this loop converting the uploaded file into byte code while (totalBytesRead < formDataLength) { byteRead = in.read(dataBytes, totalBytesRead, formDataLength); totalBytesRead += byteRead; } String file = new String(dataBytes); //for saving the file name String saveFile = file.substring(file.indexOf("filename=\"") + 10); saveFile = saveFile.substring(0, saveFile.indexOf("\n")); saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\"")); int lastIndex = contentType.lastIndexOf("="); String boundary = contentType.substring(lastIndex + 1, contentType.length()); int pos; //extracting the index of file pos = file.indexOf("filename=\""); pos = file.indexOf("\n", pos) + 1; pos = file.indexOf("\n", pos) + 1; pos = file.indexOf("\n", pos) + 1; int boundaryLocation = file.indexOf(boundary, pos) - 4; int startPos = ((file.substring(0, pos)).getBytes()).length; int endPos = ((file.substring(0, boundaryLocation)) .getBytes()).length; // creating a new file with the same name and writing the content in new file FileOutputStream fileOut = new FileOutputStream(saveFile); fileOut.write(dataBytes, startPos, (endPos - startPos)); fileOut.flush(); fileOut.close(); %><Br><table border="2"><tr><td><b>You have successfully upload the file by the name of: <% out.println(saveFile); % <% } %

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  • hibernate - uniqueResult silently fails

    - by robinmag
    I have a login controller that use the hibernate uniqueResult method. Everything works fine when i test it in eclipse's tomcat server. But when i deploy my webapps to tomcat server (on the same machine) it fails: it always returns null even i use the correct credential. Here is my hibernate code: session.createCriteria(User.class) .add(Restrictions.eq(User.USERNAME_FIELD, userName)) .add(Restrictions.eq(User.PASSWORD_FIELD, password)).uniqueResult(); Thank you!

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  • Obtaining ActiveRecords if NOT nil

    - by user275729
    I would like to be able to gather all records in a table where the user_id is not null. This is what I have but it doesn't seem to be working (even though I've had it working in a seperate project): named_scope :all_registered, :conditions => ["user_id != ?", nil]

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  • How to PlaySound in C++

    - by user189748
    i try to play a music file in my coding, but failed. i have my music file in the same folder which save .cpp file. can someone help me? my code is: #include <iostream> #include <windows.h> int main() { PlaySound("kenny g.WAV", NULL, SND_ASYNC); }

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  • java classcast exception

    - by shil
    hi i have problems in converting an XML document type into a Document object.. this is the piece of code line 1 : Document doc=null; line 2 : doc = (Document) parser.parse(sourceFile); for this line 2 it throws java classcast exception.. without the typecast it shows error as "Type mismatch: cannot convert from org.w3c.dom.Document to javax.swing.text.Document" how do i now typecast properly? any suggestions??

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  • Problem in Union Join For MySQL Query

    - by Mac Taylor
    hey guys i managed to select from a table that saves my latest posts but i need to have double condition in selection here is my code : $sql_query = "SELECT b.*,u.username AS MY_Sender FROM TABLE_users u,TABLE_blogs b Where b.reciever = '0' AND u.user_id = b.sender UNION SELECT b.*,u.username AS MY_reciever FROM TABLE_users u,TABLE_blogs b Where b.reciever != '0' AND u.user_id = b.reciever ORDER BY bid DESC LIMIT 0,7 "; but MY_reciever is Null and empty Am i wrong in using UNION for this need ?!

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  • Get Const / Static Name from Function / Method Call.

    - by Mark Tomlin
    I want to find the token's name passed by augment into a function. class Norm { const STR_NORM = 0; const INT_NORM = 0; } function foo($Arg1, $Arg2 = NULL) { getConstName($Arg1); # Should Return STR_NORM; return $Arg1, $Arg2; } echo foo(Norm::STR_NORM); Is there any way to impalement getConstName via the PHP Reflection API?

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  • Modifying an observable collection bound to a ListBox

    - by Rohit Kandhal
    I've a collection in viewmodel binded to listbox. I want to hide a particular type from the collection. Here is the code: public ObservableCollection [YZModeModelView] YZModeModelView { return this.XModelVIew.YZModelViewCollection; } I want to a particular type of model view's from YZModelViewCollection. eg. ModelView's with property abc set to null. Any suggestions ...

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  • Linked list Recursion ...

    - by epsilon_G
    hey , I'd like to make a recursive function using C++ I make this class class linklist { private: struct node { int data; node *link; }*p; void linklist::print_num(node* p) { if (p != NULL) { cout << p->data << " "; print_num (p->link); } } in the main program what should I write ...

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  • Dynamic populate ComboBox (Flex)

    - by Vinzcent
    Hey, I want to populate a ComboBox after a clicked a button. This is my code: var dpNames:ArrayCollection = new ArrayCollection(); for each(var ca:Categorie in arrCategories) { dpNames.addItem ({label: ca.name, data: ca.value}); } cbWijzigCategorie.dataProvider = dpNames; But when he executes the last line, I alwas get the following error: TypeError: Error #1009: Cannot access a property or method of a null object reference. I have no idea why. Thanks a lot, Vincent

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  • Conditional Update stored proc is firing a trigger always

    - by schar
    I have a stored procedure that says update table1 set value1 = 1 where value1 = 0 and date < getdate() I have a trigger that goes like CREATE TRIGGER NAME ON TABLENAME FOR UPDATE ... if UPDATE(value1) BEGIN --Some code to figure out that this trigger has been called -- the value is always null END Any idea why this trigger is called even when the stored procedure does not update any values?

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  • url routing with strongly typed objects

    - by user510336
    hello all , I am trying to create url routing with strongly typed objects for pages but I keep getting null object on the first line so it's crashing //Getting the suitable executing Page var display = BuildManager.CreateInstanceFromVirtualPath(_virtualPath,typeof(Page)) as IProfileHandler; //Setting Page Parameters display.MemberId = Convert.ToInt32(requestContext.RouteData.Values["ID"]); //Return Page return display; public interface IProfileHandler : IHttpHandler { int MemberId { get; set; } }

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  • Multi-threaded random_r is slower than single threaded version.

    - by Nixuz
    The following program is essentially the same the one described here. When I run and compile the program using two threads (NTHREADS == 2), I get the following run times: real 0m14.120s user 0m25.570s sys 0m0.050s When it is run with just one thread (NTHREADS == 1), I get run times significantly better even though it is only using one core. real 0m4.705s user 0m4.660s sys 0m0.010s My system is dual core, and I know random_r is thread safe and I am pretty sure it is non-blocking. When the same program is run without random_r and a calculation of cosines and sines is used as a replacement, the dual-threaded version runs in about 1/2 the time as expected. #include <pthread.h> #include <stdlib.h> #include <stdio.h> #define NTHREADS 2 #define PRNG_BUFSZ 8 #define ITERATIONS 1000000000 void* thread_run(void* arg) { int r1, i, totalIterations = ITERATIONS / NTHREADS; for (i = 0; i < totalIterations; i++){ random_r((struct random_data*)arg, &r1); } printf("%i\n", r1); } int main(int argc, char** argv) { struct random_data* rand_states = (struct random_data*)calloc(NTHREADS, sizeof(struct random_data)); char* rand_statebufs = (char*)calloc(NTHREADS, PRNG_BUFSZ); pthread_t* thread_ids; int t = 0; thread_ids = (pthread_t*)calloc(NTHREADS, sizeof(pthread_t)); /* create threads */ for (t = 0; t < NTHREADS; t++) { initstate_r(random(), &rand_statebufs[t], PRNG_BUFSZ, &rand_states[t]); pthread_create(&thread_ids[t], NULL, &thread_run, &rand_states[t]); } for (t = 0; t < NTHREADS; t++) { pthread_join(thread_ids[t], NULL); } free(thread_ids); free(rand_states); free(rand_statebufs); } I am confused why when generating random numbers the two threaded version performs much worse than the single threaded version, considering random_r is meant to be used in multi-threaded applications.

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  • How can I create an empty dummy HttpResponse

    - by jax
    I am using org.apache.http.HttpResponse I want to create an empty dummy resposne, I am going to use this to return when errors occur instead of passing back null. I tried to create one and it has lost of weird params. Can someone tell me how to create one.

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