heap corruption detected after normal block

[MrLibya]

Hello
I've got very wierd bug here , I've made a dialog in my main window ( not the first one ) , anyway the dialog work very well , and when i close the dialog nothing happen it's all ok , but when i close the main dialog after closeing the new dialog i got :

I've check my code and it's all ok ( even all of the feature work fine ) , but I've try something very wierd and it's work , in the dialog.h I've change the place of a varable and it's work as u can see here :

[A Former User]

Hi! Please show us you clientsdialog header and source file.

[MrLibya]

@Wieland here u go : download

if u download it plz tell me :)

Edit: Link removed -- @Wieland

[A Former User]

The website you linked to tries to install plugins to my browser. I don't like malware, please just copy and paste the code here.

[MrLibya]

@Wieland sry about it , i didn't know that ,, anyway here :

source:

#include "clientsdialog.h"
#include "ui_clientsdialog.h"
#include <QDebug>
#include <QSqlError>
#include "mymsg.h"

ClientsDialog::ClientsDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::ClientsDialog)
{
    ui->setupUi(this);
    QObject::connect(ui->name, SIGNAL(returnPressed()), this, SLOT(GetClientInfo()));
    List = new QStringList;
    HeadsTableView = new QStringList;
    client_query = new QSqlQuery;
    CartItems = new QSqlQueryModel(this);
    *HeadsTableView << "رقم الفاتورة" << "اسم المنتج" << "الباركود" << "السعر" << "الكميه" << " التخفيض" << "النوع" << "الاجمالي" << "رقم فاتورة المنتج" << "البائع" << "التاريخ" << "رقم العميل" << "تم اعاد ة المنتج" << "مدفوع";
    client_query->exec("SELECT * FROM [main].[clients]");
    while (client_query->next())
        *List << client_query->value(1).toString();

    search = new QCompleter(*List,this);
    search->setCaseSensitivity(Qt::CaseInsensitive);
    ui->name->setCompleter(search);
}

ClientsDialog::~ClientsDialog()
{
    delete ui;
}

void ClientsDialog::GetClientInfo()
{
    client_query->first();
    if(List->contains(ui->name->text()))
    {
        do
        {
            if(client_query->value(1).toString() == ui->name->text())
            {
                ui->amount->setText(QString::number(client_query->value(2).toDouble()));
                clientid = client_query->value(0).toUInt();
                break;
            }

        }while(client_query->next());
        client_query->exec(QString("SELECT cart_id FROM [main].[sell_later_log] WHERE client_id = '%1' AND refund = 'NO' AND paid = 'NO'").arg(clientid));
        while(client_query->next())
        {
            if(ui->cart_id->findText(client_query->value(0).toString()) == -1)
                ui->cart_id->addItem(client_query->value(0).toString());
        }
        ui->cart_id->setEnabled(true);
        ui->pushButton->setEnabled(true);
    }
}

void ClientsDialog::on_cart_id_currentIndexChanged(const QString &arg1)
{
    double total =0;
    CartItems->setQuery(QString("SELECT * from main.sell_later_log WHERE cart_id = '%1' AND client_id = '%2' AND refund = 'NO' AND paid = 'NO'")
                        .arg(arg1.toUInt()).arg(clientid));
    for(int i=0;i<HeadsTableView->count();i++)
        CartItems->setHeaderData(i, Qt::Horizontal, HeadsTableView->at(i));
    ui->Cart->setModel(CartItems);
    ui->Cart->setColumnHidden(0,true);
    ui->Cart->setColumnHidden(8,true);
    ui->Cart->setColumnHidden(11,true);
    ui->Cart->setColumnHidden(12,true);
    ui->Cart->setColumnHidden(13,true);
    for(int i=0;i<CartItems->rowCount();i++)
        total += CartItems->data(CartItems->index(i,7)).toDouble();
    ui->total->setText(QString::number(total));
}

void ClientsDialog::on_pushButton_clicked()
{
    QSqlDatabase::database().transaction();
    QSqlQuery query;
    for(int i=0;i<HeadsTableView->count();i++)
        query.exec(QString("UPDATE main.sell_later_log SET paid = 'YES' WHERE cart_id ='%1' AND barcode = '%2' AND amount = '%3' AND disscount = '%4' AND type = '%5' AND bill_number = '%6' ")
                   .arg(CartItems->data(CartItems->index(i,0)).toUInt()).arg(CartItems->data(CartItems->index(i,2)).toUInt()).arg(CartItems->data(CartItems->index(i,4)).toUInt()).arg(CartItems->data(CartItems->index(i,5)).toDouble())
                   .arg(CartItems->data(CartItems->index(i,6)).toString()).arg(CartItems->data(CartItems->index(i,8)).toUInt()));
    query.exec(QString("UPDATE main.clients SET cash = cash - '%1' WHERE name = '%2'").arg(ui->total->text().toDouble()).arg(ui->name->text()));
    QSqlDatabase::database().commit();
    ClientFinishPaymentMsg();
    ClientsDialog::close();
}

header:

#ifndef CLIENTSDIALOG_H
#define CLIENTSDIALOG_H

#include <QDialog>
#include <QSqlQuery>
#include <QCompleter>
#include <QSqlQueryModel>

namespace Ui {
class ClientsDialog;
}

class ClientsDialog : public QDialog
{
    Q_OBJECT

public:
    explicit ClientsDialog(QWidget *parent = 0);
    ~ClientsDialog();
private slots:
    void GetClientInfo();
    void on_cart_id_currentIndexChanged(const QString &arg1);

    void on_pushButton_clicked();

private:
    Ui::ClientsDialog *ui;
    QStringList *List;
    QStringList *HeadsTableView;
    QSqlQuery *client_query;
    QSqlQueryModel *CartItems;
    QCompleter *search;
    unsigned int clientid;
};

#endif // CLIENTSDIALOG_H

[jsulm]

@MrLibya Is there a reason why you use pointers and allocate memory on the heap? In the destructor you do not free the memory you allocated in the constructor.

QStringList *List;
QStringList *HeadsTableView;
QSqlQuery *client_query;
QSqlQueryModel *CartItems;
QCompleter *search;

Why not just use normal variables?

QStringList List;
QStringList HeadsTableView;
QSqlQuery client_query;
QSqlQueryModel CartItems;
QCompleter search;

[jsulm]

@MrLibya Just a note: you should stick to one naming convention. Currently you're mixing several different conventions:

• HeadsTableView - camel case with first upper letter
• client_query - underscore as delimiter
  Together with all this unnecessary pointer mess (sorry for being so harsh :-)) it looks really ugly.

I would recommend to not to name variables/methods like HeadsTableView - the first letter should be lower case, else it looks like class name. headsTableView is better.

[MrLibya]

@jsulm I've missunderstand the pointer in Qt , cuz I've seen that Qt is auto destroy the pointers ,
now i've got a look on this link
and now I"m understand it very will , i will fix it thx :)

[jsulm]

@MrLibya Qt only destroys objects which have a parent derived from QObject. Most of the objects you create do not have a parent.
And again: why do you use pointers? In your case there is no need for pointers and heap allocation via new at all.