New Dialog Problem

Why is this happening?
Attachment 12902

//mainwindow.cpp

Code:

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#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QtCore>
#include<QtGui>
#include<QMessageBox>
#include"secondwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_clicked()
{
    QMessageBox::information (this, "Title", "kaydedildi");
}
 
[B]void MainWindow::on_pushButton_3_clicked()  //When i clicked this button the problem occurs
{
    msecond = new Secondwindow(this);
    msecond->show();
}[/B]

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I found the solution.
for those one who are wondering

Code:

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void MainWindow::on_pushButton_3_clicked()  
{
    msecond = new Secondwindow(this);      //it should be like  msecond = new Secondwindow();
    msecond->show();

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Your code has a memory leak. Each time the button_clicked slot is executed, you create a -new- Secondwindow instance. Unless you delete this later, it creates a memory leak.

The usual model for creating and displaying dialogs is to create them on the stack, use a call to exec() to show them as modal dialogs, respond to the return value from the dialog, and exit the slot:

Code:

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void MainWindow::on_pushButton_3_clicked()  
{
     Secondwindow msecond(this);      
     if ( QDialog::Accepted == msecond.exec() )
     {
        // do something with the result
     }
}  // slot exits, second window gets destroyed automatically

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