Creating and laying out widgets using a for loop in Qt - c++

Question

So i wanted to create 5 buttons in Qt but instead, create just one button and put it in a for loop so i don't have to create each of the 5 buttons manually. I tried different ways but all proved futile. I'm new to C++ and Qt.
Here are the codes;
show.h
#ifndef SHOW_H
#define SHOW_H
#include <QDialog>
#include <QPushButton>
#include <QVBoxLayout>
class Show : public QDialog {
Q_OBJECT
public:
explicit Show(QWidget *parent = 0);
~Show();
private:
QPushButton *button;
};
#endif // SHOW_H
show.cpp
#include "show.h"
#include "ui_show.h"
Show::Show(QWidget *parent) : QDialog(parent) {
int a = 5;
button = new QPushButton[a];
button->setText("Ok");
QVBoxLayout *layout = new QVBoxLayout[a];
for (int i = 0; i < sizeof(button)/4; i++) {
/*here, i wanted to do something like this;
'layout[i].addWidget(button[i]);' but didn't work*/
layout[i].addWidget(button);
}
setLayout(layout);
}
Show::~Show() {
}
main.cpp
#include "show.h"
#include <QApplication>
int main(int argc, char *argv[]) {
QApplication a(argc, argv);
Show *dialog = new Show;
dialog->show();
return a.exec();
}
After i run the code, i only see one button.
Your help is deeply appreciated. Thank you!!

Answer 1

QPushButton* pButton = new QPushButton("Ok");
This creates a single instance of a QPushButton.
You can add the button to a layout with a call to Layout::addWidget, which internally calls addItem.
As the documentation states for addItem: -
Note: The ownership of item is transferred to the layout, and it's the layout's responsibility to delete it
So your current code creates a single button and as it gets added to each successive layout, it is removed from the layout in which it was previously added.
You're creating one button and adding the same button 5 times. If you want 5 buttons in 5 layouts using a loop, then you need 5 separate instances of the button: -
for (int i=0; i<5; ++i)
{
QPushButton* pButton = new QPushButton("Ok");
layout[i].addWidget(pButton);
}

Answer 2

In your show.cpp change the lines
Show::Show(QWidget *parent) : QDialog(parent) {
int a = 5;
// You only need one layout for all buttons, not one per button.
QVBoxLayout *layout = new QVBoxLayout( this );
for (int i = 0; i < a; i++) {
QPushButton * newButton = new QPushButton( this );
newButton ->setText( "Ok" );
layout->addWidget( newButton );
}
setLayout(layout);
}
Show::~Show() {
}
The layout expects a pointer and you only need one layout instead one per button.