QtWidgets documentation: cleanup

Cleanup the QtWidgets documentation:
 - use new signal/slot syntax
 - use range-based for loop instead foreach

Change-Id: I621b1ddac108d3df676209241d93d9b4f04a25fe
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

19 files changed, 102 insertions, 111 deletions

diff --git a/src/widgets/doc/snippets/code/src_gui_itemviews_qdatawidgetmapper.cpp b/src/widgets/doc/snippets/code/src_gui_itemviews_qdatawidgetmapper.cpp
index 4dad563660..cc1568cb9d 100644
--- a/src/widgets/doc/snippets/code/src_gui_itemviews_qdatawidgetmapper.cpp
+++ b/src/widgets/doc/snippets/code/src_gui_itemviews_qdatawidgetmapper.cpp
@@ -59,7 +59,7 @@ mapper->toFirst();
 
 
 //! [1]
-QDataWidgetMapper *mapper = new QDataWidgetMapper();
+QDataWidgetMapper *mapper = new QDataWidgetMapper;
 mapper->setModel(myModel);
 mapper->addMapping(nameLineEdit, 0);
 mapper->addMapping(ageSpinBox, 1);
@@ -67,7 +67,7 @@ mapper->addMapping(ageSpinBox, 1);
 
 
 //! [2]
-QDataWidgetMapper *mapper = new QDataWidgetMapper();
-connect(myTableView->selectionModel(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)),
-        mapper, SLOT(setCurrentModelIndex(QModelIndex)));
+QDataWidgetMapper *mapper = new QDataWidgetMapper;
+connect(myTableView->selectionModel(), &QItemSelectionModel::currentRowChanged,
+        mapper, &QDataWidgetMapper::setCurrentModelIndex);
 //! [2]
diff --git a/src/widgets/doc/snippets/code/src_gui_kernel_qapplication.cpp b/src/widgets/doc/snippets/code/src_gui_kernel_qapplication.cpp
index a907a0421f..0a70c1d32a 100644
--- a/src/widgets/doc/snippets/code/src_gui_kernel_qapplication.cpp
+++ b/src/widgets/doc/snippets/code/src_gui_kernel_qapplication.cpp
@@ -100,7 +100,8 @@ QSize MyWidget::sizeHint() const
 //! [4]
 void showAllHiddenTopLevelWidgets()
 {
-    foreach (QWidget *widget, QApplication::topLevelWidgets()) {
+    const QWidgetList topLevelWidgets = QApplication::topLevelWidgets();
+    for (QWidget *widget : topLevelWidgets) {
         if (widget->isHidden())
             widget->show();
     }
@@ -111,7 +112,8 @@ void showAllHiddenTopLevelWidgets()
 //! [5]
 void updateAllWidgets()
 {
-    foreach (QWidget *widget, QApplication::allWidgets())
+    const QWidgetList allWidgets = QApplication::allWidgets();
+    for (QWidget *widget : allWidgets)
         widget->update();
 }
 //! [5]
@@ -171,13 +173,15 @@ appname -session id
 
 
 //! [10]
-foreach (const QString &command, mySession.restartCommand())
+const QStringList commands = mySession.restartCommand();
+for (const QString &command : commands)
     do_something(command);
 //! [10]
 
 
 //! [11]
-foreach (const QString &command, mySession.discardCommand())
+const QStringList commands = mySession.discardCommand();
+for (const QString &command : commands)
     do_something(command);
 //! [11]
 
diff --git a/src/widgets/doc/snippets/code/src_gui_widgets_qmenu.cpp b/src/widgets/doc/snippets/code/src_gui_widgets_qmenu.cpp
index 4b1c4cd645..da3fd28056 100644
--- a/src/widgets/doc/snippets/code/src_gui_widgets_qmenu.cpp
+++ b/src/widgets/doc/snippets/code/src_gui_widgets_qmenu.cpp
@@ -81,7 +81,7 @@ exec(e->globalPos());
 //! [6]
 QMenu menu;
 QAction *at = actions[0]; // Assumes actions is not empty
-foreach (QAction *a, actions)
+for (QAction *a : qAsConst(actions))
     menu.addAction(a);
 menu.exec(pos, at);
 //! [6]
diff --git a/src/widgets/doc/snippets/dialogs/dialogs.cpp b/src/widgets/doc/snippets/dialogs/dialogs.cpp
index cca3ac8d75..7fa793c70f 100644
--- a/src/widgets/doc/snippets/dialogs/dialogs.cpp
+++ b/src/widgets/doc/snippets/dialogs/dialogs.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 typedef QDialog WordCountDialog;
 typedef QDialog FindDialog;
@@ -76,7 +76,8 @@ void EditorWindow::find()
 {
     if (!findDialog) {
         findDialog = new FindDialog(this);
-        connect(findDialog, SIGNAL(findNext()), this, SLOT(findNext()));
+        connect(findDialog, &FindDialog::findNext,
+                this, &EditorWindow::findNext);
     }
 
     findDialog->show();
@@ -249,9 +250,9 @@ Operation::Operation(QObject *parent)
     : QObject(parent), steps(0)
 {
     pd = new QProgressDialog("Operation in progress.", "Cancel", 0, 100);
-    connect(pd, SIGNAL(canceled()), this, SLOT(cancel()));
+    connect(pd, &QProgressDialog::canceled, this, &Operation::cancel);
     t = new QTimer(this);
-    connect(t, SIGNAL(timeout()), this, SLOT(perform()));
+    connect(t, &QTimer::timeout, this, &Operation::perform);
     t->start(0);
 }
 //! [4] //! [5]
diff --git a/src/widgets/doc/snippets/dockwidgets/mainwindow.cpp b/src/widgets/doc/snippets/dockwidgets/mainwindow.cpp
index f6959cc12b..53f91589bf 100644
--- a/src/widgets/doc/snippets/dockwidgets/mainwindow.cpp
+++ b/src/widgets/doc/snippets/dockwidgets/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -63,8 +63,8 @@ MainWindow::MainWindow(QWidget *parent)
 
     textBrowser = new QTextBrowser(this);
 
-    connect(headingList, SIGNAL(itemClicked(QListWidgetItem*)),
-            this, SLOT(updateText(QListWidgetItem*)));
+    connect(headingList, &QListWidget::itemClicked,
+            this, &MainWindow::updateText);
 
     updateText(headingList->item(0));
     headingList->setCurrentRow(0);
@@ -119,7 +119,7 @@ void MainWindow::setupMenus()
     QAction *exitAct = new QAction(tr("E&xit"), this);
     exitAct->setShortcut(tr("Ctrl+Q"));
     exitAct->setStatusTip(tr("Exit the application"));
-    connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));
+    connect(exitAct, &QAction::triggered, qApp, &QApplication::closeAllWindows);
 
     QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
     fileMenu->addAction(exitAct);
diff --git a/src/widgets/doc/snippets/mdiareasnippets.cpp b/src/widgets/doc/snippets/mdiareasnippets.cpp
index b9d6f05daf..dec7aaa1e7 100644
--- a/src/widgets/doc/snippets/mdiareasnippets.cpp
+++ b/src/widgets/doc/snippets/mdiareasnippets.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 void mainWindowExample()
 {
@@ -95,7 +95,7 @@ int main(int argv, char **args)
    QAction *act = new QAction(qApp);
    act->setShortcut(Qt::ALT + Qt::Key_S);
    act->setShortcutContext( Qt::ApplicationShortcut );
-   QObject::connect(act, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+   QObject::connect(act, &QAction::triggered, qApp, &QApplication::aboutQt);
 
     QWidget widget5;
     widget5.show();
diff --git a/src/widgets/doc/snippets/qlistview-dnd/mainwindow.cpp b/src/widgets/doc/snippets/qlistview-dnd/mainwindow.cpp
index c2af9c4cf1..45f1eb7aa3 100644
--- a/src/widgets/doc/snippets/qlistview-dnd/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qlistview-dnd/mainwindow.cpp
@@ -73,7 +73,8 @@ listView->setDropIndicatorShown(true);
 
     this->listView = listView;
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
+    connect(quitAction, &QAction::triggered,
+            this, &QWidget::close);
 
     setupListItems();
 
diff --git a/src/widgets/doc/snippets/qlistview-dnd/model.cpp b/src/widgets/doc/snippets/qlistview-dnd/model.cpp
index 710bbb2964..6835479e7a 100644
--- a/src/widgets/doc/snippets/qlistview-dnd/model.cpp
+++ b/src/widgets/doc/snippets/qlistview-dnd/model.cpp
@@ -54,7 +54,7 @@
   A simple model that uses a QStringList as its data source.
 */
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "model.h"
 
@@ -121,7 +121,7 @@ bool DragDropListModel::dropMimeData(const QMimeData *data,
 
 //! [6]
     insertRows(beginRow, rows, QModelIndex());
-    foreach (const QString &text, newItems) {
+    for (const QString &text : qAsConst(newItems)) {
         QModelIndex idx = index(beginRow, 0, QModelIndex());
         setData(idx, text);
         beginRow++;
@@ -146,12 +146,12 @@ Qt::ItemFlags DragDropListModel::flags(const QModelIndex &index) const
 //! [8]
 QMimeData *DragDropListModel::mimeData(const QModelIndexList &indexes) const
 {
-    QMimeData *mimeData = new QMimeData();
+    QMimeData *mimeData = new QMimeData;
     QByteArray encodedData;
 
     QDataStream stream(&encodedData, QIODevice::WriteOnly);
 
-    foreach (const QModelIndex &index, indexes) {
+    for (const QModelIndex &index : indexes) {
         if (index.isValid()) {
             QString text = data(index, Qt::DisplayRole).toString();
             stream << text;
diff --git a/src/widgets/doc/snippets/qlistwidget-dnd/mainwindow.cpp b/src/widgets/doc/snippets/qlistwidget-dnd/mainwindow.cpp
index 1153250b17..70df2b112e 100644
--- a/src/widgets/doc/snippets/qlistwidget-dnd/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qlistwidget-dnd/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -74,7 +74,7 @@ listWidget->setDragDropMode(QAbstractItemView::InternalMove);
 
     this->listWidget = listWidget;
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
 
     setupListItems();
 
diff --git a/src/widgets/doc/snippets/qlistwidget-using/mainwindow.cpp b/src/widgets/doc/snippets/qlistwidget-using/mainwindow.cpp
index ff69fd2efd..13b20bb856 100644
--- a/src/widgets/doc/snippets/qlistwidget-using/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qlistwidget-using/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -77,14 +77,13 @@ MainWindow::MainWindow()
     listWidget = new QListWidget(this);
     listWidget->setSelectionMode(QAbstractItemView::SingleSelection);
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
-    connect(ascendingAction, SIGNAL(triggered()), this, SLOT(sortAscending()));
-    connect(descendingAction, SIGNAL(triggered()), this, SLOT(sortDescending()));
-    connect(insertAction, SIGNAL(triggered()), this, SLOT(insertItem()));
-    connect(removeAction, SIGNAL(triggered()), this, SLOT(removeItem()));
-    connect(listWidget,
-            SIGNAL(currentItemChanged(QListWidgetItem*,QListWidgetItem*)),
-            this, SLOT(updateMenus(QListWidgetItem*)));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
+    connect(ascendingAction, &QAction::triggered, this, &MainWindow::sortAscending);
+    connect(descendingAction, &QAction::triggered, this, &MainWindow::sortDescending);
+    connect(insertAction, &QAction::triggered, this, &MainWindow::insertItem);
+    connect(removeAction, &QAction::triggered, this, &MainWindow::removeItem);
+    connect(listWidget, &QListWidget::currentItemChanged,
+            this, &MainWindow::updateMenus);
 
     setupListItems();
     updateMenus(listWidget->currentItem());
diff --git a/src/widgets/doc/snippets/qsortfilterproxymodel/main.cpp b/src/widgets/doc/snippets/qsortfilterproxymodel/main.cpp
index a6284bd578..2d4b1023f1 100644
--- a/src/widgets/doc/snippets/qsortfilterproxymodel/main.cpp
+++ b/src/widgets/doc/snippets/qsortfilterproxymodel/main.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 int main(int argc, char *argv[])
 {
@@ -74,9 +74,8 @@ int main(int argc, char *argv[])
     filteredView->setWindowTitle("Filtered view onto a string list model");
 
     QLineEdit *patternEditor = new QLineEdit;
-    QObject::
-    connect(patternEditor, SIGNAL(textChanged(QString)),
-            filterModel, SLOT(setFilterRegExp(QString)));
+    QObject::connect(patternEditor, &QLineEdit::textChanged,
+                     filterModel, &QSortFilterProxyModel::setFilterWildcard);
 
     QVBoxLayout *layout = new QVBoxLayout(window);
     layout->addWidget(filteredView);
diff --git a/src/widgets/doc/snippets/qstackedlayout/main.cpp b/src/widgets/doc/snippets/qstackedlayout/main.cpp
index 765608848c..9c61939dee 100644
--- a/src/widgets/doc/snippets/qstackedlayout/main.cpp
+++ b/src/widgets/doc/snippets/qstackedlayout/main.cpp
@@ -48,13 +48,12 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
-#include <QApplication>
+#include <QtWidgets>
 
 class Widget : public QWidget
 {
 public:
-    Widget(QWidget *parent = 0);
+    Widget(QWidget *parent = nullptr);
 };
 
 Widget::Widget(QWidget *parent)
@@ -75,8 +74,8 @@ Widget::Widget(QWidget *parent)
     pageComboBox->addItem(tr("Page 1"));
     pageComboBox->addItem(tr("Page 2"));
     pageComboBox->addItem(tr("Page 3"));
-    connect(pageComboBox, SIGNAL(activated(int)),
-            stackedLayout, SLOT(setCurrentIndex(int)));
+    connect(pageComboBox, QOverload<int>::of(&QComboBox::activated),
+            stackedLayout, &QStackedLayout::setCurrentIndex);
 //! [1]
 
 //! [2]
diff --git a/src/widgets/doc/snippets/qstackedwidget/main.cpp b/src/widgets/doc/snippets/qstackedwidget/main.cpp
index a6c9c7afe3..077c281830 100644
--- a/src/widgets/doc/snippets/qstackedwidget/main.cpp
+++ b/src/widgets/doc/snippets/qstackedwidget/main.cpp
@@ -48,8 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
-#include <QApplication>
+#include <QtWidgets>
 
 class Widget : public QWidget
 {
@@ -75,8 +74,8 @@ Widget::Widget(QWidget *parent)
     pageComboBox->addItem(tr("Page 1"));
     pageComboBox->addItem(tr("Page 2"));
     pageComboBox->addItem(tr("Page 3"));
-    connect(pageComboBox, SIGNAL(activated(int)),
-            stackedWidget, SLOT(setCurrentIndex(int)));
+    connect(pageComboBox, QOverload<int>::of(&QComboBox::activated),
+            stackedWidget, &QStackedWidget::setCurrentIndex);
 
 //! [1] //! [2]
     QVBoxLayout *layout = new QVBoxLayout;
diff --git a/src/widgets/doc/snippets/qtablewidget-resizing/mainwindow.cpp b/src/widgets/doc/snippets/qtablewidget-resizing/mainwindow.cpp
index 95113153e1..d2c50336f6 100644
--- a/src/widgets/doc/snippets/qtablewidget-resizing/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qtablewidget-resizing/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -72,9 +72,9 @@ MainWindow::MainWindow()
 //! [0]
     tableWidget->setSelectionMode(QAbstractItemView::ExtendedSelection);
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
-    connect(tableWidthAction, SIGNAL(triggered()), this, SLOT(changeWidth()));
-    connect(tableHeightAction, SIGNAL(triggered()), this, SLOT(changeHeight()));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
+    connect(tableWidthAction, &QAction::triggered, this, &MainWindow::changeWidth);
+    connect(tableHeightAction, &QAction::triggered, this, &MainWindow::changeHeight);
 
     setupTableItems();
 
diff --git a/src/widgets/doc/snippets/qtablewidget-using/mainwindow.cpp b/src/widgets/doc/snippets/qtablewidget-using/mainwindow.cpp
index 15b9457dd5..47b63b2b3f 100644
--- a/src/widgets/doc/snippets/qtablewidget-using/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qtablewidget-using/mainwindow.cpp
@@ -48,8 +48,8 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
-#include "math.h"
+#include <QtWidgets>
+#include <math.h>
 
 #include "mainwindow.h"
 
@@ -89,9 +89,9 @@ MainWindow::MainWindow()
     tableWidget->setHorizontalHeaderItem(1, squaresHeaderItem);
     tableWidget->setHorizontalHeaderItem(2, cubesHeaderItem);
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
-    connect(sumItemsAction, SIGNAL(triggered()), this, SLOT(sumItems()));
-    connect(averageItemsAction, SIGNAL(triggered()), this, SLOT(averageItems()));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
+    connect(sumItemsAction, &QAction::triggered, this, &MainWindow::sumItems);
+    connect(averageItemsAction, &QAction::triggered, this, &MainWindow::averageItems);
 
     setupTableItems();
 
@@ -119,12 +119,11 @@ void MainWindow::setupTableItems()
 
 void MainWindow::averageItems()
 {
-    QList<QTableWidgetItem *> selected = tableWidget->selectedItems();
-    QTableWidgetItem *item;
+    const QList<QTableWidgetItem *> selected = tableWidget->selectedItems();
     int number = 0;
     double total = 0;
 
-    foreach (item, selected) {
+    for (QTableWidgetItem *item : selected) {
         bool ok;
         double value = item->text().toDouble(&ok);
 
@@ -140,12 +139,11 @@ void MainWindow::averageItems()
 void MainWindow::sumItems()
 {
 //! [4]
-    QList<QTableWidgetItem *> selected = tableWidget->selectedItems();
-    QTableWidgetItem *item;
+    const QList<QTableWidgetItem *> selected = tableWidget->selectedItems();
     int number = 0;
     double total = 0;
 
-    foreach (item, selected) {
+    for (QTableWidgetItem *item : selected) {
         bool ok;
         double value = item->text().toDouble(&ok);
 
diff --git a/src/widgets/doc/snippets/qtreewidget-using/mainwindow.cpp b/src/widgets/doc/snippets/qtreewidget-using/mainwindow.cpp
index 7c8d3f936e..b9e258cb03 100644
--- a/src/widgets/doc/snippets/qtreewidget-using/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qtreewidget-using/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -90,16 +90,15 @@ MainWindow::MainWindow()
     treeWidget->setHeaderLabels(headers);
 //! [2]
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
-    connect(ascendingAction, SIGNAL(triggered()), this, SLOT(sortAscending()));
-    connect(autoSortAction, SIGNAL(triggered()), this, SLOT(updateSortItems()));
-    connect(descendingAction, SIGNAL(triggered()), this, SLOT(sortDescending()));
-    connect(findItemsAction, SIGNAL(triggered()), this, SLOT(findItems()));
-    connect(insertAction, SIGNAL(triggered()), this, SLOT(insertItem()));
-    connect(removeAction, SIGNAL(triggered()), this, SLOT(removeItem()));
-    connect(treeWidget,
-            SIGNAL(currentItemChanged(QTreeWidgetItem*,QTreeWidgetItem*)),
-            this, SLOT(updateMenus(QTreeWidgetItem*)));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
+    connect(ascendingAction, &QAction::triggered, this, &MainWindow::sortAscending);
+    connect(autoSortAction, &QAction::triggered, this, &MainWindow::updateSortItems);
+    connect(descendingAction, &QAction::triggered, this, &MainWindow::sortDescending);
+    connect(findItemsAction, &QAction::triggered, this, &MainWindow::findItems);
+    connect(insertAction, &QAction::triggered, this, &MainWindow::insertItem);
+    connect(removeAction, &QAction::triggered, this, &MainWindow::removeItem);
+    connect(treeWidget, &QTreeWidget::currentItemChanged,
+            this, &MainWindow::updateMenus);
 
     setupTreeItems();
     updateMenus(treeWidget->currentItem());
@@ -150,17 +149,15 @@ void MainWindow::findItems()
     if (itemText.isEmpty())
         return;
 
-//! [6]
-    QTreeWidgetItem *item;
-//! [6]
-    foreach (item, treeWidget->selectedItems())
+    const QList<QTreeWidgetItem *> items = treeWidget->selectedItems();
+    for (QTreeWidgetItem *item : items)
         item->setSelected(false);
 
 //! [7]
-    QList<QTreeWidgetItem *> found = treeWidget->findItems(
+    const QList<QTreeWidgetItem *> found = treeWidget->findItems(
         itemText, Qt::MatchWildcard);
 
-    foreach (item, found) {
+    for (QTreeWidgetItem *item : found) {
         item->setSelected(true);
         // Show the item->text(0) for each item.
     }
diff --git a/src/widgets/doc/snippets/qtreewidgetitemiterator-using/mainwindow.cpp b/src/widgets/doc/snippets/qtreewidgetitemiterator-using/mainwindow.cpp
index 5f1f606185..bfe099bbb4 100644
--- a/src/widgets/doc/snippets/qtreewidgetitemiterator-using/mainwindow.cpp
+++ b/src/widgets/doc/snippets/qtreewidgetitemiterator-using/mainwindow.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "mainwindow.h"
 
@@ -85,16 +85,15 @@ MainWindow::MainWindow()
     headers << tr("Subject") << tr("Default");
     treeWidget->setHeaderLabels(headers);
 
-    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
-    connect(ascendingAction, SIGNAL(triggered()), this, SLOT(sortAscending()));
-    connect(autoSortAction, SIGNAL(triggered()), this, SLOT(updateSortItems()));
-    connect(descendingAction, SIGNAL(triggered()), this, SLOT(sortDescending()));
-    connect(findItemsAction, SIGNAL(triggered()), this, SLOT(findItems()));
-    connect(insertAction, SIGNAL(triggered()), this, SLOT(insertItem()));
-    connect(removeAction, SIGNAL(triggered()), this, SLOT(removeItem()));
-    connect(treeWidget,
-            SIGNAL(currentItemChanged(QTreeWidgetItem*,QTreeWidgetItem*)),
-            this, SLOT(updateMenus(QTreeWidgetItem*)));
+    connect(quitAction, &QAction::triggered, this, &QWidget::close);
+    connect(ascendingAction, &QAction::triggered, this, &MainWindow::sortAscending);
+    connect(autoSortAction, &QAction::triggered, this, &MainWindow::updateSortItems);
+    connect(descendingAction, &QAction::triggered, this, &MainWindow::sortDescending);
+    connect(findItemsAction, &QAction::triggered, this, &MainWindow::findItems);
+    connect(insertAction, &QAction::triggered, this, &MainWindow::insertItem);
+    connect(removeAction, &QAction::triggered, this, &MainWindow::removeItem);
+    connect(treeWidget, &QTreeWidget::currentItemChanged,
+            this, &MainWindow::updateMenus);
 
     setupTreeItems();
     updateMenus(treeWidget->currentItem());
diff --git a/src/widgets/doc/snippets/reading-selections/window.cpp b/src/widgets/doc/snippets/reading-selections/window.cpp
index 08805fe4b3..045d66a199 100644
--- a/src/widgets/doc/snippets/reading-selections/window.cpp
+++ b/src/widgets/doc/snippets/reading-selections/window.cpp
@@ -81,9 +81,9 @@ MainWindow::MainWindow(QWidget *parent)
     QAction *selectAllAction = actionMenu->addAction(tr("&Select All"));
     menuBar()->addMenu(actionMenu);
 
-    connect(fillAction, SIGNAL(triggered()), this, SLOT(fillSelection()));
-    connect(clearAction, SIGNAL(triggered()), this, SLOT(clearSelection()));
-    connect(selectAllAction, SIGNAL(triggered()), this, SLOT(selectAll()));
+    connect(fillAction, &QAction::triggered, this, &MainWindow::fillSelection);
+    connect(clearAction, &QAction::triggered, this, &MainWindow::clearSelection);
+    connect(selectAllAction, &QAction::triggered, this, &MainWindow::selectAll);
 
     selectionModel = table->selectionModel();
 
@@ -94,10 +94,9 @@ MainWindow::MainWindow(QWidget *parent)
 void MainWindow::fillSelection()
 {
 //! [0]
-    QModelIndexList indexes = selectionModel->selectedIndexes();
-    QModelIndex index;
+    const QModelIndexList indexes = selectionModel->selectedIndexes();
 
-    foreach(index, indexes) {
+    for (const QModelIndex &index : indexes) {
         QString text = QString("(%1,%2)").arg(index.row()).arg(index.column());
         model->setData(index, text);
     }
@@ -106,11 +105,10 @@ void MainWindow::fillSelection()
 
 void MainWindow::clearSelection()
 {
-    QModelIndexList indexes = selectionModel->selectedIndexes();
-    QModelIndex index;
+    const QModelIndexList indexes = selectionModel->selectedIndexes();
 
-    foreach(index, indexes)
-        model->setData(index, "");
+    for (const QModelIndex &index : indexes)
+        model->setData(index, QString());
 }
 
 void MainWindow::selectAll()
diff --git a/src/widgets/doc/snippets/updating-selections/window.cpp b/src/widgets/doc/snippets/updating-selections/window.cpp
index 0bdcf8a64d..26e9b56ae4 100644
--- a/src/widgets/doc/snippets/updating-selections/window.cpp
+++ b/src/widgets/doc/snippets/updating-selections/window.cpp
@@ -74,12 +74,10 @@ MainWindow::MainWindow(QWidget *parent)
     table->setModel(model);
 
     selectionModel = table->selectionModel();
-    connect(selectionModel,
-        SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
-        this, SLOT(updateSelection(QItemSelection,QItemSelection)));
-    connect(selectionModel,
-        SIGNAL(currentChanged(QModelIndex,QModelIndex)),
-        this, SLOT(changeCurrent(QModelIndex,QModelIndex)));
+    connect(selectionModel, &QItemSelectionModel::selectionChanged,
+            this, &MainWindow::updateSelection);
+    connect(selectionModel, &QItemSelectionModel::currentChanged,
+            this, &MainWindow::changeCurrent);
 
     statusBar();
     setCentralWidget(table);
@@ -89,10 +87,9 @@ MainWindow::MainWindow(QWidget *parent)
 void MainWindow::updateSelection(const QItemSelection &selected,
     const QItemSelection &deselected)
 {
-    QModelIndex index;
     QModelIndexList items = selected.indexes();
 
-    foreach (index, items) {
+    for (const QModelIndex &index : qAsConst(items)) {
         QString text = QString("(%1,%2)").arg(index.row()).arg(index.column());
         model->setData(index, text);
 //! [0] //! [1]
@@ -102,8 +99,8 @@ void MainWindow::updateSelection(const QItemSelection &selected,
 //! [2]
     items = deselected.indexes();
 
-    foreach (index, items)
-        model->setData(index, "");
+    for (const QModelIndex &index : qAsConst(items)) {
+        model->setData(index, QString());
 }
 //! [2]