Cleanup QtWidgets (widgets) examples

Cleanup QtWidgets widgets examples:
 - use member-init (clang-tidy)
 - fix includes/don't include QtWidgets globally
 - include own header first
 - use nullptr (clang-tidy)
 - avoid c-style casts
 - use QVector instead QList

Change-Id: Ib56bb507eb2ef885f1ddc664050d3c7af92adb70
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

2 files changed, 11 insertions, 13 deletions

diff --git a/examples/widgets/widgets/calculator/button.cpp b/examples/widgets/widgets/calculator/button.cpp
index a1ce0bf428..cc370a563c 100644
--- a/examples/widgets/widgets/calculator/button.cpp
+++ b/examples/widgets/widgets/calculator/button.cpp
@@ -50,8 +50,6 @@
 
 #include "button.h"
 
-#include <QtWidgets>
-
 //! [0]
 Button::Button(const QString &text, QWidget *parent)
     : QToolButton(parent)
diff --git a/examples/widgets/widgets/calculator/calculator.cpp b/examples/widgets/widgets/calculator/calculator.cpp
index dd908cf40a..2c3669b7a8 100644
--- a/examples/widgets/widgets/calculator/calculator.cpp
+++ b/examples/widgets/widgets/calculator/calculator.cpp
@@ -48,21 +48,18 @@
 **
 ****************************************************************************/
 
-#include "button.h"
 #include "calculator.h"
+#include "button.h"
 
-#include <QtWidgets>
-
-#include <cmath>
+#include <QGridLayout>
+#include <QLineEdit>
+#include <QtMath>
 
 //! [0]
 Calculator::Calculator(QWidget *parent)
-    : QWidget(parent)
+    : QWidget(parent), sumInMemory(0.0), sumSoFar(0.0)
+    , factorSoFar(0.0), waitingForOperand(true)
 {
-    sumInMemory = 0.0;
-    sumSoFar = 0.0;
-    factorSoFar = 0.0;
-    waitingForOperand = true;
 //! [0]
 
 //! [1]
@@ -78,9 +75,8 @@ Calculator::Calculator(QWidget *parent)
 //! [2]
 
 //! [4]
-    for (int i = 0; i < NumDigitButtons; ++i) {
+    for (int i = 0; i < NumDigitButtons; ++i)
         digitButtons[i] = createButton(QString::number(i), SLOT(digitClicked()));
-    }
 
     Button *pointButton = createButton(tr("."), SLOT(pointClicked()));
     Button *changeSignButton = createButton(tr("\302\261"), SLOT(changeSignClicked()));
@@ -194,6 +190,8 @@ void Calculator::additiveOperatorClicked()
 //! [10] //! [11]
 {
     Button *clickedButton = qobject_cast<Button *>(sender());
+    if (!clickedButton)
+      return;
     QString clickedOperator = clickedButton->text();
     double operand = display->text().toDouble();
 
@@ -233,6 +231,8 @@ void Calculator::additiveOperatorClicked()
 void Calculator::multiplicativeOperatorClicked()
 {
     Button *clickedButton = qobject_cast<Button *>(sender());
+    if (!clickedButton)
+      return;
     QString clickedOperator = clickedButton->text();
     double operand = display->text().toDouble();