move object construction to initialization list

components/slider.cpp

@@ -6,12 +6,27 @@
 #include <QMouseEvent>
 #include <QApplication>
 
+SliderPrivate::SliderPrivate(Slider *q)
+    : q_ptr(q),
+      thumb(new SliderThumb(q)),
+      track(new SliderTrack(q)),
+      machine(0),
+      hoverTrack(false),
+      hoverThumb(false),
+      hover(false),
+      step(false),
+      pageStepMode(true),
+      stepTo(0),
+      oldValue(0),
+      trackWidth(2),
+      useThemeColors(true)
+{
+}
+
 void SliderPrivate::init()
 {
     Q_Q(Slider);
 
-    thumb = new SliderThumb(q);
-    track = new SliderTrack(q);
     machine = new SliderStateMachine(q, thumb, track);
 
     oldValue = q->value();

components/slider_p.h

@@ -13,18 +13,7 @@ class SliderPrivate
     Q_DECLARE_PUBLIC(Slider)
 
 public:
-    SliderPrivate(Slider *q)
-        : q_ptr(q),
-          hoverTrack(false),
-          hoverThumb(false),
-          hover(false),
-          step(false),
-          pageStepMode(true),
-          stepTo(0),
-          oldValue(0),
-          trackWidth(2),
-          useThemeColors(true)
-    {}
+    SliderPrivate(Slider *q);
 
     void init();
 
@@ -36,8 +25,8 @@ public:
     void setHovered(bool status);
 
     Slider             *const q_ptr;
-    SliderThumb *thumb;
-    SliderTrack *track;
+    SliderThumb        *const thumb;
+    SliderTrack        *const track;
     SliderStateMachine *machine;
     bool                hoverTrack;
     bool                hoverThumb;