replaced pointer by smart pointers

mainwindow.cpp

@@ -43,7 +43,7 @@ MainWindow::MainWindow(QWidget * parent)
     QObject::connect(startRennen, SIGNAL(activated()), this,
                      SLOT(WindowRennen()));
 
-    this->db = new DataBase;
+    this->db = std::make_shared<DataBase>();
 
     // vector<vector<QString>> daten = db->getData("select * from Fahrer", 2);
 }
@@ -52,17 +52,18 @@ void MainWindow::closeEvent(QCloseEvent * event) {
 }
 
 MainWindow::~MainWindow() {
-    delete this->db;
     delete ui;
 }
 
 void MainWindow::WindowTraining() {
-    this->interfaceTraining = new Training(this, this->db);
+    // this->interfaceTraining = new Training(this, this->db);
+    this->interfaceTraining = std::make_shared<Training>(this, this->db);
     this->interfaceTraining->show();
 }
 
 void MainWindow::NewWindowSettings() {
-    this->interfaceSettings = new WindowsSettings(this->db, this);
+    this->interfaceSettings =
+        std::make_shared<WindowsSettings>(this->db.get(), this);
     this->interfaceSettings->show();
 }
 
@@ -107,15 +108,16 @@ void MainWindow::WindowRennen() {
         Q_UNUSED(e);
     }
 
-    this->interfaceRace = new WindowRace(this->db, this);
+    this->interfaceRace = std::make_shared<WindowRace>(this->db, this);
     this->interfaceRace->show();
-    this->interfaceRennliste = new WindowRennliste(this->db, this);
+    this->interfaceRennliste =
+        std::make_shared<WindowRennliste>(this->db.get(), this);
     this->interfaceRennliste->show();
     this->interfaceRace->setWindowRennliste(this->interfaceRennliste);
-    this->interfaceRennliste->setWindowRace(this->interfaceRace);
+    this->interfaceRennliste->setWindowRace(this->interfaceRace.get());
 }
 
 void MainWindow::WindowEvaluation() {
-    this->interfaceEvaluation = new Evaluation(this->db);
+    this->interfaceEvaluation = std::make_shared<Evaluation>(this->db.get());
     this->interfaceEvaluation->show();
 }