diff --git a/src/gui/basketmodel.cpp b/src/gui/basketmodel.cpp
index d693782..789d64b 100644
--- a/src/gui/basketmodel.cpp
+++ b/src/gui/basketmodel.cpp
@@ -5,13 +5,13 @@
 #include <QSettings>
 
 BasketModel::BasketModel(Marketplace* market, QObject* parent)
-    : QAbstractTableModel(parent), marketplace_(market)
+    : QAbstractTableModel(parent), m_marketplace(market)
 {
 }
 
 int BasketModel::rowCount([[maybe_unused]] const QModelIndex& parent) const
 {
-    return static_cast<int>(marketplace_->basketSize());
+    return static_cast<int>(m_marketplace->basketSize());
 }
 
 int BasketModel::columnCount([[maybe_unused]] const QModelIndex& parent) const { return 4; }
@@ -46,10 +46,10 @@ QVariant BasketModel::data(const QModelIndex& index, int role) const
     if (role != Qt::DisplayRole)
         return QVariant();
 
-    if (marketplace_->basketSize() == 0)
+    if (m_marketplace->basketSize() == 0)
         return QVariant();
 
-    Article* article = marketplace_->getBasket().at(index.row()).get();
+    Article* article = m_marketplace->getBasket().at(index.row()).get();
 
     switch (index.column()) {
     case 0:
@@ -92,45 +92,45 @@ QVariant BasketModel::headerData(int section, Qt::Orientation orientation, int r
 
 void BasketModel::addArticle(Seller* seller, int price, const std::string& desc)
 {
-    emit beginInsertRows(QModelIndex(), marketplace_->getBasket().size(),
-                         marketplace_->getBasket().size());
+    emit beginInsertRows(QModelIndex(), m_marketplace->getBasket().size(),
+                         m_marketplace->getBasket().size());
     auto article = std::make_unique<Article>(price);
     article->createUuid();
     article->setDescription(desc);
-    article->setArticleNo(marketplace_->getNextArticleNo());
+    article->setArticleNo(m_marketplace->getNextArticleNo());
     article->setSourceNo(QSettings().value("global/cashPointNo").toInt());
     article->setSeller(seller);
-    marketplace_->addArticleToBasket(std::move(article));
+    m_marketplace->addArticleToBasket(std::move(article));
     emit endInsertRows();
 }
 
 void BasketModel::finishSale()
 {
-    emit beginRemoveRows(QModelIndex(), 0, marketplace_->getBasket().size() - 1);
+    emit beginRemoveRows(QModelIndex(), 0, m_marketplace->getBasket().size() - 1);
     auto sale = std::make_unique<Sale>();
     sale->createUuid();
     sale->setSourceNo(QSettings().value("global/cashPointNo").toInt());
-    marketplace_->finishCurrentSale(std::move(sale));
+    m_marketplace->finishCurrentSale(std::move(sale));
     emit endRemoveRows();
     emit basketDataChanged();
 }
 
 void BasketModel::cancelSale()
 {
-    emit beginRemoveRows(QModelIndex(), 0, marketplace_->getBasket().size() - 1);
-    marketplace_->getBasket().clear();
+    emit beginRemoveRows(QModelIndex(), 0, m_marketplace->getBasket().size() - 1);
+    m_marketplace->getBasket().clear();
     emit endRemoveRows();
 }
 
 bool BasketModel::removeRows(int row, int count, const QModelIndex& parent)
 {
-    auto article = marketplace_->getBasket().at(row).get();
+    auto article = m_marketplace->getBasket().at(row).get();
 
     emit beginRemoveRows(parent, row, row + count - 1);
-    marketplace_->getBasket().erase(
-        std::remove_if(marketplace_->getBasket().begin(), marketplace_->getBasket().end(),
+    m_marketplace->getBasket().erase(
+        std::remove_if(m_marketplace->getBasket().begin(), m_marketplace->getBasket().end(),
                        [&article](const auto& a) { return a->getUuid() == article->getUuid(); }),
-        marketplace_->getBasket().end());
+        m_marketplace->getBasket().end());
     emit endRemoveRows();
     return true;
 }
diff --git a/src/gui/basketmodel.h b/src/gui/basketmodel.h
index 7c1858c..81ad858 100644
--- a/src/gui/basketmodel.h
+++ b/src/gui/basketmodel.h
@@ -24,7 +24,7 @@ class BasketModel : public QAbstractTableModel
     void basketDataChanged();
 
   private:
-    Marketplace* marketplace_;
+    Marketplace* m_marketplace;
 };
 
 #endif
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index f078b1e..c69da27 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -32,10 +32,10 @@ constexpr int STATUSBAR_TIMEOUT = 5000;
 
 MainWindow::MainWindow()
 {
-    ui_.setupUi(this);
+    m_ui.setupUi(this);
 
-    marketplace_ = std::make_unique<Marketplace>();
-    Database::InitResult res = marketplace_->loadFromDb();
+    m_marketplace = std::make_unique<Marketplace>();
+    Database::InitResult res = m_marketplace->loadFromDb();
     if (res == Database::InitResult::OUTDATED_REPLACED) {
         QMessageBox(QMessageBox::Icon::Information, "Datenbankinformation",
                     "Es wurde eine <b>veraltete</b> Datenbankdatei erkannt.<br />Diese wurde "
@@ -44,19 +44,19 @@ MainWindow::MainWindow()
     }
     statusBar()->showMessage("Gespeicherte Daten wurden geladen.", STATUSBAR_TIMEOUT);
 
-    BasketModel *model = new BasketModel(getMarketplace(), ui_.basketView);
-    ui_.basketView->setModel(model);
-    ui_.basketView->setColumnHidden(0, true); // hide the uuid
+    BasketModel *model = new BasketModel(getMarketplace(), m_ui.basketView);
+    m_ui.basketView->setModel(model);
+    m_ui.basketView->setColumnHidden(0, true); // hide the uuid
 
     setWindowTitle("KIMA2 - Kasse Nr. " + QSettings().value("global/cashPointNo").toString());
 
-    ui_.salesView->header()->setSectionResizeMode(QHeaderView::ResizeToContents);
+    m_ui.salesView->header()->setSectionResizeMode(QHeaderView::ResizeToContents);
     setSaleModel();
 
-    connect(ui_.actionQuit, &QAction::triggered, qApp, QApplication::closeAllWindows,
+    connect(m_ui.actionQuit, &QAction::triggered, qApp, QApplication::closeAllWindows,
             Qt::QueuedConnection);
-    connect(ui_.newAction, &QAction::triggered, this, [this]() {
-        if (marketplace_->getSellers().size() == 0 && marketplace_->getSales().size() == 0) {
+    connect(m_ui.newAction, &QAction::triggered, this, [this]() {
+        if (m_marketplace->getSellers().size() == 0 && m_marketplace->getSales().size() == 0) {
             return;
         }
         auto dlgResult =
@@ -68,34 +68,34 @@ MainWindow::MainWindow()
         if (dlgResult == QMessageBox::No)
             return;
 
-        delete ui_.salesView->model();
-        dynamic_cast<BasketModel *>(ui_.basketView->model())->cancelSale();
-        marketplace_->clear();
+        delete m_ui.salesView->model();
+        dynamic_cast<BasketModel *>(m_ui.basketView->model())->cancelSale();
+        m_marketplace->clear();
         setSaleModel();
         updateStatLabel();
     });
 
-    ui_.sellerNoEdit->installEventFilter(this);
-    ui_.givenSpinBox->installEventFilter(this);
+    m_ui.sellerNoEdit->installEventFilter(this);
+    m_ui.givenSpinBox->installEventFilter(this);
 
-    connect(ui_.actionEditSeller, &QAction::triggered, this,
+    connect(m_ui.actionEditSeller, &QAction::triggered, this,
             &MainWindow::onActionEditSellerTriggered);
-    connect(ui_.paidButton, &QPushButton::clicked, this, &MainWindow::onPaidButtonTriggered);
-    connect(ui_.givenSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged), this,
+    connect(m_ui.paidButton, &QPushButton::clicked, this, &MainWindow::onPaidButtonTriggered);
+    connect(m_ui.givenSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged), this,
             &MainWindow::onGivenSpinBoxValueChanged);
-    connect(ui_.basketView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
+    connect(m_ui.basketView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
             &MainWindow::onBasketViewSelectionChanged);
-    connect(ui_.cancelArticleButton, &QPushButton::clicked, this,
+    connect(m_ui.cancelArticleButton, &QPushButton::clicked, this,
             &MainWindow::onCancelArticleButtonClicked);
-    connect(ui_.cancelSaleButton, &QPushButton::clicked, this,
+    connect(m_ui.cancelSaleButton, &QPushButton::clicked, this,
             &MainWindow::onCancelSaleButtonClicked);
-    connect(ui_.printSaleReceiptButton, &QPushButton::clicked, this,
+    connect(m_ui.printSaleReceiptButton, &QPushButton::clicked, this,
             &MainWindow::onPrintSaleReceiptButtonClicked);
-    connect(ui_.cancelAllArticlesButton, &QPushButton::clicked, this,
+    connect(m_ui.cancelAllArticlesButton, &QPushButton::clicked, this,
             &MainWindow::onCancelAllArticlesButtonClicked);
-    connect(ui_.aboutQtAction, &QAction::triggered, this, &MainWindow::onAboutQt);
-    connect(ui_.aboutAction, &QAction::triggered, this, &MainWindow::onAbout);
-    connect(ui_.openManualAction, &QAction::triggered, this, []() {
+    connect(m_ui.aboutQtAction, &QAction::triggered, this, &MainWindow::onAboutQt);
+    connect(m_ui.aboutAction, &QAction::triggered, this, &MainWindow::onAbout);
+    connect(m_ui.openManualAction, &QAction::triggered, this, []() {
         auto locations = QStandardPaths::standardLocations(QStandardPaths::DataLocation);
         for (auto location : locations) {
             if (QFile::exists(location + QString("/Benutzerhandbuch.pdf"))) {
@@ -105,7 +105,7 @@ MainWindow::MainWindow()
             }
         }
     });
-    connect(ui_.licenseAction, &QAction::triggered, this, [this]() {
+    connect(m_ui.licenseAction, &QAction::triggered, this, [this]() {
         QString licenseText(
             "Copyright © 2018-2022 Martin Brodbeck\n\n"
             "Hiermit wird unentgeltlich jeder Person, die eine Kopie der Software und der "
@@ -126,34 +126,34 @@ MainWindow::MainWindow()
             "SOFTWARE ODER SONSTIGER VERWENDUNG DER SOFTWARE ENTSTANDEN.");
         QMessageBox::information(this, "Lizenzinformation", licenseText);
     });
-    connect(ui_.reportAction, &QAction::triggered, this, [this]() { ReportDialog(this).exec(); });
-    connect(ui_.configAction, &QAction::triggered, this, [this]() {
+    connect(m_ui.reportAction, &QAction::triggered, this, [this]() { ReportDialog(this).exec(); });
+    connect(m_ui.configAction, &QAction::triggered, this, [this]() {
         int result = SettingsDialog(this).exec();
         if (result == QDialog::Accepted) {
-            delete ui_.salesView->model();
-            marketplace_->loadFromDb();
+            delete m_ui.salesView->model();
+            m_marketplace->loadFromDb();
             setSaleModel();
         }
         this->setWindowTitle("KIMA2 - Kasse Nr. " +
                              QSettings().value("global/cashPointNo").toString());
     });
-    connect(ui_.importSellerExcelAction, &QAction::triggered, this,
+    connect(m_ui.importSellerExcelAction, &QAction::triggered, this,
             &MainWindow::onImportSellerExcelActionTriggered);
-    connect(ui_.importSellerJsonAction, &QAction::triggered, this,
+    connect(m_ui.importSellerJsonAction, &QAction::triggered, this,
             &MainWindow::onImportSellerJsonActionTriggered);
-    connect(ui_.exportSellerJsonAction, &QAction::triggered, this,
+    connect(m_ui.exportSellerJsonAction, &QAction::triggered, this,
             &MainWindow::onExportSellerJsonActionTriggered);
-    connect(ui_.exportSalesJsonAction, &QAction::triggered, this,
+    connect(m_ui.exportSalesJsonAction, &QAction::triggered, this,
             &MainWindow::onExportSalesJsonActionTriggered);
-    connect(ui_.importSalesJsonAction, &QAction::triggered, this,
+    connect(m_ui.importSalesJsonAction, &QAction::triggered, this,
             &MainWindow::onImportSalesJsonActionTriggered);
 
     readGeometry();
     setWindowIcon(QIcon(":/misc/kima2.ico"));
 
     updateStatLabel();
-    ui_.lastPriceLabel1->setText(formatCentAsEuroString(0).c_str());
-    ui_.lastPriceLabel2->setText(formatCentAsEuroString(0).c_str());
+    m_ui.lastPriceLabel1->setText(formatCentAsEuroString(0).c_str());
+    m_ui.lastPriceLabel2->setText(formatCentAsEuroString(0).c_str());
 }
 
 void MainWindow::onActionEditSellerTriggered()
@@ -161,11 +161,11 @@ void MainWindow::onActionEditSellerTriggered()
     auto dialog = std::make_unique<SellerDialog>(this);
     int retCode = dialog->exec();
 
-    delete ui_.salesView->model();
+    delete m_ui.salesView->model();
 
     if (retCode == QDialog::Accepted) {
-        marketplace_->sortSellers();
-        marketplace_->storeToDb();
+        m_marketplace->sortSellers();
+        m_marketplace->storeToDb();
         statusBar()->showMessage("Änderungen an den Verkäufer-Stammdaten gespeichert.",
                                  STATUSBAR_TIMEOUT);
     } else {
@@ -179,32 +179,32 @@ void MainWindow::onActionEditSellerTriggered()
 
 void MainWindow::setSaleModel()
 {
-    ui_.salesView->setModel(new SaleModel(getMarketplace(), ui_.salesView));
-    ui_.salesView->setColumnHidden(2, true);
-    ui_.salesView->resizeColumnToContents(0);
-    ui_.salesView->resizeColumnToContents(1);
+    m_ui.salesView->setModel(new SaleModel(getMarketplace(), m_ui.salesView));
+    m_ui.salesView->setColumnHidden(2, true);
+    m_ui.salesView->resizeColumnToContents(0);
+    m_ui.salesView->resizeColumnToContents(1);
 
-    ui_.printSaleReceiptButton->setEnabled(false);
-    ui_.cancelSaleButton->setEnabled(false);
+    m_ui.printSaleReceiptButton->setEnabled(false);
+    m_ui.cancelSaleButton->setEnabled(false);
 
-    connect(static_cast<BasketModel *>(ui_.basketView->model()), &BasketModel::basketDataChanged,
-            static_cast<SaleModel *>(ui_.salesView->model()), &SaleModel::onBasketDataChanged);
-    connect(ui_.salesView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
+    connect(static_cast<BasketModel *>(m_ui.basketView->model()), &BasketModel::basketDataChanged,
+            static_cast<SaleModel *>(m_ui.salesView->model()), &SaleModel::onBasketDataChanged);
+    connect(m_ui.salesView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
             &MainWindow::onSalesViewSelectionChanged);
 }
 
 void MainWindow::onPaidButtonTriggered()
 {
-    if (marketplace_->basketSize() > 0) {
-        QString lastPrice{marketplace_->getBasketSumAsString().c_str()};
-        dynamic_cast<BasketModel *>(ui_.basketView->model())->finishSale();
-        ui_.salesView->resizeColumnToContents(0);
-        ui_.lastPriceLabel1->setText(lastPrice);
-        ui_.lastPriceLabel2->setText(lastPrice);
-        ui_.basketSumLabel->setText(formatCentAsEuroString(0).c_str());
-        ui_.drawbackLabel->setText(formatCentAsEuroString(0).c_str());
-        ui_.drawbackContainerWidget->setEnabled(false);
-        ui_.sellerNoEdit->setFocus();
+    if (m_marketplace->basketSize() > 0) {
+        QString lastPrice{m_marketplace->getBasketSumAsString().c_str()};
+        dynamic_cast<BasketModel *>(m_ui.basketView->model())->finishSale();
+        m_ui.salesView->resizeColumnToContents(0);
+        m_ui.lastPriceLabel1->setText(lastPrice);
+        m_ui.lastPriceLabel2->setText(lastPrice);
+        m_ui.basketSumLabel->setText(formatCentAsEuroString(0).c_str());
+        m_ui.drawbackLabel->setText(formatCentAsEuroString(0).c_str());
+        m_ui.drawbackContainerWidget->setEnabled(false);
+        m_ui.sellerNoEdit->setFocus();
         statusBar()->showMessage("Verkaufsvorgang erfolgreich durchgeführt.", STATUSBAR_TIMEOUT);
         updateStatLabel();
     }
@@ -212,7 +212,7 @@ void MainWindow::onPaidButtonTriggered()
 
 bool MainWindow::eventFilter(QObject *target, QEvent *event)
 {
-    if (target == ui_.sellerNoEdit) {
+    if (target == m_ui.sellerNoEdit) {
         if (event->type() == QEvent::KeyPress) {
             QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
             if (keyEvent->key() == Qt::Key::Key_Enter || keyEvent->key() == Qt::Key::Key_Return) {
@@ -225,7 +225,7 @@ bool MainWindow::eventFilter(QObject *target, QEvent *event)
                 return true;
             }
         }
-    } else if (target == ui_.givenSpinBox) {
+    } else if (target == m_ui.givenSpinBox) {
         if (event->type() == QEvent::KeyPress) {
             QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
             if (keyEvent->key() == Qt::Key::Key_Enter || keyEvent->key() == Qt::Key::Key_Return) {
@@ -234,9 +234,9 @@ bool MainWindow::eventFilter(QObject *target, QEvent *event)
                     return true;
                 }
             } else if (keyEvent->key() == Qt::Key::Key_Escape) {
-                ui_.drawbackLabel->setText(formatCentAsEuroString(0).c_str());
-                ui_.drawbackContainerWidget->setEnabled(false);
-                ui_.sellerNoEdit->setFocus();
+                m_ui.drawbackLabel->setText(formatCentAsEuroString(0).c_str());
+                m_ui.drawbackContainerWidget->setEnabled(false);
+                m_ui.sellerNoEdit->setFocus();
             }
         }
     }
@@ -247,15 +247,15 @@ void MainWindow::checkSellerNo(bool ctrlPressed)
 {
     using std::regex, std::regex_match, std::smatch;
 
-    auto inputText = ui_.sellerNoEdit->text().toStdString();
+    auto inputText = m_ui.sellerNoEdit->text().toStdString();
 
     if (inputText.empty()) {
         if (ctrlPressed == false) {
             onPaidButtonTriggered();
-        } else if (marketplace_->getBasket().size() > 0) {
-            ui_.drawbackContainerWidget->setEnabled(true);
-            ui_.givenSpinBox->setFocus();
-            ui_.givenSpinBox->selectAll();
+        } else if (m_marketplace->getBasket().size() > 0) {
+            m_ui.drawbackContainerWidget->setEnabled(true);
+            m_ui.givenSpinBox->setFocus();
+            m_ui.givenSpinBox->selectAll();
         }
         return;
     }
@@ -264,13 +264,13 @@ void MainWindow::checkSellerNo(bool ctrlPressed)
     smatch result;
 
     if (!regex_match(inputText, result, pattern)) {
-        ui_.sellerNoEdit->clear();
+        m_ui.sellerNoEdit->clear();
         return;
     }
 
     int sellerNo = std::stoi(result[0]);
 
-    auto seller = marketplace_->findSellerWithSellerNo(sellerNo);
+    auto seller = m_marketplace->findSellerWithSellerNo(sellerNo);
     if (seller) {
         PriceDialog priceDialog(this);
         if (sellerNo == 0) {
@@ -280,30 +280,30 @@ void MainWindow::checkSellerNo(bool ctrlPressed)
         if (dialogResult == QDialog::Accepted) {
             int price = priceDialog.getPrice();
             std::string desc = priceDialog.getDescription();
-            dynamic_cast<BasketModel *>(ui_.basketView->model())->addArticle(seller, price, desc);
-            ui_.basketView->resizeColumnToContents(1);
-            ui_.basketSumLabel->setText(marketplace_->getBasketSumAsString().c_str());
+            dynamic_cast<BasketModel *>(m_ui.basketView->model())->addArticle(seller, price, desc);
+            m_ui.basketView->resizeColumnToContents(1);
+            m_ui.basketSumLabel->setText(m_marketplace->getBasketSumAsString().c_str());
         }
     }
 
-    ui_.sellerNoEdit->clear();
+    m_ui.sellerNoEdit->clear();
 }
 
 void MainWindow::onGivenSpinBoxValueChanged(double value)
 {
     int givenInCent = std::round(value * 100);
-    int basketSumInCent = marketplace_->getBasketSumInCent();
+    int basketSumInCent = m_marketplace->getBasketSumInCent();
     int drawback = givenInCent - basketSumInCent;
-    ui_.drawbackLabel->setText(formatCentAsEuroString(drawback).c_str());
+    m_ui.drawbackLabel->setText(formatCentAsEuroString(drawback).c_str());
 }
 
 void MainWindow::onBasketViewSelectionChanged(const QItemSelection &selected,
                                               [[maybe_unused]] const QItemSelection &deselected)
 {
     if (selected.size() > 0) {
-        ui_.cancelArticleButton->setEnabled(true);
+        m_ui.cancelArticleButton->setEnabled(true);
     } else {
-        ui_.cancelArticleButton->setEnabled(false);
+        m_ui.cancelArticleButton->setEnabled(false);
     }
 }
 
@@ -311,21 +311,21 @@ void MainWindow::onSalesViewSelectionChanged(const QItemSelection &selected,
                                              [[maybe_unused]] const QItemSelection &deselected)
 {
     if (selected.size() > 0) {
-        ui_.cancelSaleButton->setEnabled(true);
+        m_ui.cancelSaleButton->setEnabled(true);
         if (!selected.indexes()[0].parent().isValid())
-            ui_.printSaleReceiptButton->setEnabled(true);
+            m_ui.printSaleReceiptButton->setEnabled(true);
         else
-            ui_.printSaleReceiptButton->setEnabled(false);
+            m_ui.printSaleReceiptButton->setEnabled(false);
 
     } else {
-        ui_.cancelSaleButton->setEnabled(false);
-        ui_.printSaleReceiptButton->setEnabled(false);
+        m_ui.cancelSaleButton->setEnabled(false);
+        m_ui.printSaleReceiptButton->setEnabled(false);
     }
 }
 
 void MainWindow::onCancelArticleButtonClicked([[maybe_unused]] bool checked)
 {
-    auto selModel = ui_.basketView->selectionModel();
+    auto selModel = m_ui.basketView->selectionModel();
     if (selModel->hasSelection() == false)
         return;
 
@@ -342,16 +342,16 @@ void MainWindow::onCancelArticleButtonClicked([[maybe_unused]] bool checked)
 
     // Deleting the rows, beginning with the last one!
     for (auto iter = indexes.constEnd() - 1; iter >= indexes.constBegin(); --iter) {
-        ui_.basketView->model()->removeRow(iter->row());
+        m_ui.basketView->model()->removeRow(iter->row());
     }
 
-    ui_.basketSumLabel->setText(marketplace_->getBasketSumAsString().c_str()); // Update basket sum
-    ui_.sellerNoEdit->setFocus();
+    m_ui.basketSumLabel->setText(m_marketplace->getBasketSumAsString().c_str()); // Update basket sum
+    m_ui.sellerNoEdit->setFocus();
 }
 
 void MainWindow::onCancelSaleButtonClicked([[maybe_unused]] bool checked)
 {
-    auto selModel = ui_.salesView->selectionModel();
+    auto selModel = m_ui.salesView->selectionModel();
     if (selModel->hasSelection() == false)
         return;
 
@@ -368,25 +368,25 @@ void MainWindow::onCancelSaleButtonClicked([[maybe_unused]] bool checked)
 
     // Deleting the rows, beginning with the last one!
     for (auto iter = indexes.constEnd() - 1; iter >= indexes.constBegin(); --iter) {
-        ui_.salesView->model()->removeRow(iter->row(), iter->parent());
+        m_ui.salesView->model()->removeRow(iter->row(), iter->parent());
     }
 
-    ui_.salesView->collapseAll();
+    m_ui.salesView->collapseAll();
 
     QString lastPriceValue(formatCentAsEuroString(0).c_str());
-    if (ui_.salesView->model()->rowCount() > 0) {
+    if (m_ui.salesView->model()->rowCount() > 0) {
         lastPriceValue =
-            ui_.salesView->model()->data(ui_.salesView->model()->index(0, 1)).toString();
+            m_ui.salesView->model()->data(m_ui.salesView->model()->index(0, 1)).toString();
     }
-    ui_.lastPriceLabel1->setText(lastPriceValue);
-    ui_.lastPriceLabel2->setText(lastPriceValue);
+    m_ui.lastPriceLabel1->setText(lastPriceValue);
+    m_ui.lastPriceLabel2->setText(lastPriceValue);
 
     updateStatLabel();
 }
 
 void MainWindow::onPrintSaleReceiptButtonClicked([[maybe_unused]] bool checked)
 {
-    auto selModel = ui_.salesView->selectionModel();
+    auto selModel = m_ui.salesView->selectionModel();
     if (selModel->hasSelection() == false)
         return;
 
@@ -395,7 +395,7 @@ void MainWindow::onPrintSaleReceiptButtonClicked([[maybe_unused]] bool checked)
     QString posPrinterEndpoint = settings.value("global/posPrinterEndpoint", "").toString();
 
     auto indexes = selModel->selectedRows();
-    auto &sale = marketplace_->getSales().at(indexes[0].row());
+    auto &sale = m_marketplace->getSales().at(indexes[0].row());
 
     auto printerDevice =
         convertToPosPrinterDevice(posPrinterDevice.toStdString(), posPrinterEndpoint.toStdString());
@@ -415,7 +415,7 @@ void MainWindow::onPrintSaleReceiptButtonClicked([[maybe_unused]] bool checked)
 
 void MainWindow::onCancelAllArticlesButtonClicked([[maybe_unused]] bool checked)
 {
-    if (ui_.basketView->model()->rowCount() == 0)
+    if (m_ui.basketView->model()->rowCount() == 0)
         return;
 
     auto dlgResult =
@@ -426,10 +426,10 @@ void MainWindow::onCancelAllArticlesButtonClicked([[maybe_unused]] bool checked)
     if (dlgResult == QMessageBox::No)
         return;
 
-    dynamic_cast<BasketModel *>(ui_.basketView->model())->cancelSale();
+    dynamic_cast<BasketModel *>(m_ui.basketView->model())->cancelSale();
 
-    ui_.basketSumLabel->setText(marketplace_->getBasketSumAsString().c_str()); // Update basket sum
-    ui_.sellerNoEdit->setFocus();
+    m_ui.basketSumLabel->setText(m_marketplace->getBasketSumAsString().c_str()); // Update basket sum
+    m_ui.sellerNoEdit->setFocus();
 }
 
 void MainWindow::onAboutQt() { QMessageBox::aboutQt(this); }
@@ -447,7 +447,7 @@ void MainWindow::onAbout()
 
 void MainWindow::onImportSellerExcelActionTriggered()
 {
-    if (!marketplace_->getSales().empty()) {
+    if (!m_marketplace->getSales().empty()) {
         QMessageBox(QMessageBox::Icon::Information, "Import nicht möglich",
                     "Der Import ist nicht möglich, da schon Verkäufe getätigt wurden.",
                     QMessageBox::StandardButton::Ok, this)
@@ -471,7 +471,7 @@ void MainWindow::onImportSellerExcelActionTriggered()
     std::size_t numImported{};
     if (case_insensitive_match(filePath.extension().string(), std::string(".xlsx"))) {
         try {
-            numImported = ExcelReader::readSellersFromFile(filePath, marketplace_.get());
+            numImported = ExcelReader::readSellersFromFile(filePath, m_marketplace.get());
         } catch (const std::exception &e) {
             QMessageBox(QMessageBox::Icon::Critical, "Fehler beim Importieren",
                         "Beim Import aus der Excel-Datei ist ein Fehler aufgetreten. "
@@ -482,7 +482,7 @@ void MainWindow::onImportSellerExcelActionTriggered()
             return;
         }
     } else {
-        numImported = CsvReader::readSellersFromFile(filePath, marketplace_.get());
+        numImported = CsvReader::readSellersFromFile(filePath, m_marketplace.get());
     }
 
     updateStatLabel();
@@ -498,7 +498,7 @@ void MainWindow::onImportSellerExcelActionTriggered()
 
 void MainWindow::onImportSellerJsonActionTriggered()
 {
-    if (!marketplace_->getSales().empty()) {
+    if (!m_marketplace->getSales().empty()) {
         QMessageBox(QMessageBox::Icon::Information, "Import nicht möglich",
                     "Der Import ist nicht möglich, da schon Verkäufe getätigt wurden.",
                     QMessageBox::StandardButton::Ok, this)
@@ -519,7 +519,7 @@ void MainWindow::onImportSellerJsonActionTriggered()
 #endif
 
     std::size_t numImported{};
-    numImported = JsonUtil::importSellers(filePath, marketplace_.get());
+    numImported = JsonUtil::importSellers(filePath, m_marketplace.get());
 
     updateStatLabel();
 
@@ -546,7 +546,7 @@ void MainWindow::onExportSellerJsonActionTriggered()
     fs::path filePath(filename.toStdString());
 #endif
 
-    JsonUtil::exportSellers(filePath, marketplace_.get());
+    JsonUtil::exportSellers(filePath, m_marketplace.get());
 }
 
 void MainWindow::onExportSalesJsonActionTriggered()
@@ -567,7 +567,7 @@ void MainWindow::onExportSalesJsonActionTriggered()
     fs::path filePath(filename.toStdString());
 #endif
 
-    JsonUtil::exportSales(filePath, marketplace_.get(),
+    JsonUtil::exportSales(filePath, m_marketplace.get(),
                           settings.value("global/cashPointNo").toInt());
 }
 
@@ -587,9 +587,9 @@ void MainWindow::onImportSalesJsonActionTriggered()
     fs::path filePath(filename.toStdString());
 #endif
 
-    delete ui_.salesView->model();
+    delete m_ui.salesView->model();
     try {
-        JsonUtil::importSales(filePath, marketplace_.get(),
+        JsonUtil::importSales(filePath, m_marketplace.get(),
                               settings.value("global/cashPointNo").toInt());
     } catch (std::runtime_error &err) {
         QMessageBox(QMessageBox::Icon::Warning, "Import nicht möglich", err.what(), QMessageBox::Ok,
@@ -630,9 +630,9 @@ void MainWindow::updateStatLabel()
 {
     std::string statistics("<b>KIMA2 - Version ");
     statistics += PROJECT_VERSION;
-    statistics += "</b><br />Verkäufer: " + std::to_string(marketplace_->getSellers().size() - 1);
-    statistics += "<br />Kunden: " + std::to_string(marketplace_->getSales().size());
-    statistics += "<br />Umsatz: " + marketplace_->getOverallSumAsString();
+    statistics += "</b><br />Verkäufer: " + std::to_string(m_marketplace->getSellers().size() - 1);
+    statistics += "<br />Kunden: " + std::to_string(m_marketplace->getSales().size());
+    statistics += "<br />Umsatz: " + m_marketplace->getOverallSumAsString();
 
-    ui_.statLabel->setText(statistics.c_str());
+    m_ui.statLabel->setText(statistics.c_str());
 }
diff --git a/src/gui/mainwindow.h b/src/gui/mainwindow.h
index 12f9689..1fba01a 100644
--- a/src/gui/mainwindow.h
+++ b/src/gui/mainwindow.h
@@ -16,7 +16,7 @@ class MainWindow : public QMainWindow
 
   public:
     MainWindow();
-    Marketplace* getMarketplace() { return marketplace_.get(); }
+    Marketplace* getMarketplace() { return m_marketplace.get(); }
 
   private slots:
     void onBasketViewSelectionChanged(const QItemSelection& selected,
@@ -49,8 +49,8 @@ class MainWindow : public QMainWindow
     void readGeometry();
     void updateStatLabel();
 
-    Ui::MainWindow ui_;
-    std::unique_ptr<Marketplace> marketplace_;
+    Ui::MainWindow m_ui;
+    std::unique_ptr<Marketplace> m_marketplace;
 };
 
 #endif
diff --git a/src/gui/pricedialog.cpp b/src/gui/pricedialog.cpp
index 93a7223..46546c8 100644
--- a/src/gui/pricedialog.cpp
+++ b/src/gui/pricedialog.cpp
@@ -6,31 +6,31 @@
 
 PriceDialog::PriceDialog(QWidget* parent, bool forceDesc, Qt::WindowFlags f) : QDialog(parent, f)
 {
-    forceDesc_ = forceDesc;
-    ui_.setupUi(this);
-    ui_.priceSpinBox->setFocus();
+    m_forceDesc = forceDesc;
+    m_ui.setupUi(this);
+    m_ui.priceSpinBox->setFocus();
 }
 
-int PriceDialog::getPrice() const { return static_cast<int>(ui_.priceSpinBox->value() * 100); }
+int PriceDialog::getPrice() const { return static_cast<int>(m_ui.priceSpinBox->value() * 100); }
 
-std::string PriceDialog::getDescription() const { return ui_.descEdit->text().toStdString(); }
+std::string PriceDialog::getDescription() const { return m_ui.descEdit->text().toStdString(); }
 
 void PriceDialog::accept()
 {
-    if (static_cast<int>(std::round(ui_.priceSpinBox->value() * 100.0L)) % 50 != 0) {
+    if (static_cast<int>(std::round(m_ui.priceSpinBox->value() * 100.0L)) % 50 != 0) {
         QMessageBox(QMessageBox::Icon::Warning, "Falsche Preiseingabe",
                     "Es sind nur 0,50 Cent-Schritte erlaubt.", QMessageBox::StandardButton::Ok,
                     this)
             .exec();
-    } else if (forceDesc_ && ui_.descEdit->text().trimmed().isEmpty()) {
+    } else if (m_forceDesc && m_ui.descEdit->text().trimmed().isEmpty()) {
         QMessageBox(QMessageBox::Icon::Warning, "Artikelbeschreibung fehlt",
                     "Da Sie auf das Sonderkonto buchen ist eine Artikelbeschreibung erforderlich.",
                     QMessageBox::StandardButton::Ok, this)
             .exec();
-        ui_.descEdit->setFocus();
+        m_ui.descEdit->setFocus();
     } else {
         QDialog::accept();
     }
 }
 
-void PriceDialog::setForceDesc(bool force) { forceDesc_ = force; }
\ No newline at end of file
+void PriceDialog::setForceDesc(bool force) { m_forceDesc = force; }
\ No newline at end of file
diff --git a/src/gui/pricedialog.h b/src/gui/pricedialog.h
index 229d2f3..5d9cbdf 100644
--- a/src/gui/pricedialog.h
+++ b/src/gui/pricedialog.h
@@ -19,8 +19,8 @@ class PriceDialog : public QDialog
   private:
     void on_model_duplicateSellerNo(const QString& message);
     virtual void accept() override;
-    Ui::PriceDialog ui_;
-    bool forceDesc_;
+    Ui::PriceDialog m_ui;
+    bool m_forceDesc;
 };
 
 #endif
\ No newline at end of file
diff --git a/src/gui/reportdialog.cpp b/src/gui/reportdialog.cpp
index 4ec1f8b..decf8d2 100644
--- a/src/gui/reportdialog.cpp
+++ b/src/gui/reportdialog.cpp
@@ -19,20 +19,20 @@ namespace fs = std::filesystem;
 
 ReportDialog::ReportDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(parent, f)
 {
-    ui_.setupUi(this);
-    market_ = dynamic_cast<MainWindow *>(parent)->getMarketplace();
-    model_ = std::make_unique<ReportModel>(market_, ui_.reportView);
-    ui_.reportView->setModel(model_.get());
-    ui_.reportView->hideColumn(0);
-    ui_.reportView->setRowHidden(0, true); // hide the special "Sonderkonto" user
+    m_ui.setupUi(this);
+    m_market = dynamic_cast<MainWindow *>(parent)->getMarketplace();
+    m_model = std::make_unique<ReportModel>(m_market, m_ui.reportView);
+    m_ui.reportView->setModel(m_model.get());
+    m_ui.reportView->hideColumn(0);
+    m_ui.reportView->setRowHidden(0, true); // hide the special "Sonderkonto" user
 
-    connect(ui_.exportCsvButton, &QPushButton::clicked, this,
+    connect(m_ui.exportCsvButton, &QPushButton::clicked, this,
             &ReportDialog::onExportCsvButtonClicked);
-    connect(ui_.printReportButton, &QPushButton::clicked, this,
+    connect(m_ui.printReportButton, &QPushButton::clicked, this,
             &ReportDialog::onPrintReportButtonClicked);
-    connect(ui_.printSellerReceiptButton, &QPushButton::clicked, this,
+    connect(m_ui.printSellerReceiptButton, &QPushButton::clicked, this,
             &ReportDialog::onPrintSellerReceiptButtonClicked);
-    connect(ui_.reportView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
+    connect(m_ui.reportView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
             &ReportDialog::onReportViewSelectionChanged);
 }
 
@@ -54,7 +54,7 @@ void ReportDialog::onExportCsvButtonClicked()
     fs::path filePath(filename.toStdString());
 #endif
 
-    market_->exportReportToCSV(filePath, feeInPercent, maxFeeInEuro);
+    m_market->exportReportToCSV(filePath, feeInPercent, maxFeeInEuro);
 }
 
 void ReportDialog::onPrintReportButtonClicked()
@@ -76,7 +76,7 @@ void ReportDialog::onPrintReportButtonClicked()
     int height = printer.height();
     int width = printer.width();
     const double ENTRIES_PER_PAGE = 51;
-    const auto &sellers = market_->getSellers();
+    const auto &sellers = m_market->getSellers();
     unsigned int numPages = std::ceil(sellers.size() / ENTRIES_PER_PAGE);
 
     painter.begin(&printer);
@@ -126,7 +126,7 @@ void ReportDialog::onPrintReportButtonClicked()
     }
 
     // pieces booked on the special account "Sonderkonto"
-    const auto specialSeller = market_->findSellerWithSellerNo(0);
+    const auto specialSeller = m_market->findSellerWithSellerNo(0);
     if (specialSeller && specialSeller->numArticlesSold() > 0) {
         printer.newPage();
         painter.setFont(QFont("Arial", 16, QFont::Bold));
@@ -163,8 +163,8 @@ void ReportDialog::onPrintReportButtonClicked()
                      "Auswertung Kindersachenmarkt");
     painter.setFont(fixedFont);
     QString content("Gesamtstatistik\n===============\n\n");
-    int numArticlesOffered = market_->getNumArticlesOffered();
-    int numArticlesSold = market_->getNumArticlesSold();
+    int numArticlesOffered = m_market->getNumArticlesOffered();
+    int numArticlesSold = m_market->getNumArticlesSold();
     double percentArticlesSold =
         (static_cast<double>(numArticlesSold) / static_cast<double>(numArticlesOffered)) * 100;
     content += QString("Registrierte Verkäufer: %1\n").arg(sellers.size() - 1, 6);
@@ -172,14 +172,14 @@ void ReportDialog::onPrintReportButtonClicked()
     content += QString("Verkaufte Artikel:      %1 (%L2 %)\n")
                    .arg(numArticlesSold, 6)
                    .arg(percentArticlesSold, 0, 'f', 2);
-    content += QString("Anzahl Kunden:          %1\n\n").arg(market_->getSales().size(), 6);
-    content += QString("Gesamtumsatz:     %1\n").arg(market_->getOverallSumAsString().c_str(), 10);
+    content += QString("Anzahl Kunden:          %1\n\n").arg(m_market->getSales().size(), 6);
+    content += QString("Gesamtumsatz:     %1\n").arg(m_market->getOverallSumAsString().c_str(), 10);
     content +=
         QString("Ausgezahlt:       %1\n")
-            .arg(market_->getOverallPaymentAsString(feeInPercent, maxFeeInEuro * 100).c_str(), 10);
+            .arg(m_market->getOverallPaymentAsString(feeInPercent, maxFeeInEuro * 100).c_str(), 10);
     content +=
         QString("Verbleibend:      %1\n\n")
-            .arg(market_->getOverallRevenueAsString(feeInPercent, maxFeeInEuro * 100).c_str(), 10);
+            .arg(m_market->getOverallRevenueAsString(feeInPercent, maxFeeInEuro * 100).c_str(), 10);
     content += QString("(Einbehaltener Prozentsatz:    %1 %)\n").arg(feeInPercent, 3);
     content += QString("(Maximal einbehaltener Betrag: %1 €)\n").arg(maxFeeInEuro, 3);
 
@@ -196,12 +196,12 @@ void ReportDialog::onPrintSellerReceiptButtonClicked()
     QString posPrinterDevice = settings.value("global/posPrinterDevice", "").toString();
     QString posPrinterEndpoint = settings.value("global/posPrinterEndpoint", "").toString();
 
-    auto selModel = ui_.reportView->selectionModel();
+    auto selModel = m_ui.reportView->selectionModel();
     if (selModel->hasSelection() == false)
         return;
 
     auto indexes = selModel->selectedRows();
-    auto &seller = market_->getSellers().at(indexes[0].row());
+    auto &seller = m_market->getSellers().at(indexes[0].row());
 
     auto printerDevice =
         convertToPosPrinterDevice(posPrinterDevice.toStdString(), posPrinterEndpoint.toStdString());
@@ -224,8 +224,8 @@ void ReportDialog::onReportViewSelectionChanged(const QItemSelection &selected,
                                                 [[maybe_unused]] const QItemSelection &deselected)
 {
     if (selected.size() > 0) {
-        ui_.printSellerReceiptButton->setEnabled(true);
+        m_ui.printSellerReceiptButton->setEnabled(true);
     } else {
-        ui_.printSellerReceiptButton->setEnabled(false);
+        m_ui.printSellerReceiptButton->setEnabled(false);
     }
 }
diff --git a/src/gui/reportdialog.h b/src/gui/reportdialog.h
index 18e1802..33713d8 100644
--- a/src/gui/reportdialog.h
+++ b/src/gui/reportdialog.h
@@ -25,9 +25,9 @@ class ReportDialog : public QDialog
                                       const QItemSelection& deselected);
 
   private:
-    Ui::ReportDialog ui_;
-    Marketplace* market_;
-    std::unique_ptr<ReportModel> model_;
+    Ui::ReportDialog m_ui;
+    Marketplace* m_market;
+    std::unique_ptr<ReportModel> m_model;
 };
 
 #endif
diff --git a/src/gui/reportmodel.cpp b/src/gui/reportmodel.cpp
index 65d386f..20acadd 100644
--- a/src/gui/reportmodel.cpp
+++ b/src/gui/reportmodel.cpp
@@ -5,16 +5,16 @@
 #include <QSettings>
 
 ReportModel::ReportModel(Marketplace* market, QObject* parent)
-    : QAbstractTableModel(parent), market_(market)
+    : QAbstractTableModel(parent), m_market(market)
 {
     QSettings settings;
-    feeInPercent_ = settings.value("global/feeInPercent").toInt();
-    maxFeeInCent_ = settings.value("global/maxFeeInEuro").toInt() * 100;
+    m_feeInPercent = settings.value("global/feeInPercent").toInt();
+    m_maxFeeInCent = settings.value("global/maxFeeInEuro").toInt() * 100;
 }
 
 int ReportModel::rowCount([[maybe_unused]] const QModelIndex& parent) const
 {
-    return static_cast<int>(market_->getSellers().size());
+    return static_cast<int>(m_market->getSellers().size());
 }
 
 int ReportModel::columnCount([[maybe_unused]] const QModelIndex& parent) const { return 7; }
@@ -52,10 +52,10 @@ QVariant ReportModel::data(const QModelIndex& index, int role) const
     if (role != Qt::DisplayRole)
         return QVariant();
 
-    if (market_->getSellers().size() == 0)
+    if (m_market->getSellers().size() == 0)
         return QVariant();
 
-    Seller* seller = market_->getSellers().at(index.row()).get();
+    Seller* seller = m_market->getSellers().at(index.row()).get();
 
     switch (index.column()) {
     case 0:
@@ -71,7 +71,7 @@ QVariant ReportModel::data(const QModelIndex& index, int role) const
     case 5:
         return seller->sumAsString().c_str();
     case 6:
-        return paymentAsString(seller->sumInCents(), feeInPercent_, maxFeeInCent_).c_str();
+        return paymentAsString(seller->sumInCents(), m_feeInPercent, m_maxFeeInCent).c_str();
     default:
         return "???";
     }
diff --git a/src/gui/reportmodel.h b/src/gui/reportmodel.h
index 36855da..1bb8d3c 100644
--- a/src/gui/reportmodel.h
+++ b/src/gui/reportmodel.h
@@ -15,9 +15,9 @@ class ReportModel : public QAbstractTableModel
     virtual QVariant headerData(int section, Qt::Orientation orientation, int role) const override;
 
   private:
-    Marketplace* market_;
-    int feeInPercent_{};
-    int maxFeeInCent_{};
+    Marketplace* m_market;
+    int m_feeInPercent{};
+    int m_maxFeeInCent{};
 };
 
 #endif
diff --git a/src/gui/salemodel.cpp b/src/gui/salemodel.cpp
index 93289e1..71dfae9 100644
--- a/src/gui/salemodel.cpp
+++ b/src/gui/salemodel.cpp
@@ -9,7 +9,7 @@
 
 SaleModel::SaleModel(Marketplace* market, QObject* parent) : QAbstractItemModel(parent)
 {
-    marketplace_ = market;
+    m_marketplace = market;
 }
 
 QModelIndex SaleModel::index(int row, int column, const QModelIndex& parent) const
@@ -18,7 +18,7 @@ QModelIndex SaleModel::index(int row, int column, const QModelIndex& parent) con
         return QModelIndex();
 
     if (!parent.isValid()) {
-        Sale* sale = marketplace_->getSales().at(row).get();
+        Sale* sale = m_marketplace->getSales().at(row).get();
         return createIndex(row, column, sale);
     } else if (!parent.parent().isValid()) {
         Sale* sale = static_cast<Sale*>(parent.internalPointer());
@@ -49,10 +49,10 @@ QModelIndex SaleModel::parent(const QModelIndex& index) const
     sale = dynamic_cast<Sale*>(ent);
 
     if (sale) {
-        if (sale == rootItem.get())
+        if (sale == m_rootItem.get())
             return QModelIndex();
         else {
-            return createIndex(-1, 0, rootItem.get());
+            return createIndex(-1, 0, m_rootItem.get());
         }
     } else {
         article = dynamic_cast<Article*>(ent);
@@ -132,7 +132,7 @@ int SaleModel::rowCount(const QModelIndex& parent) const
         return 0;
 
     if (!parent.isValid()) {
-        return marketplace_->getSales().size();
+        return m_marketplace->getSales().size();
     } else if (!parent.parent().isValid()) {
         Sale* sale = static_cast<Sale*>(parent.internalPointer());
         return sale->getArticles().size();
@@ -167,7 +167,7 @@ QVariant SaleModel::headerData(int section, Qt::Orientation orientation, int rol
 void SaleModel::onBasketDataChanged()
 {
     emit beginResetModel();
-    auto& sales = marketplace_->getSales();
+    auto& sales = m_marketplace->getSales();
     std::sort(sales.begin(), sales.end(), [](const auto& lhs, const auto& rhs) {
         return lhs->getTimestamp() > rhs->getTimestamp();
     });
@@ -179,11 +179,11 @@ bool SaleModel::removeRows(int row, int count, const QModelIndex& parent)
     if (!parent.isValid()) {
         // remove complete sale
         emit beginRemoveRows(parent, row, row + count - 1);
-        auto& sale = marketplace_->getSales().at(row);
+        auto& sale = m_marketplace->getSales().at(row);
         sale->setState(Sale::State::DELETE);
         std::for_each(sale->getArticles().begin(), sale->getArticles().end(),
                       [](auto& a) { a->setState(Article::State::DELETE); });
-        marketplace_->storeToDb();
+        m_marketplace->storeToDb();
         emit endRemoveRows();
 
     } else if (!parent.parent().isValid()) {
@@ -199,7 +199,7 @@ bool SaleModel::removeRows(int row, int count, const QModelIndex& parent)
             sale->setState(Sale::State::DELETE);
         }
         emit beginRemoveRows(parent.parent(), 0, 0);
-        marketplace_->storeToDb();
+        m_marketplace->storeToDb();
         emit endRemoveRows();
     }
 
diff --git a/src/gui/salemodel.h b/src/gui/salemodel.h
index 6675bd6..29a13bf 100644
--- a/src/gui/salemodel.h
+++ b/src/gui/salemodel.h
@@ -24,8 +24,8 @@ class SaleModel : public QAbstractItemModel
     void onBasketDataChanged();
 
   private:
-    Marketplace* marketplace_;
-    std::unique_ptr<Sale> rootItem{new Sale()};
+    Marketplace* m_marketplace;
+    std::unique_ptr<Sale> m_rootItem{new Sale()};
 };
 
 #endif
diff --git a/src/gui/sellerdialog.cpp b/src/gui/sellerdialog.cpp
index 9ecf63f..0b678fd 100644
--- a/src/gui/sellerdialog.cpp
+++ b/src/gui/sellerdialog.cpp
@@ -7,25 +7,25 @@
 
 SellerDialog::SellerDialog(QWidget* parent, Qt::WindowFlags f) : QDialog(parent, f)
 {
-    ui_.setupUi(this);
-    ui_.editButton->setVisible(false);
-    market_ = dynamic_cast<MainWindow*>(parent)->getMarketplace();
-    model_ = std::make_unique<SellerModel>(market_, ui_.tableView);
-    ui_.tableView->setModel(model_.get());
-    ui_.tableView->setColumnHidden(0, true); // hide the uuid
-    ui_.tableView->setRowHidden(0, true);    // hide the special "Sonderkonto" user
-    connect(ui_.newButton, &QPushButton::clicked, this, &SellerDialog::on_newButton_clicked);
-    connect(ui_.deleteButton, &QPushButton::clicked, this, &SellerDialog::on_deleteButton_clicked);
-    connect(model_.get(), &SellerModel::duplicateSellerNo, this,
+    m_ui.setupUi(this);
+    m_ui.editButton->setVisible(false);
+    m_market = dynamic_cast<MainWindow*>(parent)->getMarketplace();
+    m_model = std::make_unique<SellerModel>(m_market, m_ui.tableView);
+    m_ui.tableView->setModel(m_model.get());
+    m_ui.tableView->setColumnHidden(0, true); // hide the uuid
+    m_ui.tableView->setRowHidden(0, true);    // hide the special "Sonderkonto" user
+    connect(m_ui.newButton, &QPushButton::clicked, this, &SellerDialog::on_newButton_clicked);
+    connect(m_ui.deleteButton, &QPushButton::clicked, this, &SellerDialog::on_deleteButton_clicked);
+    connect(m_model.get(), &SellerModel::duplicateSellerNo, this,
             &SellerDialog::on_model_duplicateSellerNo);
-    connect(ui_.tableView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
+    connect(m_ui.tableView->selectionModel(), &QItemSelectionModel::selectionChanged, this,
             &SellerDialog::onSellerViewSelectionChanged);
 }
 
 void SellerDialog::on_newButton_clicked()
 {
     // Don't allow new seller if market has already started
-    if (market_->getSales().size() > 0) {
+    if (m_market->getSales().size() > 0) {
         QMessageBox(QMessageBox::Icon::Warning, "Hinweis",
                     "Da die Verkaufsphase schon begonnen hat (Artikel wurden bereits verkauft) "
                     "können Sie keine Verkäufer mehr hinzufügen.",
@@ -34,22 +34,22 @@ void SellerDialog::on_newButton_clicked()
         return;
     }
 
-    ui_.tableView->reset();
-    ui_.tableView->model()->insertRows(ui_.tableView->model()->rowCount(), 1);
-    ui_.tableView->scrollToBottom();
-    ui_.tableView->selectRow(ui_.tableView->model()->rowCount() - 1);
-    QModelIndex idx = ui_.tableView->model()->index(ui_.tableView->model()->rowCount() - 1, 2);
-    ui_.tableView->setCurrentIndex(idx);
-    ui_.tableView->edit(idx);
+    m_ui.tableView->reset();
+    m_ui.tableView->model()->insertRows(m_ui.tableView->model()->rowCount(), 1);
+    m_ui.tableView->scrollToBottom();
+    m_ui.tableView->selectRow(m_ui.tableView->model()->rowCount() - 1);
+    QModelIndex idx = m_ui.tableView->model()->index(m_ui.tableView->model()->rowCount() - 1, 2);
+    m_ui.tableView->setCurrentIndex(idx);
+    m_ui.tableView->edit(idx);
 }
 
 void SellerDialog::on_deleteButton_clicked()
 {
-    auto selModel = ui_.tableView->selectionModel();
+    auto selModel = m_ui.tableView->selectionModel();
     if (selModel->hasSelection() == false)
         return;
 
-    if (market_->getSales().size() > 0) {
+    if (m_market->getSales().size() > 0) {
         QMessageBox(QMessageBox::Icon::Warning, "Hinweis",
                     "Da die Verkaufsphase schon begonnen hat (Artikel wurden bereits verkauft) "
                     "können Sie keine Verkäufer mehr löschen.",
@@ -72,7 +72,7 @@ void SellerDialog::on_deleteButton_clicked()
 
     // Deleting the rows, beginning with the last one!
     for (auto iter = indexes.constEnd() - 1; iter >= indexes.constBegin(); --iter) {
-        ui_.tableView->model()->removeRow(iter->row());
+        m_ui.tableView->model()->removeRow(iter->row());
     }
 }
 
@@ -102,8 +102,8 @@ void SellerDialog::onSellerViewSelectionChanged(const QItemSelection& selected,
                                                 [[maybe_unused]] const QItemSelection& deselected)
 {
     if (selected.size() > 0) {
-        ui_.deleteButton->setEnabled(true);
+        m_ui.deleteButton->setEnabled(true);
     } else {
-        ui_.deleteButton->setEnabled(false);
+        m_ui.deleteButton->setEnabled(false);
     }
 }
\ No newline at end of file
diff --git a/src/gui/sellerdialog.h b/src/gui/sellerdialog.h
index 63e53fb..ea87d4d 100644
--- a/src/gui/sellerdialog.h
+++ b/src/gui/sellerdialog.h
@@ -26,9 +26,9 @@ class SellerDialog : public QDialog
     void on_deleteButton_clicked();
     void on_model_duplicateSellerNo(const QString& message);
     virtual void accept() override;
-    Ui::SellerDialog ui_;
-    Marketplace* market_;
-    std::unique_ptr<SellerModel> model_;
+    Ui::SellerDialog m_ui;
+    Marketplace* m_market;
+    std::unique_ptr<SellerModel> m_model;
 };
 
 #endif
\ No newline at end of file
diff --git a/src/gui/sellermodel.cpp b/src/gui/sellermodel.cpp
index 63b939e..a93f2ba 100644
--- a/src/gui/sellermodel.cpp
+++ b/src/gui/sellermodel.cpp
@@ -5,13 +5,13 @@
 #include <QMessageBox>
 
 SellerModel::SellerModel(Marketplace* market, QObject* parent)
-    : QAbstractTableModel(parent), marketplace_(market)
+    : QAbstractTableModel(parent), m_marketplace(market)
 {
 }
 
 int SellerModel::rowCount([[maybe_unused]] const QModelIndex& parent) const
 {
-    return marketplace_->getSellers().size();
+    return m_marketplace->getSellers().size();
 }
 
 int SellerModel::columnCount([[maybe_unused]] const QModelIndex& parent) const { return 5; }
@@ -21,10 +21,10 @@ QVariant SellerModel::data(const QModelIndex& index, int role) const
     if (role != Qt::DisplayRole)
         return QVariant();
 
-    if (marketplace_->getSellers().size() == 0)
+    if (m_marketplace->getSellers().size() == 0)
         return QVariant();
 
-    Seller* seller = marketplace_->getSellers().at(index.row()).get();
+    Seller* seller = m_marketplace->getSellers().at(index.row()).get();
 
     switch (index.column()) {
     case 0:
@@ -78,7 +78,7 @@ bool SellerModel::setData(const QModelIndex& index, const QVariant& value, int r
     if (role != Qt::EditRole)
         return false;
 
-    Seller* seller = marketplace_->getSellers().at(index.row()).get();
+    Seller* seller = m_marketplace->getSellers().at(index.row()).get();
 
     switch (index.column()) {
     case 0:
@@ -88,11 +88,11 @@ bool SellerModel::setData(const QModelIndex& index, const QVariant& value, int r
         if (value.toInt() < 0)
             return false;
         auto iter =
-            std::find_if(marketplace_->getSellers().begin(), marketplace_->getSellers().end(),
+            std::find_if(m_marketplace->getSellers().begin(), m_marketplace->getSellers().end(),
                          [&value](const std::unique_ptr<Seller>& s) {
                              return value.toInt() == s->getSellerNo();
                          });
-        if (iter != marketplace_->getSellers().end()) {
+        if (iter != m_marketplace->getSellers().end()) {
             emit duplicateSellerNo(
                 "Die Verkäufernummer muss eindeutig sein.\n(Möglicherweise wird die Nummer von "
                 "einem (ausgeblendeten) Eintrag, der zum Löschen vorgemerkt ist, verwendet.)");
@@ -123,8 +123,8 @@ bool SellerModel::insertRows(int row, int count, const QModelIndex& parent)
 {
     emit beginInsertRows(parent, row, row + count - 1);
     auto seller = std::make_unique<Seller>();
-    seller->setSellerNo(marketplace_->getNextSellerNo());
-    marketplace_->getSellers().push_back(std::move(seller));
+    seller->setSellerNo(m_marketplace->getNextSellerNo());
+    m_marketplace->getSellers().push_back(std::move(seller));
     emit endInsertRows();
 
     return true;
@@ -132,21 +132,21 @@ bool SellerModel::insertRows(int row, int count, const QModelIndex& parent)
 
 bool SellerModel::removeRows(int row, int count, const QModelIndex& parent)
 {
-    auto seller = marketplace_->getSellers().at(row).get();
+    auto seller = m_marketplace->getSellers().at(row).get();
     if (seller->getState() == Seller::State::NEW) {
         emit beginRemoveRows(parent, row, row + count - 1);
-        marketplace_->getSellers().erase(
-            std::remove_if(marketplace_->getSellers().begin(), marketplace_->getSellers().end(),
+        m_marketplace->getSellers().erase(
+            std::remove_if(m_marketplace->getSellers().begin(), m_marketplace->getSellers().end(),
                            [&seller](const std::unique_ptr<Seller>& a) {
                                return a->getId() == seller->getId();
                            }),
-            marketplace_->getSellers().end());
+            m_marketplace->getSellers().end());
         emit endRemoveRows();
         return true;
     } else {
         emit beginRemoveRows(parent, row, row + count - 1);
         seller->setState(Seller::State::DELETE);
-        marketplace_->storeToDb(true);
+        m_marketplace->storeToDb(true);
         emit endRemoveRows();
         return true;
     }
diff --git a/src/gui/sellermodel.h b/src/gui/sellermodel.h
index 32b6b7d..52b99a7 100644
--- a/src/gui/sellermodel.h
+++ b/src/gui/sellermodel.h
@@ -9,23 +9,23 @@ class SellerModel : public QAbstractTableModel
 {
     Q_OBJECT
 
-  public:
-    explicit SellerModel(Marketplace* market, QObject* parent = nullptr);
-    virtual int rowCount(const QModelIndex& parent = QModelIndex()) const override;
-    virtual int columnCount(const QModelIndex& parent = QModelIndex()) const override;
-    virtual QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
+public:
+    explicit SellerModel(Marketplace *market, QObject *parent = nullptr);
+    virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    virtual int columnCount(const QModelIndex &parent = QModelIndex()) const override;
+    virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     virtual QVariant headerData(int section, Qt::Orientation orientation, int role) const override;
-    virtual Qt::ItemFlags flags(const QModelIndex& index) const override;
-    virtual bool setData(const QModelIndex& index, const QVariant& value,
+    virtual Qt::ItemFlags flags(const QModelIndex &index) const override;
+    virtual bool setData(const QModelIndex &index, const QVariant &value,
                          int role = Qt::EditRole) override;
-    virtual bool insertRows(int row, int count, const QModelIndex& parent = QModelIndex()) override;
-    virtual bool removeRows(int row, int count, const QModelIndex& parent = QModelIndex()) override;
+    virtual bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex()) override;
+    virtual bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex()) override;
 
-  signals:
-    void duplicateSellerNo(const QString& message);
+signals:
+    void duplicateSellerNo(const QString &message);
 
-  private:
-    Marketplace* marketplace_;
+private:
+    Marketplace *m_marketplace;
 };
 
 #endif
diff --git a/src/gui/settingsdialog.cpp b/src/gui/settingsdialog.cpp
index c4289e7..7dfee89 100644
--- a/src/gui/settingsdialog.cpp
+++ b/src/gui/settingsdialog.cpp
@@ -15,7 +15,7 @@
 
 SettingsDialog::SettingsDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(parent, f)
 {
-    ui_.setupUi(this);
+    m_ui.setupUi(this);
 
     QSettings settings{};
     int cashPointNo = settings.value("global/cashPointNo").toInt();
@@ -26,25 +26,25 @@ SettingsDialog::SettingsDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(par
     int maxFeeInEuro = settings.value("global/maxFeeInEuro").toInt();
 
     if (parent)
-        market_ = dynamic_cast<MainWindow *>(parent)->getMarketplace();
+        m_market = dynamic_cast<MainWindow *>(parent)->getMarketplace();
 
-    ui_.cashPointNoSpinBox->setValue(cashPointNo);
-    ui_.communeEdit->setText(commune);
-    ui_.posPrinterDeviceEdit->setText(posPrinterDevice);
-    ui_.posPrinterEndpointEdit->setText(posPrinterEndpoint);
-    ui_.feePercentSpinBox->setValue(feeInPercent);
-    ui_.maxFeeSpinBox->setValue(maxFeeInEuro);
+    m_ui.cashPointNoSpinBox->setValue(cashPointNo);
+    m_ui.communeEdit->setText(commune);
+    m_ui.posPrinterDeviceEdit->setText(posPrinterDevice);
+    m_ui.posPrinterEndpointEdit->setText(posPrinterEndpoint);
+    m_ui.feePercentSpinBox->setValue(feeInPercent);
+    m_ui.maxFeeSpinBox->setValue(maxFeeInEuro);
 
-    connect(ui_.testPosPrinterButton, &QPushButton::clicked, this, [this]() {
+    connect(m_ui.testPosPrinterButton, &QPushButton::clicked, this, [this]() {
         using namespace std::string_literals;
         try {
-            if (ui_.posPrinterDeviceEdit->text().isEmpty()) {
+            if (m_ui.posPrinterDeviceEdit->text().isEmpty()) {
                 PosPrinter printer;
                 printer.printTest();
             } else {
-                std::string posPrinterDeviceString = ui_.posPrinterDeviceEdit->text().toStdString();
+                std::string posPrinterDeviceString = m_ui.posPrinterDeviceEdit->text().toStdString();
                 std::string posPrinterEndpointString =
-                    ui_.posPrinterEndpointEdit->text().toStdString();
+                    m_ui.posPrinterEndpointEdit->text().toStdString();
 
                 try {
                     auto printerDevice =
@@ -80,17 +80,17 @@ void SettingsDialog::accept()
     QSettings settings;
 
     int oldCashPointNo = settings.value("global/cashPointNo").toInt();
-    int newCashPointNo = ui_.cashPointNoSpinBox->value();
+    int newCashPointNo = m_ui.cashPointNoSpinBox->value();
 
-    settings.setValue("global/commune", ui_.communeEdit->text().trimmed());
-    settings.setValue("global/posPrinterDevice", ui_.posPrinterDeviceEdit->text().trimmed());
-    settings.setValue("global/posPrinterEndpoint", ui_.posPrinterEndpointEdit->text().trimmed());
-    settings.setValue("global/feeInPercent", ui_.feePercentSpinBox->value());
-    settings.setValue("global/maxFeeInEuro", ui_.maxFeeSpinBox->value());
+    settings.setValue("global/commune", m_ui.communeEdit->text().trimmed());
+    settings.setValue("global/posPrinterDevice", m_ui.posPrinterDeviceEdit->text().trimmed());
+    settings.setValue("global/posPrinterEndpoint", m_ui.posPrinterEndpointEdit->text().trimmed());
+    settings.setValue("global/feeInPercent", m_ui.feePercentSpinBox->value());
+    settings.setValue("global/maxFeeInEuro", m_ui.maxFeeSpinBox->value());
 
     if (oldCashPointNo != newCashPointNo) {
         int result{0};
-        if (market_ && market_->getSales().size() > 0) {
+        if (m_market && m_market->getSales().size() > 0) {
             result = QMessageBox(QMessageBox::Icon::Question, "Sind Sie sicher?",
                                  "Möchten Sie die Kassen-Nr wirklich ändern? Diese muss über alle "
                                  "Installationen hinweg eindeutig sein.",
@@ -112,7 +112,7 @@ void SettingsDialog::accept()
                 QDialog::accept();
                 return;
             }
-            settings.setValue("global/cashPointNo", ui_.cashPointNoSpinBox->value());
+            settings.setValue("global/cashPointNo", m_ui.cashPointNoSpinBox->value());
         }
     }
 
diff --git a/src/gui/settingsdialog.h b/src/gui/settingsdialog.h
index a1a7026..541cc80 100644
--- a/src/gui/settingsdialog.h
+++ b/src/gui/settingsdialog.h
@@ -19,8 +19,8 @@ class SettingsDialog : public QDialog
     void accept() override;
 
   private:
-    Ui::SettingsDialog ui_;
-    Marketplace* market_{};
+    Ui::SettingsDialog m_ui;
+    Marketplace* m_market{};
 };
 
 #endif