diff --git a/src/qt/sendcoinsdialog.h b/src/qt/sendcoinsdialog.h
--- a/src/qt/sendcoinsdialog.h
+++ b/src/qt/sendcoinsdialog.h
@@ -31,7 +31,7 @@
 
 public:
     explicit SendCoinsDialog(const PlatformStyle *platformStyle,
-                             QWidget *parent = 0);
+                             QWidget *parent = nullptr);
     ~SendCoinsDialog();
 
     void setClientModel(ClientModel *clientModel);
@@ -116,7 +116,7 @@
 public:
     SendConfirmationDialog(const QString &title, const QString &text,
                            int secDelay = SEND_CONFIRM_DELAY,
-                           QWidget *parent = 0);
+                           QWidget *parent = nullptr);
     int exec();
 
 private Q_SLOTS:
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -30,8 +30,8 @@
 
 SendCoinsDialog::SendCoinsDialog(const PlatformStyle *_platformStyle,
                                  QWidget *parent)
-    : QDialog(parent), ui(new Ui::SendCoinsDialog), clientModel(0), model(0),
-      fNewRecipientAllowed(true), fFeeMinimized(true),
+    : QDialog(parent), ui(new Ui::SendCoinsDialog), clientModel(nullptr),
+      model(nullptr), fNewRecipientAllowed(true), fFeeMinimized(true),
       platformStyle(_platformStyle) {
     ui->setupUi(this);
 
@@ -477,7 +477,7 @@
 }
 
 void SendCoinsDialog::setAddress(const QString &address) {
-    SendCoinsEntry *entry = 0;
+    SendCoinsEntry *entry = nullptr;
     // Replace the first entry if it is still unused
     if (ui->entries->count() == 1) {
         SendCoinsEntry *first =
@@ -498,7 +498,7 @@
         return;
     }
 
-    SendCoinsEntry *entry = 0;
+    SendCoinsEntry *entry = nullptr;
     // Replace the first entry if it is still unused
     if (ui->entries->count() == 1) {
         SendCoinsEntry *first =
diff --git a/src/qt/sendcoinsentry.h b/src/qt/sendcoinsentry.h
--- a/src/qt/sendcoinsentry.h
+++ b/src/qt/sendcoinsentry.h
@@ -26,7 +26,7 @@
 
 public:
     explicit SendCoinsEntry(const PlatformStyle *platformStyle,
-                            QWidget *parent = 0);
+                            QWidget *parent = nullptr);
     ~SendCoinsEntry();
 
     void setModel(WalletModel *model);
diff --git a/src/qt/sendcoinsentry.cpp b/src/qt/sendcoinsentry.cpp
--- a/src/qt/sendcoinsentry.cpp
+++ b/src/qt/sendcoinsentry.cpp
@@ -18,7 +18,7 @@
 
 SendCoinsEntry::SendCoinsEntry(const PlatformStyle *_platformStyle,
                                QWidget *parent)
-    : QStackedWidget(parent), ui(new Ui::SendCoinsEntry), model(0),
+    : QStackedWidget(parent), ui(new Ui::SendCoinsEntry), model(nullptr),
       platformStyle(_platformStyle) {
     ui->setupUi(this);
 
diff --git a/src/qt/walletframe.h b/src/qt/walletframe.h
--- a/src/qt/walletframe.h
+++ b/src/qt/walletframe.h
@@ -31,7 +31,7 @@
 
 public:
     explicit WalletFrame(const PlatformStyle *platformStyle,
-                         BitcoinGUI *_gui = 0);
+                         BitcoinGUI *_gui = nullptr);
     ~WalletFrame();
 
     void setClientModel(ClientModel *clientModel);
diff --git a/src/qt/walletview.h b/src/qt/walletview.h
--- a/src/qt/walletview.h
+++ b/src/qt/walletview.h
@@ -36,7 +36,7 @@
     Q_OBJECT
 
 public:
-    explicit WalletView(const PlatformStyle *platformStyle, QWidget *parent);
+    WalletView(const PlatformStyle *platformStyle, QWidget *parent);
     ~WalletView();
 
     void setBitcoinGUI(BitcoinGUI *gui);
diff --git a/src/qt/walletview.cpp b/src/qt/walletview.cpp
--- a/src/qt/walletview.cpp
+++ b/src/qt/walletview.cpp
@@ -30,7 +30,7 @@
 #include <QVBoxLayout>
 
 WalletView::WalletView(const PlatformStyle *_platformStyle, QWidget *parent)
-    : QStackedWidget(parent), clientModel(0), walletModel(0),
+    : QStackedWidget(parent), clientModel(nullptr), walletModel(nullptr),
       platformStyle(_platformStyle) {
     // Create tabs
     overviewPage = new OverviewPage(platformStyle);