diff --git a/src/headwordsmodel.cc b/src/headwordsmodel.cc
index c7a999f3..5add84a8 100644
--- a/src/headwordsmodel.cc
+++ b/src/headwordsmodel.cc
@@ -2,7 +2,7 @@
 #include "wstring_qt.hh"
 
 HeadwordListModel::HeadwordListModel( QObject * parent ) :
-  QAbstractListModel( parent ), filtering( false ), totalSize(0), index( 0 ),ptr( 0 )
+  QAbstractListModel( parent ), filtering( false ), totalSize(0), index( 0 ),ptr( nullptr )
 {
 }
 
@@ -49,7 +49,7 @@ void HeadwordListModel::setFilter( QRegularExpression reg )
 void HeadwordListModel::addMatches( QStringList matches)
 {
   QStringList filtered;
-  for ( auto & w : matches ) {
+  for ( auto const & w : matches ) {
     if ( !words.contains( w ) ) {
       filtered << w;
     }
diff --git a/src/ui/dictheadwords.cc b/src/ui/dictheadwords.cc
index 931cbd50..b112586e 100644
--- a/src/ui/dictheadwords.cc
+++ b/src/ui/dictheadwords.cc
@@ -201,7 +201,7 @@ void DictHeadwords::filterChangedInternal()
     QTimer::singleShot( 100, this, &DictHeadwords::filterChanged );
 }
 
-QRegularExpression DictHeadwords::getFilterRegex(  )
+QRegularExpression DictHeadwords::getFilterRegex(  ) const
 {
   const QRegExp::PatternSyntax syntax =
     static_cast< QRegExp::PatternSyntax >(ui.searchModeCombo->itemData(
@@ -368,8 +368,7 @@ void DictHeadwords::saveHeadersToFile()
 
   QStringList filtered;
 
-  const QRegularExpression regExp = getFilterRegex();
-  if(regExp.isValid() && !regExp.pattern().isEmpty()){
+  if ( const QRegularExpression regExp = getFilterRegex(); regExp.isValid() && !regExp.pattern().isEmpty() ) {
     filtered = sortedWords.filter( regExp );
   }
   else{
diff --git a/src/ui/dictheadwords.hh b/src/ui/dictheadwords.hh
index 5bc1a26e..53022314 100644
--- a/src/ui/dictheadwords.hh
+++ b/src/ui/dictheadwords.hh
@@ -48,7 +48,7 @@ private:
 private slots:
   void savePos();
   void filterChangedInternal();
-  QRegularExpression getFilterRegex();
+  QRegularExpression getFilterRegex() const;
   void filterChanged();
   void exportButtonClicked();
   void okButtonClicked();