diff --git a/src/Mod/Spreadsheet/App/Cell.cpp b/src/Mod/Spreadsheet/App/Cell.cpp
index f4414866a1..a4ab7cb35c 100644
--- a/src/Mod/Spreadsheet/App/Cell.cpp
+++ b/src/Mod/Spreadsheet/App/Cell.cpp
@@ -706,15 +706,15 @@ void Cell::moveAbsolute(CellAddress newAddress)
 
 void Cell::restore(Base::XMLReader &reader, bool checkAlias)
 {
-    const char* style = reader.hasAttribute("style") ? reader.getAttribute("style") : 0;
-    const char* alignment = reader.hasAttribute("alignment") ? reader.getAttribute("alignment") : 0;
+    const char* style = reader.hasAttribute("style") ? reader.getAttribute("style") : nullptr;
+    const char* alignment = reader.hasAttribute("alignment") ? reader.getAttribute("alignment") : nullptr;
     const char* content = reader.hasAttribute("content") ? reader.getAttribute("content") : "";
-    const char* foregroundColor = reader.hasAttribute("foregroundColor") ? reader.getAttribute("foregroundColor") : 0;
-    const char* backgroundColor = reader.hasAttribute("backgroundColor") ? reader.getAttribute("backgroundColor") : 0;
-    const char* displayUnit = reader.hasAttribute("displayUnit") ? reader.getAttribute("displayUnit") : 0;
-    const char* alias = reader.hasAttribute("alias") ? reader.getAttribute("alias") : 0;
-    const char* rowSpan = reader.hasAttribute("rowSpan") ? reader.getAttribute("rowSpan") : 0;
-    const char* colSpan = reader.hasAttribute("colSpan") ? reader.getAttribute("colSpan") : 0;
+    const char* foregroundColor = reader.hasAttribute("foregroundColor") ? reader.getAttribute("foregroundColor") : nullptr;
+    const char* backgroundColor = reader.hasAttribute("backgroundColor") ? reader.getAttribute("backgroundColor") : nullptr;
+    const char* displayUnit = reader.hasAttribute("displayUnit") ? reader.getAttribute("displayUnit") : nullptr;
+    const char* alias = reader.hasAttribute("alias") ? reader.getAttribute("alias") : nullptr;
+    const char* rowSpan = reader.hasAttribute("rowSpan") ? reader.getAttribute("rowSpan") : nullptr;
+    const char* colSpan = reader.hasAttribute("colSpan") ? reader.getAttribute("colSpan") : nullptr;
 
     // Don't trigger multiple updates below; wait until everything is loaded by calling unfreeze() below.
     PropertySheet::AtomicPropertyChange signaller(*owner);
@@ -1001,7 +1001,7 @@ App::Color Cell::decodeColor(const std::string & color, const App::Color & defau
 
         if (color[0] != '#')
             return defaultColor;
-        unsigned int value = strtoul(color.c_str() + 1, 0, 16);
+        unsigned int value = strtoul(color.c_str() + 1, nullptr, 16);
 
         if (color.size() == 7)
             value = (value << 8) | 0xff;
diff --git a/src/Mod/Spreadsheet/App/PropertyColumnWidths.cpp b/src/Mod/Spreadsheet/App/PropertyColumnWidths.cpp
index 4814564f4e..e6cce19eca 100644
--- a/src/Mod/Spreadsheet/App/PropertyColumnWidths.cpp
+++ b/src/Mod/Spreadsheet/App/PropertyColumnWidths.cpp
@@ -132,8 +132,8 @@ void PropertyColumnWidths::Restore(Base::XMLReader &reader)
     Cnt = reader.hasAttribute("Count") ? reader.getAttributeAsInteger("Count") : 0;
     for (int i = 0; i < Cnt; i++) {
         reader.readElement("Column");
-        const char* name = reader.hasAttribute("name") ? reader.getAttribute("name") : 0;
-        const char * width = reader.hasAttribute("width") ? reader.getAttribute("width") : 0;
+        const char* name = reader.hasAttribute("name") ? reader.getAttribute("name") : nullptr;
+        const char * width = reader.hasAttribute("width") ? reader.getAttribute("width") : nullptr;
 
         try {
             if (name && width) {
diff --git a/src/Mod/Spreadsheet/App/PropertyColumnWidthsPyImp.cpp b/src/Mod/Spreadsheet/App/PropertyColumnWidthsPyImp.cpp
index ec748df246..53f97d0a76 100644
--- a/src/Mod/Spreadsheet/App/PropertyColumnWidthsPyImp.cpp
+++ b/src/Mod/Spreadsheet/App/PropertyColumnWidthsPyImp.cpp
@@ -51,7 +51,7 @@ int PropertyColumnWidthsPy::PyInit(PyObject* /*args*/, PyObject* /*kwd*/)
 
 PyObject *PropertyColumnWidthsPy::getCustomAttributes(const char* /*attr*/) const
 {
-    return 0;
+    return nullptr;
 }
 
 int PropertyColumnWidthsPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
diff --git a/src/Mod/Spreadsheet/App/PropertyRowHeights.cpp b/src/Mod/Spreadsheet/App/PropertyRowHeights.cpp
index d7d4e5945e..d2278ee5a8 100644
--- a/src/Mod/Spreadsheet/App/PropertyRowHeights.cpp
+++ b/src/Mod/Spreadsheet/App/PropertyRowHeights.cpp
@@ -126,8 +126,8 @@ void PropertyRowHeights::Restore(Base::XMLReader &reader)
     Cnt = reader.hasAttribute("Count") ? reader.getAttributeAsInteger("Count") : 0;
     for (int i = 0; i < Cnt; i++) {
         reader.readElement("Row");
-        const char* name = reader.hasAttribute("name") ? reader.getAttribute("name") : 0;
-        const char * height = reader.hasAttribute("height") ? reader.getAttribute("height") : 0;
+        const char* name = reader.hasAttribute("name") ? reader.getAttribute("name") : nullptr;
+        const char * height = reader.hasAttribute("height") ? reader.getAttribute("height") : nullptr;
 
         try {
             if (name && height) {
diff --git a/src/Mod/Spreadsheet/App/PropertyRowHeightsPyImp.cpp b/src/Mod/Spreadsheet/App/PropertyRowHeightsPyImp.cpp
index 99a2efac06..80e7c06b87 100644
--- a/src/Mod/Spreadsheet/App/PropertyRowHeightsPyImp.cpp
+++ b/src/Mod/Spreadsheet/App/PropertyRowHeightsPyImp.cpp
@@ -51,7 +51,7 @@ int PropertyRowHeightsPy::PyInit(PyObject* /*args*/, PyObject* /*kwd*/)
 
 PyObject *PropertyRowHeightsPy::getCustomAttributes(const char* /*attr*/) const
 {
-    return 0;
+    return nullptr;
 }
 
 int PropertyRowHeightsPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
diff --git a/src/Mod/Spreadsheet/App/PropertySheet.cpp b/src/Mod/Spreadsheet/App/PropertySheet.cpp
index d224a5a2b2..b865a1a38b 100644
--- a/src/Mod/Spreadsheet/App/PropertySheet.cpp
+++ b/src/Mod/Spreadsheet/App/PropertySheet.cpp
@@ -86,7 +86,7 @@ Cell *PropertySheet::getValue(CellAddress key)
     std::map<CellAddress, Cell*>::const_iterator i = data.find(key);
 
     if (i == data.end())
-        return 0;
+        return nullptr;
     else
         return i->second;
 }
@@ -96,7 +96,7 @@ const Cell *PropertySheet::getValue(CellAddress key) const
     std::map<CellAddress, Cell*>::const_iterator i = data.find(key);
 
     if (i == data.end())
-        return 0;
+        return nullptr;
     else
         return i->second;
 }
@@ -108,7 +108,7 @@ Cell * PropertySheet::getValueFromAlias(const std::string &alias)
     if (it != revAliasProp.end())
         return getValue(it->second);
     else
-        return 0;
+        return nullptr;
 }
 
 const Cell * PropertySheet::getValueFromAlias(const std::string &alias) const
@@ -118,7 +118,7 @@ const Cell * PropertySheet::getValueFromAlias(const std::string &alias) const
     if (it != revAliasProp.end())
         return getValue(it->second);
     else
-        return 0;
+        return nullptr;
 }
 
 bool PropertySheet::isValidAlias(const std::string &candidate)
@@ -127,7 +127,7 @@ bool PropertySheet::isValidAlias(const std::string &candidate)
     boost::cmatch cm;
 
     /* Check if it is used before */
-    if (getValueFromAlias(candidate) != 0)
+    if (getValueFromAlias(candidate) != nullptr)
         return false;
 
     /* Check to make sure it doesn't clash with a predefined unit */
@@ -517,7 +517,7 @@ Cell * PropertySheet::cellAt(CellAddress address)
     std::map<CellAddress, Cell*>::const_iterator i = data.find(address);
 
     if (i == data.end())
-        return 0;
+        return nullptr;
     else
         return i->second;
 }
@@ -537,7 +537,7 @@ const Cell * PropertySheet::cellAt(CellAddress address) const
     std::map<CellAddress, Cell*>::const_iterator i = data.find(address);
 
     if (i == data.end())
-        return 0;
+        return nullptr;
     else
         return i->second;
 }
@@ -566,14 +566,14 @@ Cell * PropertySheet::nonNullCellAt(CellAddress address)
 void PropertySheet::setContent(CellAddress address, const char *value)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setContent(value);
 }
 
 void PropertySheet::setAlignment(CellAddress address, int _alignment)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     if (cell->address != address) return; //Reject alignment change for merged cell except top-left one
     cell->setAlignment(_alignment);
 }
@@ -581,28 +581,28 @@ void PropertySheet::setAlignment(CellAddress address, int _alignment)
 void PropertySheet::setStyle(CellAddress address, const std::set<std::string> &_style)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setStyle(_style);
 }
 
 void PropertySheet::setForeground(CellAddress address, const App::Color &color)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setForeground(color);
 }
 
 void PropertySheet::setBackground(CellAddress address, const App::Color &color)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setBackground(color);
 }
 
 void PropertySheet::setDisplayUnit(CellAddress address, const std::string &unit)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setDisplayUnit(unit);
 }
 
@@ -614,7 +614,7 @@ void PropertySheet::setAlias(CellAddress address, const std::string &alias)
 
     const Cell * aliasedCell = getValueFromAlias(alias);
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
 
     if(aliasedCell == cell)
         return;
@@ -658,14 +658,14 @@ void PropertySheet::setAlias(CellAddress address, const std::string &alias)
 void PropertySheet::setComputedUnit(CellAddress address, const Base::Unit &unit)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setComputedUnit(unit);
 }
 
 void PropertySheet::setSpans(CellAddress address, int rows, int columns)
 {
     Cell * cell = nonNullCellAt(address);
-    assert(cell != 0);
+    assert(cell != nullptr);
     cell->setSpans(rows, columns);
 }
 
@@ -1118,7 +1118,7 @@ void PropertySheet::addDependencies(CellAddress key)
 
     const Expression * expression = cell->getExpression();
 
-    if (expression == 0)
+    if (expression == nullptr)
         return;
 
     for(auto &var : expression->getIdentifiers()) {
@@ -1589,7 +1589,7 @@ Property *PropertySheet::CopyOnImportExternal(
         changed[d.first] = std::move(expr);
     }
     if(changed.empty())
-        return 0;
+        return nullptr;
     std::unique_ptr<PropertySheet> copy(new PropertySheet(*this));
     for(auto &change : changed) 
         copy->data[change.first]->setExpression(std::move(change.second));
@@ -1609,7 +1609,7 @@ Property *PropertySheet::CopyOnLabelChange(App::DocumentObject *obj,
         changed[d.first] = std::move(expr);
     }
     if(changed.empty())
-        return 0;
+        return nullptr;
     std::unique_ptr<PropertySheet> copy(new PropertySheet(*this));
     for(auto &change : changed) 
         copy->data[change.first]->setExpression(std::move(change.second));
@@ -1629,7 +1629,7 @@ Property *PropertySheet::CopyOnLinkReplace(const App::DocumentObject *parent,
         changed[d.first] = std::move(expr);
     }
     if(changed.empty())
-        return 0;
+        return nullptr;
     std::unique_ptr<PropertySheet> copy(new PropertySheet(*this));
     for(auto &change : changed) 
         copy->data[change.first]->setExpression(std::move(change.second));
diff --git a/src/Mod/Spreadsheet/App/PropertySheet.h b/src/Mod/Spreadsheet/App/PropertySheet.h
index b9081e7c29..4b67f8ed46 100644
--- a/src/Mod/Spreadsheet/App/PropertySheet.h
+++ b/src/Mod/Spreadsheet/App/PropertySheet.h
@@ -43,7 +43,7 @@ class SpreadsheetExport PropertySheet : public App::PropertyExpressionContainer
     TYPESYSTEM_HEADER_WITH_OVERRIDE();
 public:
 
-    PropertySheet(Sheet * _owner = 0);
+    PropertySheet(Sheet * _owner = nullptr);
 
     ~PropertySheet();
 
@@ -190,7 +190,7 @@ public:
     unsigned getBindingBorder(App::CellAddress address) const;
 
     bool isBindingPath(const App::ObjectIdentifier &path,
-            App::CellAddress *from=0, App::CellAddress *to=0, bool *href=0) const;
+            App::CellAddress *from=nullptr, App::CellAddress *to=nullptr, bool *href=nullptr) const;
 
     enum BindingType {
         BindingNone,
@@ -198,7 +198,7 @@ public:
         BindingHiddenRef,
     };
     BindingType getBinding(const App::Range &range,
-            App::ExpressionPtr *pStart=0, App::ExpressionPtr *pEnd=0) const;
+            App::ExpressionPtr *pStart=nullptr, App::ExpressionPtr *pEnd=nullptr) const;
 
 protected:
     virtual void hasSetValue() override;
diff --git a/src/Mod/Spreadsheet/App/Sheet.cpp b/src/Mod/Spreadsheet/App/Sheet.cpp
index 1f14deb024..6b9f585e2e 100644
--- a/src/Mod/Spreadsheet/App/Sheet.cpp
+++ b/src/Mod/Spreadsheet/App/Sheet.cpp
@@ -368,7 +368,7 @@ Cell *Sheet::getNewCell(CellAddress address)
 {
      Cell * cell = getCell(address);
 
-    if (cell == 0)
+    if (cell == nullptr)
         cell = cells.createCell(address);
 
     return cell;
@@ -384,7 +384,7 @@ Cell *Sheet::getNewCell(CellAddress address)
 
 void Sheet::setCell(const char * address, const char * contents)
 {
-    assert(address != 0 &&  contents != 0);
+    assert(address != nullptr &&  contents != nullptr);
 
     setCell(CellAddress(address), contents);
 }
@@ -400,7 +400,7 @@ void Sheet::setCell(const char * address, const char * contents)
 
 void Sheet::setCell(CellAddress address, const char * value)
 {
-    assert(value != 0);
+    assert(value != nullptr);
 
 
     if (*value == '\0') {
@@ -524,7 +524,7 @@ Property * Sheet::setFloatProperty(CellAddress key, double value)
             this->removeDynamicProperty(name.c_str());
             propAddress.erase(prop);
         }
-        floatProp = freecad_dynamic_cast<PropertyFloat>(addDynamicProperty("App::PropertyFloat", name.c_str(), 0, 0, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
+        floatProp = freecad_dynamic_cast<PropertyFloat>(addDynamicProperty("App::PropertyFloat", name.c_str(), nullptr, nullptr, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
     }
     else
         floatProp = static_cast<PropertyFloat*>(prop);
@@ -547,7 +547,7 @@ Property * Sheet::setIntegerProperty(CellAddress key, long value)
             propAddress.erase(prop);
         }
         intProp = freecad_dynamic_cast<PropertyInteger>(addDynamicProperty(
-                    "App::PropertyInteger", name.c_str(), 0, 0, 
+                    "App::PropertyInteger", name.c_str(), nullptr, nullptr, 
                     Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
     }
     else
@@ -581,7 +581,7 @@ Property * Sheet::setQuantityProperty(CellAddress key, double value, const Base:
             this->removeDynamicProperty(name.c_str());
             propAddress.erase(prop);
         }
-        Property * p = addDynamicProperty("Spreadsheet::PropertySpreadsheetQuantity", name.c_str(), 0, 0, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist);
+        Property * p = addDynamicProperty("Spreadsheet::PropertySpreadsheetQuantity", name.c_str(), nullptr, nullptr, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist);
         quantityProp = freecad_dynamic_cast<PropertySpreadsheetQuantity>(p);
     }
     else
@@ -616,7 +616,7 @@ Property * Sheet::setStringProperty(CellAddress key, const std::string & value)
             this->removeDynamicProperty(name.c_str());
             propAddress.erase(prop);
         }
-        stringProp = freecad_dynamic_cast<PropertyString>(addDynamicProperty("App::PropertyString", name.c_str(), 0, 0, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
+        stringProp = freecad_dynamic_cast<PropertyString>(addDynamicProperty("App::PropertyString", name.c_str(), nullptr, nullptr, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
     }
 
     propAddress[stringProp] = key;
@@ -636,7 +636,7 @@ Property * Sheet::setObjectProperty(CellAddress key, Py::Object object)
             this->removeDynamicProperty(name.c_str());
             propAddress.erase(prop);
         }
-        pyProp = freecad_dynamic_cast<PropertyPythonObject>(addDynamicProperty("App::PropertyPythonObject", name.c_str(), 0, 0, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
+        pyProp = freecad_dynamic_cast<PropertyPythonObject>(addDynamicProperty("App::PropertyPythonObject", name.c_str(), nullptr, nullptr, Prop_ReadOnly | Prop_Hidden | Prop_NoPersist));
     }
 
     propAddress[pyProp] = key;
@@ -672,7 +672,7 @@ void Sheet::updateProperty(CellAddress key)
 {
     Cell * cell = getCell(key);
 
-    if (cell != 0) {
+    if (cell != nullptr) {
         std::unique_ptr<Expression> output;
         const Expression * input = cell->getExpression();
 
@@ -736,7 +736,7 @@ void Sheet::updateProperty(CellAddress key)
 Property *Sheet::getPropertyByName(const char* name) const
 {
     CellAddress addr = getCellAddress(name,true);
-    Property *prop = 0;
+    Property *prop = nullptr;
     if(addr.isValid())
         prop = getProperty(addr);
     if (prop)
@@ -747,7 +747,7 @@ Property *Sheet::getPropertyByName(const char* name) const
 
 Property *Sheet::getDynamicPropertyByName(const char* name) const {
     CellAddress addr = getCellAddress(name,true);
-    Property *prop = 0;
+    Property *prop = nullptr;
     if(addr.isValid())
         prop = getProperty(addr);
     if (prop)
diff --git a/src/Mod/Spreadsheet/App/Sheet.h b/src/Mod/Spreadsheet/App/Sheet.h
index 49dea4f756..c874988c5c 100644
--- a/src/Mod/Spreadsheet/App/Sheet.h
+++ b/src/Mod/Spreadsheet/App/Sheet.h
@@ -108,7 +108,7 @@ public:
     unsigned getCellBindingBorder(App::CellAddress address) const;
 
     PropertySheet::BindingType getCellBinding(App::Range &range,
-            App::ExpressionPtr *pStart=0, App::ExpressionPtr *pEnd=0) const;
+            App::ExpressionPtr *pStart=nullptr, App::ExpressionPtr *pEnd=nullptr) const;
 
     void setCell(const char *address, const char *value);
 
diff --git a/src/Mod/Spreadsheet/App/SheetObserver.cpp b/src/Mod/Spreadsheet/App/SheetObserver.cpp
index 51c8ac3320..4c9a0dc87d 100644
--- a/src/Mod/Spreadsheet/App/SheetObserver.cpp
+++ b/src/Mod/Spreadsheet/App/SheetObserver.cpp
@@ -75,7 +75,7 @@ void SheetObserver::slotChangedObject(const DocumentObject &Obj, const Property
     else {
         const char * name = Obj.getPropertyName(&Prop);
 
-        if (name == 0)
+        if (name == nullptr)
             return;
 
         if (isUpdating.find(name) != isUpdating.end())
diff --git a/src/Mod/Spreadsheet/App/SheetPyImp.cpp b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
index 815f0c96a5..217bd8e25a 100644
--- a/src/Mod/Spreadsheet/App/SheetPyImp.cpp
+++ b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
@@ -64,7 +64,7 @@ PyObject* SheetPy::set(PyObject *args)
 
 
     if (!PyArg_ParseTuple(args, "ss:set", &address, &contents))
-        return 0;
+        return nullptr;
 
     try {
         Sheet * sheet = getSheetPtr();
@@ -83,7 +83,7 @@ PyObject* SheetPy::set(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     Py_Return;
@@ -92,10 +92,10 @@ PyObject* SheetPy::set(PyObject *args)
 PyObject* SheetPy::get(PyObject *args)
 {
     const char *address;
-    const char *address2=0;
+    const char *address2=nullptr;
 
     if (!PyArg_ParseTuple(args, "s|s:get", &address, &address2))
-        return 0;
+        return nullptr;
 
     PY_TRY {
         if(address2) {
@@ -113,7 +113,7 @@ PyObject* SheetPy::get(PyObject *args)
                 if(!prop) {
                     PyErr_Format(PyExc_ValueError, "Invalid address '%s' in range %s:%s",
                             range.address().c_str(), address, address2);
-                    return 0;
+                    return nullptr;
                 }
                 tuple.setItem(i++,Py::Object(prop->getPyObject(),true));
             }while(range.next());
@@ -123,10 +123,10 @@ PyObject* SheetPy::get(PyObject *args)
 
     App::Property * prop = this->getSheetPtr()->getPropertyByName(address);
 
-    if (prop == 0) {
+    if (prop == nullptr) {
         PyErr_Format(PyExc_ValueError, 
                 "Invalid cell address or property: %s",address);
-        return 0;
+        return nullptr;
     }
     return prop->getPyObject();
 }
@@ -137,7 +137,7 @@ PyObject* SheetPy::getContents(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:getContents", &strAddress))
-        return 0;
+        return nullptr;
 
     PY_TRY {
         try {        
@@ -151,7 +151,7 @@ PyObject* SheetPy::getContents(PyObject *args)
         }
         catch (const Base::Exception & e) {
             PyErr_SetString(PyExc_ValueError, e.what());
-            return 0;
+            return nullptr;
         }
 
         std::string contents;
@@ -170,7 +170,7 @@ PyObject* SheetPy::clear(PyObject *args)
     int all = 1;
 
     if (!PyArg_ParseTuple(args, "s|p:clear", &strAddress, &all))
-        return 0;
+        return nullptr;
 
     try {
         Range rangeIter(strAddress);
@@ -180,7 +180,7 @@ PyObject* SheetPy::clear(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     Py_Return;
@@ -189,7 +189,7 @@ PyObject* SheetPy::clear(PyObject *args)
 PyObject* SheetPy::clearAll(PyObject *args)
 {
     if (!PyArg_ParseTuple(args, ""))
-        return 0;
+        return nullptr;
 
     this->getSheetPtr()->clearAll();
     Py_Return;
@@ -203,7 +203,7 @@ PyObject* SheetPy::importFile(PyObject *args)
     const char * escapeChar = "\\";
 
     if (!PyArg_ParseTuple(args, "s|sss:importFile", &filename, &delimiter, &quoteChar, &escapeChar))
-        return 0;
+        return nullptr;
 
     if (getSheetPtr()->importFromFile(filename, delimiter[0], quoteChar[0], escapeChar[0]))
         return Py::new_reference_to( Py::Boolean(true) );
@@ -219,7 +219,7 @@ PyObject* SheetPy::exportFile(PyObject *args)
     const char * escapeChar = "\\";
 
     if (!PyArg_ParseTuple(args, "s|sss:exportFile", &filename, &delimiter, &quoteChar, &escapeChar))
-        return 0;
+        return nullptr;
 
     if (getSheetPtr()->exportToFile(filename, delimiter[0], quoteChar[0], escapeChar[0]))
         return Py::new_reference_to( Py::Boolean(true) );
@@ -232,7 +232,7 @@ PyObject* SheetPy::mergeCells(PyObject *args)
     const char * range;
 
     if (!PyArg_ParseTuple(args, "s:mergeCells", &range))
-        return 0;
+        return nullptr;
 
     getSheetPtr()->mergeCells(Range(range));
     Py_Return;
@@ -243,7 +243,7 @@ PyObject* SheetPy::splitCell(PyObject *args)
     const char * strAddress;
 
     if (!PyArg_ParseTuple(args, "s:splitCell", &strAddress))
-        return 0;
+        return nullptr;
 
     CellAddress address;
     try {
@@ -251,7 +251,7 @@ PyObject* SheetPy::splitCell(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     getSheetPtr()->splitCell(address);
@@ -264,7 +264,7 @@ PyObject* SheetPy::insertColumns(PyObject *args)
     int count;
 
     if (!PyArg_ParseTuple(args, "si:insertColumns", &column, &count))
-        return 0;
+        return nullptr;
 
     getSheetPtr()->insertColumns(decodeColumn(column), count);
     Py_Return;
@@ -276,7 +276,7 @@ PyObject* SheetPy::removeColumns(PyObject *args)
     int count;
 
     if (!PyArg_ParseTuple(args, "si:removeColumns", &column, &count))
-        return 0;
+        return nullptr;
 
     getSheetPtr()->removeColumns(decodeColumn(column), count);
     Py_Return;
@@ -288,7 +288,7 @@ PyObject* SheetPy::insertRows(PyObject *args)
     int count;
 
     if (!PyArg_ParseTuple(args, "si:insertRows", &row, &count))
-        return 0;
+        return nullptr;
 
     getSheetPtr()->insertRows(decodeRow(std::string(row)), count);
     Py_Return;
@@ -300,7 +300,7 @@ PyObject* SheetPy::removeRows(PyObject *args)
     int count;
 
     if (!PyArg_ParseTuple(args, "si:removeRows", &row, &count))
-        return 0;
+        return nullptr;
 
     getSheetPtr()->removeRows(decodeRow(std::string(row)), count);
     Py_Return;
@@ -314,7 +314,7 @@ PyObject* SheetPy::setStyle(PyObject *args)
     const char * options = "replace";
 
     if (!PyArg_ParseTuple(args, "sO|s:setStyle", &cell, &value, &options))
-        return 0;
+        return nullptr;
 
     if (PySet_Check(value)) {
         PyObject * copy = PySet_New(value);
@@ -329,7 +329,7 @@ PyObject* SheetPy::setStyle(PyObject *args)
                 std::string error = std::string("type of the set need to be a string, not ") + item->ob_type->tp_name;
                 PyErr_SetString(PyExc_TypeError, error.c_str());
                 Py_DECREF(copy);
-                return 0;
+                return nullptr;
             }
         }
         Py_DECREF(copy);
@@ -347,7 +347,7 @@ PyObject* SheetPy::setStyle(PyObject *args)
     else {
         std::string error = std::string("style must be either set or string, not ") + value->ob_type->tp_name;
         PyErr_SetString(PyExc_TypeError, error.c_str());
-        return 0;
+        return nullptr;
     }
 
     if (strcmp(options, "replace") == 0) {
@@ -421,7 +421,7 @@ PyObject* SheetPy::setStyle(PyObject *args)
     }
     else {
         PyErr_SetString(PyExc_ValueError, "Optional parameter must be either 'replace', 'add', 'remove', or 'invert'");
-        return 0;
+        return nullptr;
     }
 
     Py_Return;
@@ -433,21 +433,21 @@ PyObject* SheetPy::getStyle(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:getStyle", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     std::set<std::string> style;
     const Cell * cell = getSheetPtr()->getCell(address);
 
     if (cell && cell->getStyle(style)) {
-        PyObject * s = PySet_New(NULL);
+        PyObject * s = PySet_New(nullptr);
 
         for (std::set<std::string>::const_iterator i = style.begin(); i != style.end(); ++i)
             PySet_Add(s, PyUnicode_FromString((*i).c_str()));
@@ -466,7 +466,7 @@ PyObject* SheetPy::setDisplayUnit(PyObject *args)
     const char * value;
 
     if (!PyArg_ParseTuple(args, "ss:setDisplayUnit", &cell, &value))
-        return 0;
+        return nullptr;
 
     try {
         Range rangeIter(cell);
@@ -477,7 +477,7 @@ PyObject* SheetPy::setDisplayUnit(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     Py_Return;
@@ -490,7 +490,7 @@ PyObject* SheetPy::setAlias(PyObject *args)
     PyObject * value;
 
     if (!PyArg_ParseTuple(args, "sO:setAlias", &strAddress, &value))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
@@ -505,7 +505,7 @@ PyObject* SheetPy::setAlias(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -514,7 +514,7 @@ PyObject* SheetPy::getAlias(PyObject *args)
     const char * strAddress;
 
     if (!PyArg_ParseTuple(args, "s:getAlias", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         CellAddress address(strAddress);
@@ -530,7 +530,7 @@ PyObject* SheetPy::getAlias(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -539,7 +539,7 @@ PyObject* SheetPy::getCellFromAlias(PyObject *args)
     const char * alias;
 
     if (!PyArg_ParseTuple(args, "s:getAlias", &alias))
-        return 0;
+        return nullptr;
 
     try {
         std::string address = getSheetPtr()->getAddressFromAlias(alias);
@@ -553,7 +553,7 @@ PyObject* SheetPy::getCellFromAlias(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -563,7 +563,7 @@ PyObject* SheetPy::getDisplayUnit(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:getDisplayUnit", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
@@ -579,7 +579,7 @@ PyObject* SheetPy::getDisplayUnit(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -591,7 +591,7 @@ PyObject* SheetPy::setAlignment(PyObject *args)
     const char * options = "replace";
 
     if (!PyArg_ParseTuple(args, "sO|s:setAlignment", &cell, &value, &options))
-        return 0;
+        return nullptr;
 
     if (PySet_Check(value)) {
         // Argument is a set of strings
@@ -607,7 +607,7 @@ PyObject* SheetPy::setAlignment(PyObject *args)
                 std::string error = std::string("type of the key need to be a string, not") + item->ob_type->tp_name;
                 PyErr_SetString(PyExc_TypeError, error.c_str());
                 Py_DECREF(copy);
-                return 0;
+                return nullptr;
             }
         }
 
@@ -629,7 +629,7 @@ PyObject* SheetPy::setAlignment(PyObject *args)
     else {
         std::string error = std::string("style must be either set or string, not ") + value->ob_type->tp_name;
         PyErr_SetString(PyExc_TypeError, error.c_str());
-        return 0;
+        return nullptr;
     }
 
     // Set alignment depending on 'options' variable
@@ -660,7 +660,7 @@ PyObject* SheetPy::setAlignment(PyObject *args)
     }
     else {
         PyErr_SetString(PyExc_ValueError, "Optional parameter must be either 'replace' or 'keep'");
-        return 0;
+        return nullptr;
     }
     Py_Return;
 }
@@ -671,21 +671,21 @@ PyObject* SheetPy::getAlignment(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:getAlignment", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
 
     int alignment;
     const  Cell * cell = getSheetPtr()->getCell(address);
     if (cell && cell->getAlignment(alignment)) {
-        PyObject * s = PySet_New(NULL);
+        PyObject * s = PySet_New(nullptr);
 
         if (alignment & Cell::ALIGNMENT_LEFT)
             PySet_Add(s, PyUnicode_FromString("left"));
@@ -745,7 +745,7 @@ PyObject* SheetPy::setForeground(PyObject *args)
         Color c;
 
         if (!PyArg_ParseTuple(args, "sO:setForeground", &range, &value))
-            return 0;
+            return nullptr;
 
         decodeColor(value, c);
 
@@ -757,11 +757,11 @@ PyObject* SheetPy::setForeground(PyObject *args)
     }
     catch (const Base::TypeError & e) {
         PyErr_SetString(PyExc_TypeError, e.what());
-        return 0;
+        return nullptr;
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -771,14 +771,14 @@ PyObject* SheetPy::getForeground(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:getForeground", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     Color c;
@@ -807,7 +807,7 @@ PyObject* SheetPy::setBackground(PyObject *args)
         Color c;
 
         if (!PyArg_ParseTuple(args, "sO:setBackground", &strAddress, &value))
-            return 0;
+            return nullptr;
 
         decodeColor(value, c);
         Range rangeIter(strAddress);
@@ -819,11 +819,11 @@ PyObject* SheetPy::setBackground(PyObject *args)
     }
     catch (const Base::TypeError & e) {
         PyErr_SetString(PyExc_TypeError, e.what());
-        return 0;
+        return nullptr;
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -833,14 +833,14 @@ PyObject* SheetPy::getBackground(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "s:setStyle", &strAddress))
-        return 0;
+        return nullptr;
 
     try {
         address = stringToAddress(strAddress);
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 
     Color c;
@@ -868,7 +868,7 @@ PyObject* SheetPy::setColumnWidth(PyObject *args)
     CellAddress address;
 
     if (!PyArg_ParseTuple(args, "si:setColumnWidth", &columnStr, &width))
-        return 0;
+        return nullptr;
 
     try {
         std::string cellAddr = std::string(columnStr) + "1";
@@ -879,7 +879,7 @@ PyObject* SheetPy::setColumnWidth(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -888,7 +888,7 @@ PyObject* SheetPy::getColumnWidth(PyObject *args)
     const char * columnStr;
 
     if (!PyArg_ParseTuple(args, "s:getColumnWidth", &columnStr))
-        return 0;
+        return nullptr;
 
     try {
         CellAddress address(std::string(columnStr) + "1");
@@ -897,7 +897,7 @@ PyObject* SheetPy::getColumnWidth(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -907,7 +907,7 @@ PyObject* SheetPy::setRowHeight(PyObject *args)
     int height;
 
     if (!PyArg_ParseTuple(args, "si:setRowHeight", &rowStr, &height))
-        return 0;
+        return nullptr;
 
     try {
         CellAddress address("A" + std::string(rowStr));
@@ -917,7 +917,7 @@ PyObject* SheetPy::setRowHeight(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
@@ -926,7 +926,7 @@ PyObject* SheetPy::getRowHeight(PyObject *args)
     const char * rowStr;
 
     if (!PyArg_ParseTuple(args, "s:getRowHeight", &rowStr))
-        return 0;
+        return nullptr;
 
     try {
         CellAddress address("A" + std::string(rowStr));
@@ -935,16 +935,16 @@ PyObject* SheetPy::getRowHeight(PyObject *args)
     }
     catch (const Base::Exception & e) {
         PyErr_SetString(PyExc_ValueError, e.what());
-        return 0;
+        return nullptr;
     }
 }
 
 PyObject *SheetPy::touchCells(PyObject *args) {
     const char *address;
-    const char *address2=0;
+    const char *address2=nullptr;
 
     if (!PyArg_ParseTuple(args, "s|s:touchCells", &address, &address2))
-        return 0;
+        return nullptr;
 
     PY_TRY {
         std::string a1 = getSheetPtr()->getAddressFromAlias(address);
@@ -966,10 +966,10 @@ PyObject *SheetPy::touchCells(PyObject *args) {
 
 PyObject *SheetPy::recomputeCells(PyObject *args) {
     const char *address;
-    const char *address2=0;
+    const char *address2=nullptr;
 
     if (!PyArg_ParseTuple(args, "s|s:touchCells", &address, &address2))
-        return 0;
+        return nullptr;
 
     PY_TRY {
         std::string a1 = getSheetPtr()->getAddressFromAlias(address);
@@ -993,7 +993,7 @@ PyObject *SheetPy::recomputeCells(PyObject *args) {
 
 PyObject *SheetPy::getCustomAttributes(const char*) const
 {
-    return 0;
+    return nullptr;
 }
 
 int SheetPy::setCustomAttributes(const char* , PyObject* )
diff --git a/src/Mod/Spreadsheet/Gui/AppSpreadsheetGui.cpp b/src/Mod/Spreadsheet/Gui/AppSpreadsheetGui.cpp
index e7f365569e..321b1c2bef 100644
--- a/src/Mod/Spreadsheet/Gui/AppSpreadsheetGui.cpp
+++ b/src/Mod/Spreadsheet/Gui/AppSpreadsheetGui.cpp
@@ -77,7 +77,7 @@ private:
     Py::Object open(const Py::Tuple& args)
     {
         char* Name;
-        const char* DocName=0;
+        const char* DocName=nullptr;
         if (!PyArg_ParseTuple(args.ptr(), "et|s","utf-8",&Name,&DocName))
             throw Py::Exception();
         std::string EncodedName = std::string(Name);
@@ -112,7 +112,7 @@ PyMOD_INIT_FUNC(SpreadsheetGui)
 {
     if (!Gui::Application::Instance) {
         PyErr_SetString(PyExc_ImportError, "Cannot load Gui module in console application.");
-        PyMOD_Return(0);
+        PyMOD_Return(nullptr);
     }
 
     // instantiating the commands
diff --git a/src/Mod/Spreadsheet/Gui/DlgBindSheet.h b/src/Mod/Spreadsheet/Gui/DlgBindSheet.h
index 9afe922e3f..51d20e65de 100644
--- a/src/Mod/Spreadsheet/Gui/DlgBindSheet.h
+++ b/src/Mod/Spreadsheet/Gui/DlgBindSheet.h
@@ -37,7 +37,7 @@ class DlgBindSheet : public QDialog
     Q_OBJECT
     
 public:
-    explicit DlgBindSheet(Spreadsheet::Sheet *sheet, const std::vector<App::Range> &range, QWidget *parent = 0);
+    explicit DlgBindSheet(Spreadsheet::Sheet *sheet, const std::vector<App::Range> &range, QWidget *parent = nullptr);
     ~DlgBindSheet();
     
     void accept();
diff --git a/src/Mod/Spreadsheet/Gui/DlgSettingsImp.h b/src/Mod/Spreadsheet/Gui/DlgSettingsImp.h
index 66f395696d..d65e335044 100644
--- a/src/Mod/Spreadsheet/Gui/DlgSettingsImp.h
+++ b/src/Mod/Spreadsheet/Gui/DlgSettingsImp.h
@@ -40,7 +40,7 @@ class DlgSettingsImp : public Gui::Dialog::PreferencePage
     Q_OBJECT
 
 public:
-    DlgSettingsImp( QWidget* parent = 0 );
+    DlgSettingsImp( QWidget* parent = nullptr );
     ~DlgSettingsImp();
 
 protected:
diff --git a/src/Mod/Spreadsheet/Gui/DlgSheetConf.cpp b/src/Mod/Spreadsheet/Gui/DlgSheetConf.cpp
index 352a0e39af..79873d57ac 100644
--- a/src/Mod/Spreadsheet/Gui/DlgSheetConf.cpp
+++ b/src/Mod/Spreadsheet/Gui/DlgSheetConf.cpp
@@ -150,7 +150,7 @@ App::Property *DlgSheetConf::prepare(CellAddress &from, CellAddress &to,
             }
         }
     }
-    return 0;
+    return nullptr;
 }
 
 void DlgSheetConf::accept()
diff --git a/src/Mod/Spreadsheet/Gui/DlgSheetConf.h b/src/Mod/Spreadsheet/Gui/DlgSheetConf.h
index aaf4e66b10..6d20fc5a31 100644
--- a/src/Mod/Spreadsheet/Gui/DlgSheetConf.h
+++ b/src/Mod/Spreadsheet/Gui/DlgSheetConf.h
@@ -37,7 +37,7 @@ class DlgSheetConf : public QDialog
     Q_OBJECT
     
 public:
-    explicit DlgSheetConf(Spreadsheet::Sheet *sheet, App::Range range, QWidget *parent = 0);
+    explicit DlgSheetConf(Spreadsheet::Sheet *sheet, App::Range range, QWidget *parent = nullptr);
     ~DlgSheetConf();
     
     void accept();
diff --git a/src/Mod/Spreadsheet/Gui/LineEdit.h b/src/Mod/Spreadsheet/Gui/LineEdit.h
index 467e81cb7b..a2b9ed58ee 100644
--- a/src/Mod/Spreadsheet/Gui/LineEdit.h
+++ b/src/Mod/Spreadsheet/Gui/LineEdit.h
@@ -33,7 +33,7 @@ class LineEdit : public Gui::ExpressionLineEdit
 {
     Q_OBJECT
 public:
-    explicit LineEdit(QWidget *parent = 0);
+    explicit LineEdit(QWidget *parent = nullptr);
 
     bool event(QEvent *event);
 
diff --git a/src/Mod/Spreadsheet/Gui/PropertiesDialog.cpp b/src/Mod/Spreadsheet/Gui/PropertiesDialog.cpp
index ab6e95358b..00702f00cd 100644
--- a/src/Mod/Spreadsheet/Gui/PropertiesDialog.cpp
+++ b/src/Mod/Spreadsheet/Gui/PropertiesDialog.cpp
@@ -52,7 +52,7 @@ PropertiesDialog::PropertiesDialog(Sheet *_sheet, const std::vector<Range> &_ran
 
     Cell * cell = sheet->getNewCell(*range);
 
-    assert(cell != 0);
+    assert(cell != nullptr);
 
     (void)cell->getForeground(foregroundColor);
     (void)cell->getBackground(backgroundColor);
diff --git a/src/Mod/Spreadsheet/Gui/PropertiesDialog.h b/src/Mod/Spreadsheet/Gui/PropertiesDialog.h
index 695bdf7d82..6c8acaaa42 100644
--- a/src/Mod/Spreadsheet/Gui/PropertiesDialog.h
+++ b/src/Mod/Spreadsheet/Gui/PropertiesDialog.h
@@ -37,7 +37,7 @@ class PropertiesDialog : public QDialog
     Q_OBJECT
     
 public:
-    explicit PropertiesDialog(Spreadsheet::Sheet *_sheet, const std::vector<App::Range> & _ranges, QWidget *parent = 0);
+    explicit PropertiesDialog(Spreadsheet::Sheet *_sheet, const std::vector<App::Range> & _ranges, QWidget *parent = nullptr);
     ~PropertiesDialog();
     
     void apply();
diff --git a/src/Mod/Spreadsheet/Gui/SheetModel.cpp b/src/Mod/Spreadsheet/Gui/SheetModel.cpp
index 8bb723cb80..38fe3bc07a 100644
--- a/src/Mod/Spreadsheet/Gui/SheetModel.cpp
+++ b/src/Mod/Spreadsheet/Gui/SheetModel.cpp
@@ -81,12 +81,12 @@ int SheetModel::columnCount(const QModelIndex &parent) const
 
 QVariant SheetModel::data(const QModelIndex &index, int role) const
 {
-    static const Cell * emptyCell = new Cell(CellAddress(0, 0), 0);
+    static const Cell * emptyCell = new Cell(CellAddress(0, 0), nullptr);
     int row = index.row();
     int col = index.column();
     const Cell * cell = sheet->getCell(CellAddress(row, col));
 
-    if (cell == 0)
+    if (cell == nullptr)
         cell = emptyCell;
 
 //#define DEBUG_DEPS
diff --git a/src/Mod/Spreadsheet/Gui/SheetModel.h b/src/Mod/Spreadsheet/Gui/SheetModel.h
index f6caf69a26..e52f20fa39 100644
--- a/src/Mod/Spreadsheet/Gui/SheetModel.h
+++ b/src/Mod/Spreadsheet/Gui/SheetModel.h
@@ -37,7 +37,7 @@ class SheetModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    explicit SheetModel(Spreadsheet::Sheet * _sheet, QObject *parent = 0);
+    explicit SheetModel(Spreadsheet::Sheet * _sheet, QObject *parent = nullptr);
     ~SheetModel();
     
     SheetModel(QObject *parent);
diff --git a/src/Mod/Spreadsheet/Gui/SheetTableView.cpp b/src/Mod/Spreadsheet/Gui/SheetTableView.cpp
index 7909973096..c4a6aa0352 100644
--- a/src/Mod/Spreadsheet/Gui/SheetTableView.cpp
+++ b/src/Mod/Spreadsheet/Gui/SheetTableView.cpp
@@ -109,7 +109,7 @@ static std::pair<int, int> selectedMinMaxColumns(QModelIndexList list)
 
 SheetTableView::SheetTableView(QWidget *parent)
     : QTableView(parent)
-    , sheet(0)
+    , sheet(nullptr)
     , tabCounter(0)
 {
     setHorizontalHeader(new SheetViewHeader(this,Qt::Horizontal));
@@ -276,7 +276,7 @@ std::vector<Range> SheetTableView::selectedRanges() const
 
 void SheetTableView::insertRows()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
 
     QModelIndexList rows = selectionModel()->selectedRows();
     std::vector<int> sortedRows;
@@ -313,7 +313,7 @@ void SheetTableView::insertRows()
 
 void SheetTableView::insertRowsAfter()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
     const auto rows = selectionModel()->selectedRows();
     const auto & [min, max] = selectedMinMaxRows(rows);
     assert(max - min == rows.size() - 1);
@@ -327,7 +327,7 @@ void SheetTableView::insertRowsAfter()
 
 void SheetTableView::removeRows()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
 
     QModelIndexList rows = selectionModel()->selectedRows();
     std::vector<int> sortedRows;
@@ -348,7 +348,7 @@ void SheetTableView::removeRows()
 
 void SheetTableView::insertColumns()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
 
     QModelIndexList cols = selectionModel()->selectedColumns();
     std::vector<int> sortedColumns;
@@ -386,7 +386,7 @@ void SheetTableView::insertColumns()
 
 void SheetTableView::insertColumnsAfter()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
     const auto columns = selectionModel()->selectedColumns();
     const auto& [min, max] = selectedMinMaxColumns(columns);
     assert(max - min == columns.size() - 1);
@@ -400,7 +400,7 @@ void SheetTableView::insertColumnsAfter()
 
 void SheetTableView::removeColumns()
 {
-    assert(sheet != 0);
+    assert(sheet != nullptr);
 
     QModelIndexList cols = selectionModel()->selectedColumns();
     std::vector<int> sortedColumns;
@@ -678,7 +678,7 @@ void SheetTableView::pasteClipboard()
         }else{
             QByteArray res = mimeData->data(_SheetMime);
             Base::ByteArrayIStreambuf buf(res);
-            std::istream in(0);
+            std::istream in(nullptr);
             in.rdbuf(&buf);
             Base::XMLReader reader("<memory>", in);
             sheet->getCells()->pasteCells(reader,range);
diff --git a/src/Mod/Spreadsheet/Gui/SheetTableView.h b/src/Mod/Spreadsheet/Gui/SheetTableView.h
index 8a045c4fa6..490111c66a 100644
--- a/src/Mod/Spreadsheet/Gui/SheetTableView.h
+++ b/src/Mod/Spreadsheet/Gui/SheetTableView.h
@@ -52,7 +52,7 @@ class SheetTableView : public QTableView
 {
     Q_OBJECT
 public:
-    explicit SheetTableView(QWidget *parent = 0);
+    explicit SheetTableView(QWidget *parent = nullptr);
     ~SheetTableView();
     
     void edit(const QModelIndex &index);
diff --git a/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.cpp b/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.cpp
index 2eb1647ba3..4d083259f9 100644
--- a/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.cpp
+++ b/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.cpp
@@ -56,7 +56,7 @@ QWidget *SpreadsheetDelegate::createEditor(QWidget *parent,
     App::Range range(addr,addr);
     if(sheet && sheet->getCellBinding(range)) {
         FC_ERR("Bound cell " << addr.toString() << " cannot be edited");
-        return 0;
+        return nullptr;
     }
 
     SpreadsheetGui::LineEdit *editor = new SpreadsheetGui::LineEdit(parent);
diff --git a/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.h b/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.h
index 2a477b1cb1..d7cb3f2ebe 100644
--- a/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.h
+++ b/src/Mod/Spreadsheet/Gui/SpreadsheetDelegate.h
@@ -37,7 +37,7 @@ class SpreadsheetDelegate : public QStyledItemDelegate
 {
     Q_OBJECT
 public:
-    explicit SpreadsheetDelegate(Spreadsheet::Sheet * sheet, QWidget *parent = 0);
+    explicit SpreadsheetDelegate(Spreadsheet::Sheet * sheet, QWidget *parent = nullptr);
     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &,
                           const QModelIndex &index) const;
     void setEditorData(QWidget *editor, const QModelIndex &index) const;
diff --git a/src/Mod/Spreadsheet/Gui/ViewProviderSpreadsheet.cpp b/src/Mod/Spreadsheet/Gui/ViewProviderSpreadsheet.cpp
index f98b8d9710..5bef28a45a 100644
--- a/src/Mod/Spreadsheet/Gui/ViewProviderSpreadsheet.cpp
+++ b/src/Mod/Spreadsheet/Gui/ViewProviderSpreadsheet.cpp
@@ -153,7 +153,7 @@ void ViewProviderSheet::beforeDelete()
     if(!view)
         return;
     if(view==Gui::getMainWindow()->activeWindow())
-        getDocument()->setActiveView(0,Gui::View3DInventor::getClassTypeId());
+        getDocument()->setActiveView(nullptr,Gui::View3DInventor::getClassTypeId());
     Gui::getMainWindow()->removeWindow(view);
 }
 
diff --git a/src/Mod/Spreadsheet/Gui/qtcolorpicker.cpp b/src/Mod/Spreadsheet/Gui/qtcolorpicker.cpp
index 3e15eb38d4..5bf2485ee0 100644
--- a/src/Mod/Spreadsheet/Gui/qtcolorpicker.cpp
+++ b/src/Mod/Spreadsheet/Gui/qtcolorpicker.cpp
@@ -171,7 +171,7 @@ class ColorPickerItem : public QFrame
 
 public:
     ColorPickerItem(const QColor &color = Qt::white, const QString &text = QString(),
-              QWidget *parent = 0);
+              QWidget *parent = nullptr);
     ~ColorPickerItem();
 
     QColor color() const;
@@ -207,7 +207,7 @@ class ColorPickerPopup : public QFrame
 
 public:
     ColorPickerPopup(int width, bool withColorDialog,
-               QWidget *parent = 0);
+               QWidget *parent = nullptr);
     ~ColorPickerPopup();
 
     void insertColor(const QColor &col, const QString &text, int index);
@@ -271,7 +271,7 @@ private:
 */
 QtColorPicker::QtColorPicker(QWidget *parent,
                  int cols, bool enableColorDialog)
-    : QPushButton(parent), popup(0), withColorDialog(enableColorDialog)
+    : QPushButton(parent), popup(nullptr), withColorDialog(enableColorDialog)
 {
     setFocusPolicy(Qt::StrongFocus);
     setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Fixed);
@@ -562,11 +562,11 @@ ColorPickerPopup::ColorPickerPopup(int width, bool withColorDialog,
     moreButton->setFrameRect(QRect(2, 2, 20, 17));
     connect(moreButton, SIGNAL(clicked()), SLOT(getColorFromDialog()));
     } else {
-    moreButton = 0;
+    moreButton = nullptr;
     }
 
-    eventLoop = 0;
-    grid = 0;
+    eventLoop = nullptr;
+    grid = nullptr;
     regenerateGrid();
 }
 
@@ -593,7 +593,7 @@ ColorPickerItem *ColorPickerPopup::find(const QColor &col) const
         return items.at(i);
     }
 
-    return 0;
+    return nullptr;
 }
 
 /*! \internal
@@ -659,7 +659,7 @@ void ColorPickerPopup::exec()
     QEventLoop e;
     eventLoop = &e;
     (void) e.exec();
-    eventLoop = 0;
+    eventLoop = nullptr;
 }
 
 /*! \internal
@@ -669,7 +669,7 @@ void ColorPickerPopup::updateSelected()
 {
     QLayoutItem *layoutItem;
     int i = 0;
-    while ((layoutItem = grid->itemAt(i)) != 0) {
+    while ((layoutItem = grid->itemAt(i)) != nullptr) {
     QWidget *w = layoutItem->widget();
     if (w && w->inherits("ColorPickerItem")) {
         ColorPickerItem *litem = reinterpret_cast<ColorPickerItem *>(layoutItem->widget());
@@ -755,7 +755,7 @@ void ColorPickerPopup::keyPressEvent(QKeyEvent *e)
 
         QLayoutItem *layoutItem;
                 int i = 0;
-        while ((layoutItem = grid->itemAt(i)) != 0) {
+        while ((layoutItem = grid->itemAt(i)) != nullptr) {
             QWidget *w = layoutItem->widget();
             if (w && w->inherits("ColorPickerItem")) {
             ColorPickerItem *litem
@@ -775,7 +775,7 @@ void ColorPickerPopup::keyPressEvent(QKeyEvent *e)
 
         QLayoutItem *layoutItem;
                 int i = 0;
-        while ((layoutItem = grid->itemAt(i)) != 0) {
+        while ((layoutItem = grid->itemAt(i)) != nullptr) {
             QWidget *w = layoutItem->widget();
             if (w && w->inherits("ColorPickerItem")) {
             ColorPickerItem *litem
@@ -904,9 +904,9 @@ void ColorPickerPopup::getColorFromDialog()
     //QRgb rgb = QColorDialog::getRgba(lastSel.rgba(), &ok, parentWidget());
     QColor col;
     if (Gui::DialogOptions::dontUseNativeColorDialog()){
-        col = QColorDialog::getColor(lastSel, parentWidget(), 0, QColorDialog::ShowAlphaChannel|QColorDialog::DontUseNativeDialog);
+        col = QColorDialog::getColor(lastSel, parentWidget(), nullptr, QColorDialog::ShowAlphaChannel|QColorDialog::DontUseNativeDialog);
     } else {
-        col = QColorDialog::getColor(lastSel, parentWidget(), 0, QColorDialog::ShowAlphaChannel);
+        col = QColorDialog::getColor(lastSel, parentWidget(), nullptr, QColorDialog::ShowAlphaChannel);
     }
     if (!col.isValid())
     return;
diff --git a/src/Mod/Spreadsheet/Gui/qtcolorpicker.h b/src/Mod/Spreadsheet/Gui/qtcolorpicker.h
index 892ec140b5..6122183b17 100644
--- a/src/Mod/Spreadsheet/Gui/qtcolorpicker.h
+++ b/src/Mod/Spreadsheet/Gui/qtcolorpicker.h
@@ -79,7 +79,7 @@ class QT_QTCOLORPICKER_EXPORT QtColorPicker : public QPushButton
     Q_PROPERTY(bool colorDialog READ colorDialogEnabled WRITE setColorDialogEnabled)
 
 public:
-    QtColorPicker(QWidget *parent = 0,
+    QtColorPicker(QWidget *parent = nullptr,
                   int columns = -1, bool enableColorDialog = true);
 
     ~QtColorPicker();