diff --git a/EvtGen/EvtGen.hh b/EvtGen/EvtGen.hh
--- a/EvtGen/EvtGen.hh
+++ b/EvtGen/EvtGen.hh
@@ -38,14 +38,16 @@
 class EvtGen {
   public:
     EvtGen( const std::string& decayName, const std::string& pdtTableName,
-            EvtRandomEngine* randomEngine = 0, EvtAbsRadCorr* isrEngine = 0,
-            const std::list<EvtDecayBase*>* extraModels = 0, int mixingType = 1,
-            bool useXml = false );
+            EvtRandomEngine* randomEngine = nullptr,
+            EvtAbsRadCorr* isrEngine = nullptr,
+            const std::list<EvtDecayBase*>* extraModels = nullptr,
+            int mixingType = 1, bool useXml = false );
 
     EvtGen( const std::string& decayName, std::istream& pdtTableData,
-            EvtRandomEngine* randomEngine = 0, EvtAbsRadCorr* isrEngine = 0,
-            const std::list<EvtDecayBase*>* extraModels = 0, int mixingType = 1,
-            bool useXml = false );
+            EvtRandomEngine* randomEngine = nullptr,
+            EvtAbsRadCorr* isrEngine = nullptr,
+            const std::list<EvtDecayBase*>* extraModels = nullptr,
+            int mixingType = 1, bool useXml = false );
 
     ~EvtGen();
 
@@ -53,16 +55,15 @@
 
     EvtHepMCEvent* generateDecay( int PDGid, EvtVector4R refFrameP4,
                                   EvtVector4R translation,
-                                  EvtSpinDensity* spinDensity = 0 );
+                                  EvtSpinDensity* spinDensity = nullptr );
 
     void generateDecay( EvtParticle* p );
 
   private:
-
     void initialize( const std::string& decayName, std::istream& pdtTable,
-                     EvtRandomEngine* randomEngine = 0,
-                     EvtAbsRadCorr* isrEngine = 0,
-                     const std::list<EvtDecayBase*>* extraModels = 0,
+                     EvtRandomEngine* randomEngine = nullptr,
+                     EvtAbsRadCorr* isrEngine = nullptr,
+                     const std::list<EvtDecayBase*>* extraModels = nullptr,
                      int mixingType = 1, bool useXml = false );
 
     EvtPDL _pdl;
diff --git a/EvtGenBase/EvtModel.hh b/EvtGenBase/EvtModel.hh
--- a/EvtGenBase/EvtModel.hh
+++ b/EvtGenBase/EvtModel.hh
@@ -55,7 +55,7 @@
 
 inline EvtModel& EvtModel::instance()
 {
-    if ( _instance == 0 )
+    if ( _instance == nullptr )
         _instance = new EvtModel;
     return *_instance;
 }
diff --git a/EvtGenBase/EvtParticle.hh b/EvtGenBase/EvtParticle.hh
--- a/EvtGenBase/EvtParticle.hh
+++ b/EvtGenBase/EvtParticle.hh
@@ -180,7 +180,7 @@
     /**
   * Iterates over the particles in a decay chain.
   */
-    EvtParticle* nextIter( EvtParticle* rootOfTree = 0 );
+    EvtParticle* nextIter( EvtParticle* rootOfTree = nullptr );
 
     /**
   * Makes stdhep list
diff --git a/EvtGenBase/EvtParticleDecay.hh b/EvtGenBase/EvtParticleDecay.hh
--- a/EvtGenBase/EvtParticleDecay.hh
+++ b/EvtGenBase/EvtParticleDecay.hh
@@ -27,14 +27,14 @@
   public:
     EvtParticleDecay()
     {
-        _decay = 0;
+        _decay = nullptr;
         _brfrsum = 0.0;
         _massmin = 0.0;
     }
 
     ~EvtParticleDecay()
     {
-        if ( _decay != 0 )
+        if ( _decay != nullptr )
             delete _decay;
     }
 
diff --git a/EvtGenBase/EvtParticleDecayList.hh b/EvtGenBase/EvtParticleDecayList.hh
--- a/EvtGenBase/EvtParticleDecayList.hh
+++ b/EvtGenBase/EvtParticleDecayList.hh
@@ -29,7 +29,7 @@
   public:
     EvtParticleDecayList()
     {
-        _decaylist = 0;
+        _decaylist = nullptr;
         _nmode = 0;
         _rawbrfrsum = 0;
     }
diff --git a/EvtGenBase/EvtPdf.hh b/EvtGenBase/EvtPdf.hh
--- a/EvtGenBase/EvtPdf.hh
+++ b/EvtGenBase/EvtPdf.hh
@@ -146,7 +146,7 @@
 
     EvtPdfGen() : _pdf( 0 ) {}
     EvtPdfGen( const EvtPdfGen<T>& other ) :
-        _pdf( other._pdf ? other._pdf->clone() : 0 )
+        _pdf( other._pdf ? other._pdf->clone() : nullptr )
     {
     }
     EvtPdfGen( const EvtPdf<T>& pdf ) : _pdf( pdf.clone() ) {}
diff --git a/EvtGenBase/EvtReport.hh b/EvtGenBase/EvtReport.hh
--- a/EvtGenBase/EvtReport.hh
+++ b/EvtGenBase/EvtReport.hh
@@ -54,7 +54,8 @@
 };
 
 // function declaration
-std::ostream& EvtGenReport( EvtGenSeverity severity, const char* facility = 0 );
+std::ostream& EvtGenReport( EvtGenSeverity severity,
+                            const char* facility = nullptr );
 
 // inline function definitions
 
diff --git a/EvtGenBase/EvtStreamInputIterator.hh b/EvtGenBase/EvtStreamInputIterator.hh
--- a/EvtGenBase/EvtStreamInputIterator.hh
+++ b/EvtGenBase/EvtStreamInputIterator.hh
@@ -43,7 +43,7 @@
     EvtStreamInputIterator() : _counter( 0 ) {}
 
     EvtStreamInputIterator( const EvtStreamInputIterator& other ) :
-        _counter( other._counter ? other._counter->clone() : 0 ),
+        _counter( other._counter ? other._counter->clone() : nullptr ),
         _currentValue( other._currentValue )
     {
     }
diff --git a/EvtGenModels/EvtIntervalDecayAmp.hh b/EvtGenModels/EvtIntervalDecayAmp.hh
--- a/EvtGenModels/EvtIntervalDecayAmp.hh
+++ b/EvtGenModels/EvtIntervalDecayAmp.hh
@@ -44,7 +44,7 @@
 template <class T>
 class EvtIntervalDecayAmp : public EvtDecayAmp {
   public:
-    EvtIntervalDecayAmp() : _probMax( 0. ), _nScan( 0 ), _fact( 0 ) {}
+    EvtIntervalDecayAmp() : _probMax( 0. ), _nScan( 0 ), _fact( nullptr ) {}
 
     EvtIntervalDecayAmp( const EvtIntervalDecayAmp<T>& other ) :
         _probMax( other._probMax ), _nScan( other._nScan ), COPY_PTR( _fact )
diff --git a/EvtGenModels/EvtModelReg.hh b/EvtGenModels/EvtModelReg.hh
--- a/EvtGenModels/EvtModelReg.hh
+++ b/EvtGenModels/EvtModelReg.hh
@@ -27,7 +27,7 @@
 
 class EvtModelReg {
   public:
-    EvtModelReg( const std::list<EvtDecayBase*>* extraModels = 0 );
+    EvtModelReg( const std::list<EvtDecayBase*>* extraModels = nullptr );
 
   private:
 };
diff --git a/EvtGenModels/EvtMultibody.hh b/EvtGenModels/EvtMultibody.hh
--- a/EvtGenModels/EvtMultibody.hh
+++ b/EvtGenModels/EvtMultibody.hh
@@ -29,8 +29,8 @@
   public:
     EvtMultibody()
     {
-        _decayTree = NULL;
-        _ilist = NULL;
+        _decayTree = nullptr;
+        _ilist = nullptr;
     }
     ~EvtMultibody();
 
diff --git a/src/EvtGen.cpp b/src/EvtGen.cpp
--- a/src/EvtGen.cpp
+++ b/src/EvtGen.cpp
@@ -91,7 +91,7 @@
 {
     EvtGenReport( EVTGEN_INFO, "EvtGen" ) << "Initializing EvtGen" << endl;
 
-    if ( randomEngine == 0 ) {
+    if ( randomEngine == nullptr ) {
         static EvtSimpleRandomEngine defaultRandomEngine;
         EvtRandom::setRandomEngine( &defaultRandomEngine );
         EvtGenReport( EVTGEN_INFO, "EvtGen" )
@@ -123,7 +123,7 @@
 
     // Set the radiative correction engine
 
-    if ( isrEngine != 0 ) {
+    if ( isrEngine != nullptr ) {
         EvtRadCorr::setRadCorrEngine( isrEngine );
 
     } else {
@@ -164,9 +164,9 @@
                                       EvtVector4R translation,
                                       EvtSpinDensity* spinDensity )
 {
-    EvtParticle* theParticle( 0 );
+    EvtParticle* theParticle( nullptr );
 
-    if ( spinDensity == 0 ) {
+    if ( spinDensity == nullptr ) {
         theParticle = EvtParticleFactory::particleFactory(
             EvtPDL::evtIdFromStdHep( PDGId ), refFrameP4 );
     } else {
diff --git a/src/EvtGenBase/EvtCPUtil.cpp b/src/EvtGenBase/EvtCPUtil.cpp
--- a/src/EvtGenBase/EvtCPUtil.cpp
+++ b/src/EvtGenBase/EvtCPUtil.cpp
@@ -42,9 +42,9 @@
 
 EvtCPUtil* EvtCPUtil::getInstance()
 {
-    static EvtCPUtil* theCPUtil = 0;
+    static EvtCPUtil* theCPUtil = nullptr;
 
-    if ( theCPUtil == 0 ) {
+    if ( theCPUtil == nullptr ) {
         theCPUtil = new EvtCPUtil( 1 );
     }
 
@@ -179,20 +179,21 @@
 
     bool incoherentmix = false;
 
-    if ( ( parent != 0 ) && ( parent->getId() == B0 || parent->getId() == B0B ||
-                              parent->getId() == BS || parent->getId() == BSB ) ) {
+    if ( ( parent != nullptr ) &&
+         ( parent->getId() == B0 || parent->getId() == B0B ||
+           parent->getId() == BS || parent->getId() == BSB ) ) {
         incoherentmix = true;
     }
 
     if ( incoherentmix )
         parent = parent->getParent();
 
-    if ( parent == 0 || parent->getId() != UPS4S ) {
+    if ( parent == nullptr || parent->getId() != UPS4S ) {
         //Need to make this more general, but for now
         //assume no parent. If we have parent of B we
         //need to charge conj. full decay tree.
 
-        if ( parent != 0 ) {
+        if ( parent != nullptr ) {
             EvtGenReport( EVTGEN_INFO, "EvtGen" )
                 << "p=" << EvtPDL::name( p->getId() )
                 << " parent=" << EvtPDL::name( parent->getId() ) << endl;
@@ -231,7 +232,7 @@
         }
     }
 
-    if ( parent != 0 ) {
+    if ( parent != nullptr ) {
         //if (entryCount>1){
         //  EvtGenReport(EVTGEN_INFO,"EvtGen") << "Double CP decay:"<<entryCount<<endl;
         //}
@@ -385,7 +386,8 @@
         static double ctau = ctauL < ctauH ? ctauH : ctauL;
         t = -log( EvtRandom::Flat() ) * ctau;
         EvtParticle* parent = p->getParent();
-        if ( parent != 0 && ( parent->getId() == BS0 || parent->getId() == BSB ) ) {
+        if ( parent != nullptr &&
+             ( parent->getId() == BS0 || parent->getId() == BSB ) ) {
             if ( parent->getId() == BS0 )
                 otherb = BSB;
             if ( parent->getId() == BSB )
@@ -407,7 +409,8 @@
         static double ctau = ctauL < ctauH ? ctauH : ctauL;
         t = -log( EvtRandom::Flat() ) * ctau;
         EvtParticle* parent = p->getParent();
-        if ( parent != 0 && ( parent->getId() == D0 || parent->getId() == D0B ) ) {
+        if ( parent != nullptr &&
+             ( parent->getId() == D0 || parent->getId() == D0B ) ) {
             if ( parent->getId() == D0 )
                 otherb = D0B;
             if ( parent->getId() == D0B )
@@ -429,7 +432,7 @@
 
     EvtParticle* parent = p->getParent();
 
-    if ( parent == 0 || parent->getId() != UPS4 ) {
+    if ( parent == nullptr || parent->getId() != UPS4 ) {
         //EvtGenReport(EVTGEN_ERROR,"EvtGen") <<
         //  "Warning CP violation with B having no parent!"<<endl;
         t = p->getLifetime();
diff --git a/src/EvtGenBase/EvtCyclic3.cpp b/src/EvtGenBase/EvtCyclic3.cpp
--- a/src/EvtGenBase/EvtCyclic3.cpp
+++ b/src/EvtGenBase/EvtCyclic3.cpp
@@ -331,7 +331,7 @@
             return "C";
     }
     assert( 0 );
-    return 0;    // sngh
+    return nullptr;    // sngh
 }
 
 const char* EvtCyclic3::c_str( Pair i )
@@ -345,7 +345,7 @@
             return "AB";
     }
     assert( 0 );
-    return 0;    // sngh
+    return nullptr;    // sngh
 }
 
 const char* EvtCyclic3::c_str( Perm p )
diff --git a/src/EvtGenBase/EvtDecayAmp.cpp b/src/EvtGenBase/EvtDecayAmp.cpp
--- a/src/EvtGenBase/EvtDecayAmp.cpp
+++ b/src/EvtGenBase/EvtDecayAmp.cpp
@@ -79,7 +79,7 @@
                 << "channel        :" << p->getChannel() << endl;
             EvtGenReport( EVTGEN_DEBUG, "EvtGen" )
                 << "Momentum:" << p->getP4() << " " << p->mass() << endl;
-            if ( p->getParent() != 0 ) {
+            if ( p->getParent() != nullptr ) {
                 EvtGenReport( EVTGEN_DEBUG, "EvtGen" )
                     << "parent:"
                     << EvtPDL::name( p->getParent()->getId() ).c_str() << endl;
@@ -189,20 +189,20 @@
 
                     for ( size_t idaug = 0; idaug < p->getNDaug(); idaug++ ) {
                         EvtParticle* daughter = p->getDaug( idaug );
-                        if ( daughter != 0 ) {
+                        if ( daughter != nullptr ) {
                             daughter->printTree();
                         }
                     }
 
                     EvtParticle* pParent = p->getParent();
-                    if ( pParent != 0 ) {
+                    if ( pParent != nullptr ) {
                         EvtGenReport( EVTGEN_ERROR, "EvtGen" )
                             << "Parent:"
                             << EvtPDL::name( pParent->getId() ).c_str() << endl;
 
                         EvtParticle* grandParent = pParent->getParent();
 
-                        if ( grandParent != 0 ) {
+                        if ( grandParent != nullptr ) {
                             EvtGenReport( EVTGEN_ERROR, "EvtGen" )
                                 << "GrandParent:"
                                 << EvtPDL::name( grandParent->getId() ).c_str()
diff --git a/src/EvtGenBase/EvtDecayBase.cpp b/src/EvtGenBase/EvtDecayBase.cpp
--- a/src/EvtGenBase/EvtDecayBase.cpp
+++ b/src/EvtGenBase/EvtDecayBase.cpp
@@ -621,7 +621,7 @@
         i++;
     }
 
-    char** tc = 0;
+    char** tc = nullptr;
     double result = strtod( _args[j].c_str(), tc );
 
     if ( _storedArgs.size() < j + 1 ) {    // then store the argument's value
diff --git a/src/EvtGenBase/EvtDecayParm.cpp b/src/EvtGenBase/EvtDecayParm.cpp
--- a/src/EvtGenBase/EvtDecayParm.cpp
+++ b/src/EvtGenBase/EvtDecayParm.cpp
@@ -51,22 +51,22 @@
 
 EvtDecayParm::EvtDecayParm()
 {
-    itsfcn = 0;
+    itsfcn = nullptr;
     itsndaug = 0;
     itsnarg = 0;
-    itsdaugs = 0;
-    itsargs = 0;
+    itsdaugs = nullptr;
+    itsargs = nullptr;
 
     modelname = "**********";
 }
 
 EvtDecayParm::~EvtDecayParm()
 {
-    if ( itsdaugs != 0 ) {
+    if ( itsdaugs != nullptr ) {
         delete[] itsdaugs;
     }
 
-    if ( itsargs != 0 ) {
+    if ( itsargs != nullptr ) {
         delete[] itsargs;
     }
 }
diff --git a/src/EvtGenBase/EvtDecayTable.cpp b/src/EvtGenBase/EvtDecayTable.cpp
--- a/src/EvtGenBase/EvtDecayTable.cpp
+++ b/src/EvtGenBase/EvtDecayTable.cpp
@@ -58,9 +58,9 @@
 
 EvtDecayTable* EvtDecayTable::getInstance()
 {
-    static EvtDecayTable* theDecayTable = 0;
+    static EvtDecayTable* theDecayTable = nullptr;
 
-    if ( theDecayTable == 0 ) {
+    if ( theDecayTable == nullptr ) {
         theDecayTable = new EvtDecayTable();
     }
 
@@ -91,7 +91,7 @@
     partnum = p->getId().getAlias();
 
     if ( _decaytable[partnum].getNMode() == 0 )
-        return 0;
+        return nullptr;
     return _decaytable[partnum].getDecayModel( p );
 }
 
@@ -1445,7 +1445,7 @@
 
 EvtDecayBase* EvtDecayTable::findDecayModel( int aliasInt, int modeInt )
 {
-    EvtDecayBase* theModel( 0 );
+    EvtDecayBase* theModel( nullptr );
 
     if ( aliasInt >= 0 && aliasInt < (int)EvtPDL::entries() ) {
         theModel = _decaytable[aliasInt].getDecayModel( modeInt );
diff --git a/src/EvtGenBase/EvtExtGeneratorCommandsTable.cpp b/src/EvtGenBase/EvtExtGeneratorCommandsTable.cpp
--- a/src/EvtGenBase/EvtExtGeneratorCommandsTable.cpp
+++ b/src/EvtGenBase/EvtExtGeneratorCommandsTable.cpp
@@ -32,9 +32,9 @@
 
 EvtExtGeneratorCommandsTable* EvtExtGeneratorCommandsTable::getInstance()
 {
-    static EvtExtGeneratorCommandsTable* theCommandMap = 0;
+    static EvtExtGeneratorCommandsTable* theCommandMap = nullptr;
 
-    if ( theCommandMap == 0 ) {
+    if ( theCommandMap == nullptr ) {
         theCommandMap = new EvtExtGeneratorCommandsTable();
     }
 
diff --git a/src/EvtGenBase/EvtHepMCEvent.cpp b/src/EvtGenBase/EvtHepMCEvent.cpp
--- a/src/EvtGenBase/EvtHepMCEvent.cpp
+++ b/src/EvtGenBase/EvtHepMCEvent.cpp
@@ -25,7 +25,7 @@
 #include "EvtGenBase/EvtPatches.hh"
 
 EvtHepMCEvent::EvtHepMCEvent() :
-    _theEvent( 0 ), _translation( 0.0, 0.0, 0.0, 0.0 )
+    _theEvent( nullptr ), _translation( 0.0, 0.0, 0.0, 0.0 )
 {
 }
 
@@ -36,10 +36,10 @@
 
 void EvtHepMCEvent::deleteEvent()
 {
-    if ( _theEvent != 0 ) {
+    if ( _theEvent != nullptr ) {
         _theEvent->clear();
         delete _theEvent;
-        _theEvent = 0;
+        _theEvent = nullptr;
     }
 }
 
@@ -56,7 +56,7 @@
     // Rather, it uses the base particle to construct the event.
 
     this->deleteEvent();
-    if ( baseParticle == 0 ) {
+    if ( baseParticle == nullptr ) {
         return;
     }
 
@@ -79,7 +79,7 @@
     // Create an HepMC GenParticle, with the 4-momenta in the frame given by the frameType integer
     GenParticlePtr genParticle{nullptr};
 
-    if ( theParticle != 0 ) {
+    if ( theParticle != nullptr ) {
         // Set the particle status integer to either stable or decayed
         int status( EvtHepMCEvent::STABLE );
         int nDaug = theParticle->getNDaug();
@@ -127,7 +127,8 @@
     // be the same GenParticle pointer, hence the reason for using it as a 2nd argument
     // in this function.
 
-    if ( _theEvent == 0 || inEvtParticle == 0 || inGenParticle == 0 ) {
+    if ( _theEvent == nullptr || inEvtParticle == nullptr ||
+         inGenParticle == nullptr ) {
         return;
     }
 
@@ -150,7 +151,7 @@
         GenParticlePtr genDaughter =
             this->createGenParticle( evtDaughter, EvtHepMCEvent::LAB );
 
-        if ( genDaughter != 0 ) {
+        if ( genDaughter != nullptr ) {
             // Add a new GenParticle (outgoing) particle daughter to the vertex
             theVertex->add_particle_out( genDaughter );
 
@@ -173,13 +174,13 @@
 {
     FourVector vertexCoord( 0.0, 0.0, 0.0, 0.0 );
 
-    if ( theParticle != 0 && theParticle->getNDaug() != 0 ) {
+    if ( theParticle != nullptr && theParticle->getNDaug() != 0 ) {
         // Get the position (t,x,y,z) of the EvtParticle, offset by the translation vector.
         // This position will be the point where the particle decays. So we ask
         // the position of the (1st) daughter particle.
         EvtParticle* daugParticle = theParticle->getDaug( 0 );
 
-        if ( daugParticle != 0 ) {
+        if ( daugParticle != nullptr ) {
             EvtVector4R vtxPosition = daugParticle->get4Pos() + _translation;
 
             // Create the HepMC 4 vector of the position (x,y,z,t)
diff --git a/src/EvtGenBase/EvtMHelAmp.cpp b/src/EvtGenBase/EvtMHelAmp.cpp
--- a/src/EvtGenBase/EvtMHelAmp.cpp
+++ b/src/EvtGenBase/EvtMHelAmp.cpp
@@ -34,7 +34,7 @@
 {
     _id = id;
     _twospin = EvtSpinType::getSpin2( EvtPDL::getSpinType( id ) );
-    _parent = NULL;
+    _parent = nullptr;
     _lineshape = lineshape;
 
     _elem = elem;
@@ -82,7 +82,7 @@
     EvtVector4R d = _children[0]->get4vector( product );
     double phi, theta;
 
-    if ( _parent == NULL ) {
+    if ( _parent == nullptr ) {
         // This means that we're calculating the first level and we need to just
         // calculate the polar and azymuthal angles daughters in rest frame of
         // this (root) particle (this is automatic).
@@ -97,7 +97,7 @@
 
         // See if we have a grandparent - if no then the z-axis is defined by
         // the z-axis of the root particle
-        EvtVector4R g = _parent->getparent() == NULL
+        EvtVector4R g = _parent->getparent() == nullptr
                             ? EvtVector4R( 0.0, 0.0, 0.0, 1.0 )
                             : _parent->getparent()->get4vector( product );
 
diff --git a/src/EvtGenBase/EvtMTree.cpp b/src/EvtGenBase/EvtMTree.cpp
--- a/src/EvtGenBase/EvtMTree.cpp
+++ b/src/EvtGenBase/EvtMTree.cpp
@@ -86,8 +86,8 @@
                                   const vector<EvtComplex>& amps,
                                   const vector<EvtMNode*>& children )
 {
-    EvtMRes* resonance = NULL;
-    EvtMLineShape* lineshape = NULL;
+    EvtMRes* resonance = nullptr;
+    EvtMLineShape* lineshape = nullptr;
 
     if ( ls == "BREITWIGNER" ) {
         lineshape = new EvtMBreitWigner( id, lsarg );
@@ -219,7 +219,7 @@
 
     while ( amp_iter != amp_end ) {
         const char* nptr;
-        char* endptr = NULL;
+        char* endptr = nullptr;
         double amp = 0.0, phase = 0.0;
 
         nptr = ( *amp_iter ).c_str();
diff --git a/src/EvtGenBase/EvtModel.cpp b/src/EvtGenBase/EvtModel.cpp
--- a/src/EvtGenBase/EvtModel.cpp
+++ b/src/EvtGenBase/EvtModel.cpp
@@ -38,7 +38,7 @@
 #include <string>
 using std::fstream;
 
-EvtModel* EvtModel::_instance = 0;
+EvtModel* EvtModel::_instance = nullptr;
 
 EvtModel::EvtModel()
 {
@@ -46,15 +46,15 @@
 
 EvtDecayBase* EvtModel::getFcn( std::string model_name )
 {
-    EvtDecayBase* model = 0;
+    EvtDecayBase* model = nullptr;
     if ( _modelNameHash.find( model_name ) != _modelNameHash.end() ) {
         model = _modelNameHash[model_name];
     }
 
-    if ( model == 0 ) {
+    if ( model == nullptr ) {
         EvtGenReport( EVTGEN_ERROR, "EvtGen" )
             << "Did not find the right model:" << model_name.c_str() << "\n";
-        return 0;
+        return nullptr;
     }
 
     return model->clone();
@@ -91,7 +91,7 @@
 
 void EvtModel::storeCommand( std::string cmd, std::string cnfgstr )
 {
-    EvtDecayBase* model = 0;
+    EvtDecayBase* model = nullptr;
     if ( _commandNameHash.find( cmd ) != _commandNameHash.end() ) {
         model = _commandNameHash[cmd];
     }
diff --git a/src/EvtGenBase/EvtMultiChannelParser.cpp b/src/EvtGenBase/EvtMultiChannelParser.cpp
--- a/src/EvtGenBase/EvtMultiChannelParser.cpp
+++ b/src/EvtGenBase/EvtMultiChannelParser.cpp
@@ -121,7 +121,7 @@
 void EvtMultiChannelParser::parse( const std::vector<std::string>& v )
 {
     // place holder for strtod
-    char** tc = 0;
+    char** tc = nullptr;
 
     // Get PDF maximum or number of points to
     // use in the scan.
@@ -200,7 +200,7 @@
                                               EvtComplex& c, int& format )
 {
     // place holder for strtod
-    char** tc = 0;
+    char** tc = nullptr;
 
     std::string coefString = v[i++];
     assert( coefString == std::string( "COEFFICIENT" ) );
@@ -233,7 +233,7 @@
                                              const std::vector<std::string>& v )
 {
     // place holder for strtod
-    char** tc = 0;
+    char** tc = nullptr;
     double value = 0;
 
     if ( v[i] == std::string( "COEFFICIENT" ) ) {
diff --git a/src/EvtGenBase/EvtParser.cpp b/src/EvtGenBase/EvtParser.cpp
--- a/src/EvtGenBase/EvtParser.cpp
+++ b/src/EvtGenBase/EvtParser.cpp
@@ -34,8 +34,8 @@
 {
     _ntoken = 0;
     _lengthoftokenlist = 0;
-    _tokenlist = 0;
-    _linelist = 0;
+    _tokenlist = nullptr;
+    _linelist = nullptr;
 }
 
 EvtParser::~EvtParser()
diff --git a/src/EvtGenBase/EvtParticle.cpp b/src/EvtGenBase/EvtParticle.cpp
--- a/src/EvtGenBase/EvtParticle.cpp
+++ b/src/EvtGenBase/EvtParticle.cpp
@@ -60,7 +60,7 @@
 EvtParticle::EvtParticle()
 {
     _ndaug = 0;
-    _parent = 0;
+    _parent = nullptr;
     _channel = -10;
     _t = 0.0;
     _genlifetime = 1;
@@ -68,7 +68,7 @@
     _isInit = false;
     _validP4 = false;
     _isDecayed = false;
-    _decayProb = 0;
+    _decayProb = nullptr;
     _intAttributes.clear();
     _dblAttributes.clear();
     //   _mix=false;
@@ -248,7 +248,7 @@
     // carefull - the parent mass might be fixed in stone..
     EvtParticle* par = p->getParent();
     double parMass = -1.;
-    if ( par != 0 ) {
+    if ( par != nullptr ) {
         if ( par->hasValidP4() )
             parMass = par->mass();
         for ( size_t i = 0; i < par->getNDaug(); i++ ) {
@@ -271,8 +271,8 @@
             }
         }
 
-        EvtId* dauId = 0;
-        double* dauMasses = 0;
+        EvtId* dauId = nullptr;
+        double* dauMasses = nullptr;
         if ( _ndaug > 0 ) {
             dauId = new EvtId[_ndaug];
             dauMasses = new double[_ndaug];
@@ -281,8 +281,8 @@
                 dauMasses[j] = p->getDaug( j )->mass();
             }
         }
-        EvtId* parId = 0;
-        EvtId* othDauId = 0;
+        EvtId* parId = nullptr;
+        EvtId* othDauId = nullptr;
         EvtParticle* tempPar = p->getParent();
         if ( tempPar ) {
             parId = new EvtId( tempPar->getId() );
@@ -391,8 +391,8 @@
     }
 
     int j;
-    EvtId* dauId = 0;
-    double* dauMasses = 0;
+    EvtId* dauId = nullptr;
+    double* dauMasses = nullptr;
     int nDaugT = p->getNDaug();
     if ( nDaugT > 0 ) {
         dauId = new EvtId[nDaugT];
@@ -403,8 +403,8 @@
         }
     }
 
-    EvtId* parId = 0;
-    EvtId* othDauId = 0;
+    EvtId* parId = nullptr;
+    EvtId* othDauId = nullptr;
     EvtParticle* tempPar = p->getParent();
     if ( tempPar ) {
         parId = new EvtId( tempPar->getId() );
@@ -496,7 +496,7 @@
         decayer = EvtDecayTable::getInstance()->getDecayFunc( p );
     }
     //now we have accepted a set of masses - time
-    if ( decayer != 0 ) {
+    if ( decayer != nullptr ) {
         decayer->makeDecay( p );
     } else {
         p->_rhoBackward.setDiag( p->getSpinStates() );
@@ -564,7 +564,7 @@
     }
 
     int nDaug = p->getNDaug();
-    double* dMasses = 0;
+    double* dMasses = nullptr;
 
     int i;
     if ( nDaug > 0 ) {
@@ -761,7 +761,7 @@
     temp = this->getP4();
     ptemp = this;
 
-    while ( ptemp->getParent() != 0 ) {
+    while ( ptemp->getParent() != nullptr ) {
         ptemp = ptemp->getParent();
         mom = ptemp->getP4();
         temp = boostTo( temp, mom );
@@ -777,7 +777,7 @@
     temp = this->_pBeforeFSR;
     ptemp = this;
 
-    while ( ptemp->getParent() != 0 ) {
+    while ( ptemp->getParent() != nullptr ) {
         ptemp = ptemp->getParent();
         mom = ptemp->getP4();
         temp = boostTo( temp, mom );
@@ -798,12 +798,12 @@
     temp.set( 0.0, 0.0, 0.0, 0.0 );
     ptemp = getParent();
 
-    if ( ptemp == 0 )
+    if ( ptemp == nullptr )
         return temp;
 
     temp = ( ptemp->_t / ptemp->mass() ) * ( ptemp->getP4() );
 
-    while ( ptemp->getParent() != 0 ) {
+    while ( ptemp->getParent() != nullptr ) {
         ptemp = ptemp->getParent();
         mom = ptemp->getP4();
         temp = boostTo( temp, mom );
@@ -826,8 +826,8 @@
 
     do {
         bpart = current->_parent;
-        if ( bpart == 0 )
-            return 0;
+        if ( bpart == nullptr )
+            return nullptr;
         i = 0;
         while ( bpart->_daug[i] != current ) {
             i++;
@@ -835,7 +835,7 @@
 
         if ( bpart == rootOfTree ) {
             if ( i + 1 == bpart->_ndaug )
-                return 0;
+                return nullptr;
         }
 
         i++;
@@ -1270,7 +1270,7 @@
 
 void EvtParticle::setDecayProb( double prob )
 {
-    if ( _decayProb == 0 )
+    if ( _decayProb == nullptr )
         _decayProb = new double;
     *_decayProb = prob;
 }
diff --git a/src/EvtGenBase/EvtParticleDecay.cpp b/src/EvtGenBase/EvtParticleDecay.cpp
--- a/src/EvtGenBase/EvtParticleDecay.cpp
+++ b/src/EvtGenBase/EvtParticleDecay.cpp
@@ -36,7 +36,7 @@
 using std::fstream;
 void EvtParticleDecay::printSummary()
 {
-    if ( _decay != 0 )
+    if ( _decay != nullptr )
         _decay->printSummary();
 }
 
diff --git a/src/EvtGenBase/EvtParticleDecayList.cpp b/src/EvtGenBase/EvtParticleDecayList.cpp
--- a/src/EvtGenBase/EvtParticleDecayList.cpp
+++ b/src/EvtGenBase/EvtParticleDecayList.cpp
@@ -79,7 +79,7 @@
         delete _decaylist[i];
     }
 
-    if ( _decaylist != 0 )
+    if ( _decaylist != nullptr )
         delete[] _decaylist;
 }
 
@@ -99,17 +99,17 @@
     }
 
     delete[] _decaylist;
-    _decaylist = 0;
+    _decaylist = nullptr;
     _nmode = 0;
     _rawbrfrsum = 0.0;
 }
 
 EvtDecayBase* EvtParticleDecayList::getDecayModel( int imode )
 {
-    EvtDecayBase* theModel( 0 );
+    EvtDecayBase* theModel( nullptr );
     if ( imode >= 0 && imode < _nmode ) {
         EvtParticleDecay* theDecay = _decaylist[imode];
-        if ( theDecay != 0 ) {
+        if ( theDecay != nullptr ) {
             theModel = theDecay->getDecayModel();
         }
     }
@@ -128,10 +128,10 @@
     }
 
     if ( getNMode() == 0 ) {
-        return 0;
+        return nullptr;
     }
     if ( getRawBrfrSum() < 0.00000001 ) {
-        return 0;
+        return nullptr;
     }
 
     if ( getNMode() == 1 ) {
@@ -208,7 +208,7 @@
         << " with mass:" << p->mass() << " will throw event away! " << endl;
 
     EvtStatus::setRejectFlag();
-    return 0;
+    return nullptr;
 }
 
 void EvtParticleDecayList::setNMode( int nmode )
@@ -220,7 +220,7 @@
             << "Error _nmode not equal to zero!!!" << endl;
         ::abort();
     }
-    if ( _decaylist != 0 ) {
+    if ( _decaylist != nullptr ) {
         delete[] _decaylist;
     }
     _decaylist = _decaylist_new;
@@ -304,7 +304,7 @@
         delete[] _decaylist;
     }
 
-    if ( ( _nmode == 0 ) && ( _decaylist != 0 ) )
+    if ( ( _nmode == 0 ) && ( _decaylist != nullptr ) )
         delete[] _decaylist;
 
     _nmode++;
diff --git a/src/EvtGenBase/EvtParticleFactory.cpp b/src/EvtGenBase/EvtParticleFactory.cpp
--- a/src/EvtGenBase/EvtParticleFactory.cpp
+++ b/src/EvtGenBase/EvtParticleFactory.cpp
@@ -91,7 +91,7 @@
 
     ::abort();
 
-    return 0;
+    return nullptr;
 }
 
 EvtParticle* EvtParticleFactory::particleFactory( EvtId id, EvtVector4R p4,
@@ -195,7 +195,7 @@
 
     ::abort();
 
-    return 0;
+    return nullptr;
 }
 
 EvtParticle* EvtParticleFactory::particleFactory( EvtId id, EvtVector4R p4 )
diff --git a/src/EvtGenBase/EvtPto3PAmp.cpp b/src/EvtGenBase/EvtPto3PAmp.cpp
--- a/src/EvtGenBase/EvtPto3PAmp.cpp
+++ b/src/EvtGenBase/EvtPto3PAmp.cpp
@@ -59,7 +59,7 @@
     _pairRes( other._pairRes ),
     _spin( other._spin ),
     _typeN( other._typeN ),
-    _prop( ( other._prop ) ? (EvtPropagator*)other._prop->clone() : 0 ),
+    _prop( ( other._prop ) ? (EvtPropagator*)other._prop->clone() : nullptr ),
     _g0( other._g0 ),
     _min( other._min ),
     _max( other._max ),
diff --git a/src/EvtGenBase/EvtPto3PAmpFactory.cpp b/src/EvtGenBase/EvtPto3PAmpFactory.cpp
--- a/src/EvtGenBase/EvtPto3PAmpFactory.cpp
+++ b/src/EvtGenBase/EvtPto3PAmpFactory.cpp
@@ -79,7 +79,7 @@
         } else if ( vv[0] == "NONRES_EXP" ) {
             typeNRes = EvtPto3PAmp::NONRES_EXP;
             pairRes = strToPair( vv[1].c_str() );
-            alpha = strtod( vv[2].c_str(), 0 );
+            alpha = strtod( vv[2].c_str(), nullptr );
         } else
             assert( 0 );
         pdf = std::make_unique<EvtDalitzFlatPdf>( _dp );
@@ -88,11 +88,11 @@
     } else if ( vv[0] == "LASS" || vv[0] == "LASS_ELASTIC" ||
                 vv[0] == "LASS_RESONANT" ) {
         pairRes = strToPair( vv[1].c_str() );
-        double m0 = strtod( vv[2].c_str(), 0 );
-        double g0 = strtod( vv[3].c_str(), 0 );
-        double a = strtod( vv[4].c_str(), 0 );
-        double r = strtod( vv[5].c_str(), 0 );
-        double cutoff = strtod( vv[6].c_str(), 0 );
+        double m0 = strtod( vv[2].c_str(), nullptr );
+        double g0 = strtod( vv[3].c_str(), nullptr );
+        double a = strtod( vv[4].c_str(), nullptr );
+        double r = strtod( vv[5].c_str(), nullptr );
+        double cutoff = strtod( vv[6].c_str(), nullptr );
         pdf = std::make_unique<EvtDalitzResPdf>( _dp, m0, g0, pairRes );
         amp = std::make_unique<EvtLASSAmp>( &_dp, pairRes, m0, g0, a, r, cutoff,
                                             vv[0] );
@@ -146,8 +146,8 @@
                 }
             }
 
-            mR = strtod( vv[3].c_str(), 0 );
-            gR = strtod( vv[4].c_str(), 0 );
+            mR = strtod( vv[3].c_str(), nullptr );
+            gR = strtod( vv[4].c_str(), nullptr );
             i = 4;
         } else {
             // For a valid particle get spin, mass and width
@@ -165,8 +165,8 @@
                     printf( "Setting m(%s)=%s g(%s)=%s\n", vv[2].c_str(),
                             vv[3].c_str(), vv[2].c_str(), vv[4].c_str() );
 
-                mR = strtod( vv[3].c_str(), 0 );
-                gR = strtod( vv[4].c_str(), 0 );
+                mR = strtod( vv[3].c_str(), nullptr );
+                gR = strtod( vv[4].c_str(), nullptr );
                 i = 4;
             }
         }
@@ -212,9 +212,9 @@
             double m1a = _dp.m( first( pairRes ) );
             double m1b = _dp.m( second( pairRes ) );
             // 2nd channel
-            double g2 = strtod( vv[++i].c_str(), 0 );
-            double m2a = strtod( vv[++i].c_str(), 0 );
-            double m2b = strtod( vv[++i].c_str(), 0 );
+            double g2 = strtod( vv[++i].c_str(), nullptr );
+            double m2a = strtod( vv[++i].c_str(), nullptr );
+            double m2b = strtod( vv[++i].c_str(), nullptr );
             EvtPropFlatte prop( mR, gR, m1a, m1b, g2, m2a, m2b );
             partAmp = std::make_unique<EvtPto3PAmp>( _dp, pairAng, pairRes, spinR,
                                                      prop, EvtPto3PAmp::FLATTE );
@@ -227,7 +227,7 @@
             if ( vv[i + 1] == "DVFF" ) {
                 i++;
                 if ( vv[++i] == "BLATTWEISSKOPF" ) {
-                    double R = strtod( vv[++i].c_str(), 0 );
+                    double R = strtod( vv[++i].c_str(), nullptr );
                     partAmp->set_fd( R );
                 } else
                     assert( 0 );
@@ -240,7 +240,7 @@
                 if ( vv[++i] == "BLATTWEISSKOPF" ) {
                     if ( _verbose )
                         printf( "BVFF=%s\n", vv[i].c_str() );
-                    double R = strtod( vv[++i].c_str(), 0 );
+                    double R = strtod( vv[++i].c_str(), nullptr );
                     partAmp->set_fb( R );
                 } else
                     assert( 0 );
@@ -254,7 +254,7 @@
                 i++;
                 if ( vv[i + 1] == "MIN" ) {
                     i++;
-                    double min = strtod( vv[++i].c_str(), 0 );
+                    double min = strtod( vv[++i].c_str(), nullptr );
                     if ( _verbose )
                         std::cout << "CUTOFF MIN = " << min << " " << minwidths
                                   << std::endl;
@@ -263,7 +263,7 @@
                     partAmp->setmin( min );
                 } else if ( vv[i + 1] == "MAX" ) {
                     i++;
-                    double max = strtod( vv[++i].c_str(), 0 );
+                    double max = strtod( vv[++i].c_str(), nullptr );
                     if ( _verbose )
                         std::cout << "CUTOFF MAX = " << max << " " << minwidths
                                   << std::endl;
@@ -281,7 +281,7 @@
                 i++;
                 if ( vv[i + 1] == "MIN" ) {
                     i++;
-                    double min = strtod( vv[++i].c_str(), 0 );
+                    double min = strtod( vv[++i].c_str(), nullptr );
                     if ( _verbose )
                         std::cout << "CUTOFF MIN = " << min << std::endl;
                     //ensure against cutting off too close to the resonance
@@ -289,7 +289,7 @@
                     partAmp->setmin( min );
                 } else if ( vv[i + 1] == "MAX" ) {
                     i++;
-                    double max = strtod( vv[++i].c_str(), 0 );
+                    double max = strtod( vv[++i].c_str(), nullptr );
                     if ( _verbose )
                         std::cout << "CUTOFF MAX = " << max << std::endl;
                     //ensure against cutting off too close to the resonance
diff --git a/src/EvtGenBase/EvtRadCorr.cpp b/src/EvtGenBase/EvtRadCorr.cpp
--- a/src/EvtGenBase/EvtRadCorr.cpp
+++ b/src/EvtGenBase/EvtRadCorr.cpp
@@ -28,13 +28,13 @@
 #include <stdlib.h>
 using std::endl;
 
-EvtAbsRadCorr* EvtRadCorr::_fsrEngine = 0;
+EvtAbsRadCorr* EvtRadCorr::_fsrEngine = nullptr;
 bool EvtRadCorr::_alwaysRadCorr = false;
 bool EvtRadCorr::_neverRadCorr = false;
 
 EvtRadCorr::EvtRadCorr()
 {
-    _fsrEngine = 0;
+    _fsrEngine = nullptr;
     _alwaysRadCorr = false;
     _neverRadCorr = false;
 }
@@ -43,7 +43,7 @@
 {
     if ( _fsrEngine )
         delete _fsrEngine;
-    _fsrEngine = 0;
+    _fsrEngine = nullptr;
 }
 
 void EvtRadCorr::setRadCorrEngine( EvtAbsRadCorr* fsrEngine )
@@ -53,7 +53,7 @@
 
 void EvtRadCorr::doRadCorr( EvtParticle* p )
 {
-    if ( _fsrEngine == 0 ) {
+    if ( _fsrEngine == nullptr ) {
         EvtGenReport( EVTGEN_ERROR, "EvtGen" )
             << "No RadCorr model available in "
             << "EvtRadCorr::doRadCorr()." << endl;
diff --git a/src/EvtGenBase/EvtRandom.cpp b/src/EvtGenBase/EvtRandom.cpp
--- a/src/EvtGenBase/EvtRandom.cpp
+++ b/src/EvtGenBase/EvtRandom.cpp
@@ -32,7 +32,7 @@
 
 using std::endl;
 
-EvtRandomEngine* EvtRandom::_randomEngine = 0;
+EvtRandomEngine* EvtRandom::_randomEngine = nullptr;
 
 void EvtRandom::setRandomEngine( EvtRandomEngine* randomEngine )
 {
@@ -41,7 +41,7 @@
 
 double EvtRandom::random()
 {
-    if ( _randomEngine == 0 ) {
+    if ( _randomEngine == nullptr ) {
         EvtGenReport( EVTGEN_ERROR, "EvtGen" )
             << "No random engine available in "
             << "EvtRandom::random()." << endl;
diff --git a/src/EvtGenBase/EvtReport.cpp b/src/EvtGenBase/EvtReport.cpp
--- a/src/EvtGenBase/EvtReport.cpp
+++ b/src/EvtGenBase/EvtReport.cpp
@@ -34,7 +34,7 @@
 {
     int printNoFacility = 1;
 
-    if ( ( facility == 0 ) && ( printNoFacility == 1 ) ) {
+    if ( ( facility == nullptr ) && ( printNoFacility == 1 ) ) {
         cout << "There is no `facility' implemented in `report'" << endl;
         printNoFacility = 0;
     }
diff --git a/src/EvtGenBase/EvtSpinDensity.cpp b/src/EvtGenBase/EvtSpinDensity.cpp
--- a/src/EvtGenBase/EvtSpinDensity.cpp
+++ b/src/EvtGenBase/EvtSpinDensity.cpp
@@ -34,7 +34,7 @@
 EvtSpinDensity::EvtSpinDensity( const EvtSpinDensity& density )
 {
     dim = 0;
-    rho = 0;
+    rho = nullptr;
 
     int i, j;
     setDim( density.dim );
@@ -74,7 +74,7 @@
 EvtSpinDensity::EvtSpinDensity()
 {
     dim = 0;
-    rho = 0;
+    rho = nullptr;
 }
 
 void EvtSpinDensity::setDim( int n )
@@ -86,7 +86,7 @@
         for ( i = 0; i < dim; i++ )
             delete[] rho[i];
         delete[] rho;
-        rho = 0;
+        rho = nullptr;
         dim = 0;
     }
     if ( n == 0 )
diff --git a/src/EvtGenBase/EvtdFunctionSingle.cpp b/src/EvtGenBase/EvtdFunctionSingle.cpp
--- a/src/EvtGenBase/EvtdFunctionSingle.cpp
+++ b/src/EvtGenBase/EvtdFunctionSingle.cpp
@@ -32,14 +32,14 @@
     _j = 0;
     _m1 = 0;
     _m2 = 0;
-    _coef = 0;
+    _coef = nullptr;
     _kmin = 0;
     _kmax = 0;
 }
 
 EvtdFunctionSingle::~EvtdFunctionSingle()
 {
-    if ( _coef != 0 )
+    if ( _coef != nullptr )
         delete[] _coef;
 }
 
diff --git a/src/EvtGenExternal/EvtExternalGenFactory.cpp b/src/EvtGenExternal/EvtExternalGenFactory.cpp
--- a/src/EvtGenExternal/EvtExternalGenFactory.cpp
+++ b/src/EvtGenExternal/EvtExternalGenFactory.cpp
@@ -56,9 +56,9 @@
 
 EvtExternalGenFactory* EvtExternalGenFactory::getInstance()
 {
-    static EvtExternalGenFactory* theFactory = 0;
+    static EvtExternalGenFactory* theFactory = nullptr;
 
-    if ( theFactory == 0 ) {
+    if ( theFactory == nullptr ) {
         theFactory = new EvtExternalGenFactory();
     }
 
@@ -136,7 +136,7 @@
 
 EvtAbsExternalGen* EvtExternalGenFactory::getGenerator( int genId )
 {
-    EvtAbsExternalGen* theGenerator( 0 );
+    EvtAbsExternalGen* theGenerator( nullptr );
 
     ExtGenMap::iterator iter;
 
@@ -158,7 +158,7 @@
     ExtGenMap::iterator iter;
     for ( iter = _extGenMap.begin(); iter != _extGenMap.end(); ++iter ) {
         EvtAbsExternalGen* theGenerator = iter->second;
-        if ( theGenerator != 0 ) {
+        if ( theGenerator != nullptr ) {
             theGenerator->initialise();
         }
     }
diff --git a/src/EvtGenExternal/EvtExternalGenList.cpp b/src/EvtGenExternal/EvtExternalGenList.cpp
--- a/src/EvtGenExternal/EvtExternalGenList.cpp
+++ b/src/EvtGenExternal/EvtExternalGenList.cpp
@@ -41,7 +41,7 @@
         // PYTHIA8DATA environment variable which should be set to the
         // xmldoc Pythia directory
         char* pythiaDataDir = getenv( "PYTHIA8DATA" );
-        if ( pythiaDataDir != 0 ) {
+        if ( pythiaDataDir != nullptr ) {
             pythiaXmlDir = pythiaDataDir;
         }
     }
diff --git a/src/EvtGenExternal/EvtPhotosEngine.cpp b/src/EvtGenExternal/EvtPhotosEngine.cpp
--- a/src/EvtGenExternal/EvtPhotosEngine.cpp
+++ b/src/EvtGenExternal/EvtPhotosEngine.cpp
@@ -90,7 +90,7 @@
         this->initialise();
     }
 
-    if ( theMother == 0 ) {
+    if ( theMother == nullptr ) {
         return false;
     }
 
@@ -174,7 +174,7 @@
             double px( 0.0 ), py( 0.0 ), pz( 0.0 );
             int pdgId( 0 );
 
-            if ( outParticle != 0 ) {
+            if ( outParticle != nullptr ) {
                 FourVector HepMCP4 = outParticle->momentum();
                 px = HepMCP4.px();
                 py = HepMCP4.py();
@@ -188,7 +188,7 @@
             if ( iLoop < nDaug ) {
                 // Original daughters
                 EvtParticle* daugParticle = theMother->getDaug( iLoop );
-                if ( daugParticle != 0 ) {
+                if ( daugParticle != nullptr ) {
                     // Keep the original particle mass, but set the three-momentum
                     // according to what Photos has modified. However, this will
                     // violate energy conservation (from what Photos has provided).
@@ -233,8 +233,8 @@
                                                    bool incoming )
 {
     // Method to create an HepMC::GenParticle version of the given EvtParticle.
-    if ( theParticle == 0 ) {
-        return 0;
+    if ( theParticle == nullptr ) {
+        return nullptr;
     }
 
     // Get the 4-momentum (E, px, py, pz) for the EvtParticle
@@ -291,7 +291,7 @@
 
         // Get the PDG id
         int pdgId( 0 );
-        if ( outParticle != 0 ) {
+        if ( outParticle != nullptr ) {
             pdgId = outParticle->pdg_id();
         }
 
diff --git a/src/EvtGenExternal/EvtPythia.cpp b/src/EvtGenExternal/EvtPythia.cpp
--- a/src/EvtGenExternal/EvtPythia.cpp
+++ b/src/EvtGenExternal/EvtPythia.cpp
@@ -39,7 +39,7 @@
     // Set the Pythia engine to a null pointer at first.
     // When we do the decay, we retrieve the pointer to the Pythia engine
     // and use that for all decays. All clones will use the same Pythia engine.
-    _pythiaEngine = 0;
+    _pythiaEngine = nullptr;
 }
 
 EvtPythia::~EvtPythia()
diff --git a/src/EvtGenExternal/EvtPythiaEngine.cpp b/src/EvtGenExternal/EvtPythiaEngine.cpp
--- a/src/EvtGenExternal/EvtPythiaEngine.cpp
+++ b/src/EvtGenExternal/EvtPythiaEngine.cpp
@@ -65,7 +65,7 @@
         << "Creating alias Pythia generator" << endl;
     _aliasPythiaGen = std::make_unique<Pythia8::Pythia>( xmlDir, false );
 
-    _thePythiaGenerator = 0;
+    _thePythiaGenerator = nullptr;
     _daugPDGVector.clear();
     _daugP4Vector.clear();
 
@@ -159,7 +159,7 @@
         this->initialise();
     }
 
-    if ( theParticle == 0 ) {
+    if ( theParticle == nullptr ) {
         EvtGenReport( EVTGEN_INFO, "EvtGen" )
             << "Error in EvtPythiaEngine::doDecay. The mother particle is null. Not doing any Pythia decay."
             << endl;
@@ -286,7 +286,7 @@
 
 void EvtPythiaEngine::createDaughterEvtParticles( EvtParticle* theParent )
 {
-    if ( theParent == 0 ) {
+    if ( theParent == nullptr ) {
         EvtGenReport( EVTGEN_INFO, "EvtGen" )
             << "Error in EvtPythiaEngine::createDaughterEvtParticles. The parent is null"
             << endl;
@@ -334,7 +334,7 @@
         EvtDecayBase* decayModel = EvtDecayTable::getInstance()->findDecayModel(
             aliasInt, pythiaModeInt );
 
-        if ( decayModel != 0 ) {
+        if ( decayModel != nullptr ) {
             int nModeDaug = decayModel->getNDaug();
 
             // We need to make sure that the number of daughters match
@@ -389,7 +389,7 @@
         EvtParticle* theDaughter = theParent->getDaug( iDaug );
 
         // Set the correct 4-momentum for each daughter particle.
-        if ( theDaughter != 0 ) {
+        if ( theDaughter != nullptr ) {
             EvtId theDaugId = daugAliasIdVect[iDaug];
             const EvtVector4R theDaugP4 = _daugP4Vector[iDaug];
             theDaughter->init( theDaugId, theDaugP4 );
@@ -443,7 +443,7 @@
 
         // Check that the PDG code is not zero/null and exclude other
         // special cases, e.g. those reserved for internal generator use
-        if ( entry_generic != 0 && this->validPDGCode( PDGCode ) ) {
+        if ( entry_generic != nullptr && this->validPDGCode( PDGCode ) ) {
             entry_generic->setM0( mass );
             entry_generic->setMWidth( width );
             entry_generic->setTau0( lifetime );
@@ -456,7 +456,7 @@
 
         // Check that the PDG code is not zero/null and exclude other
         // special cases, e.g. those reserved for internal generator use
-        if ( entry_alias != 0 && this->validPDGCode( PDGCode ) ) {
+        if ( entry_alias != nullptr && this->validPDGCode( PDGCode ) ) {
             entry_alias->setM0( mass );
             entry_alias->setMWidth( width );
             entry_alias->setTau0( lifetime );
@@ -557,7 +557,7 @@
         EvtDecayBase* decayModel =
             EvtDecayTable::getInstance()->findDecayModel( aliasInt, iMode );
 
-        if ( decayModel != 0 ) {
+        if ( decayModel != nullptr ) {
             int nDaug = decayModel->getNDaug();
 
             // If the decay mode has no daughters, then that means that there will be
@@ -645,7 +645,7 @@
 {
     int tmpModeInt( 0 ), modeInt( 0 );
 
-    if ( decayModel != 0 ) {
+    if ( decayModel != nullptr ) {
         int nVars = decayModel->getNArg();
         // Just read the first integer, which specifies the Pythia decay model.
         // Ignore any other values.
diff --git a/src/EvtGenExternal/EvtTauolaEngine.cpp b/src/EvtGenExternal/EvtTauolaEngine.cpp
--- a/src/EvtGenExternal/EvtTauolaEngine.cpp
+++ b/src/EvtGenExternal/EvtTauolaEngine.cpp
@@ -326,7 +326,7 @@
         this->initialise();
     }
 
-    if ( tauParticle == 0 ) {
+    if ( tauParticle == nullptr ) {
         return false;
     }
 
@@ -369,7 +369,7 @@
 
     // Get the parent of this tau particle
     EvtParticle* theParent = tauParticle->getParent();
-    GenParticlePtr hepMCParent( 0 );
+    GenParticlePtr hepMCParent( nullptr );
 
     // Assign the parent particle as the incoming particle to the vertex.
     if ( theParent ) {
@@ -573,8 +573,8 @@
 GenParticlePtr EvtTauolaEngine::createGenParticle( EvtParticle* theParticle )
 {
     // Method to create an HepMC::GenParticle version of the given EvtParticle.
-    if ( theParticle == 0 ) {
-        return 0;
+    if ( theParticle == nullptr ) {
+        return nullptr;
     }
 
     // Get the 4-momentum (E, px, py, pz) for the EvtParticle
diff --git a/src/EvtGenModels/EvtBtoXsgamma.cpp b/src/EvtGenModels/EvtBtoXsgamma.cpp
--- a/src/EvtGenModels/EvtBtoXsgamma.cpp
+++ b/src/EvtGenModels/EvtBtoXsgamma.cpp
@@ -75,7 +75,7 @@
 {
     //initialize here. -- its too damn slow otherwise.
 
-    if ( _model == 0 ) {
+    if ( _model == nullptr ) {
         if ( getArg( 0 ) == 1 )
             _model = std::make_unique<EvtBtoXsgammaAliGreub>();
         else if ( getArg( 0 ) == 2 )
diff --git a/src/EvtGenModels/EvtD0gammaDalitz.cpp b/src/EvtGenModels/EvtD0gammaDalitz.cpp
--- a/src/EvtGenModels/EvtD0gammaDalitz.cpp
+++ b/src/EvtGenModels/EvtD0gammaDalitz.cpp
@@ -118,7 +118,7 @@
     // Check if the D is from a B+- -> D0 K+- decay with the appropriate model.
     EvtParticle* parent =
         part->getParent();    // If there are no mistakes, should be B+ or B-.
-    if ( parent != 0 &&
+    if ( parent != nullptr &&
          EvtDecayTable::getInstance()->getDecayFunc( parent )->getName() ==
              "BTODDALITZCPK" ) {
         EvtId parId = parent->getId();
diff --git a/src/EvtGenModels/EvtDalitzTable.cpp b/src/EvtGenModels/EvtDalitzTable.cpp
--- a/src/EvtGenModels/EvtDalitzTable.cpp
+++ b/src/EvtGenModels/EvtDalitzTable.cpp
@@ -49,9 +49,9 @@
 EvtDalitzTable* EvtDalitzTable::getInstance( const std::string dec_name,
                                              bool verbose )
 {
-    static EvtDalitzTable* theDalitzTable = 0;
+    static EvtDalitzTable* theDalitzTable = nullptr;
 
-    if ( theDalitzTable == 0 ) {
+    if ( theDalitzTable == nullptr ) {
         theDalitzTable = new EvtDalitzTable();
     }
 
@@ -83,7 +83,7 @@
 
     _readFiles.push_back( dec_name );
 
-    EvtDalitzDecayInfo* dalitzDecay = 0;
+    EvtDalitzDecayInfo* dalitzDecay = nullptr;
     double probMax = 0;
     EvtId ipar;
     std::string decayParent = "";
@@ -385,7 +385,7 @@
                 dalitzDecay->setProbMax( probMax );
                 addDecay( ipar, *dalitzDecay );
                 delete dalitzDecay;
-                dalitzDecay = 0;
+                dalitzDecay = nullptr;
             } else if ( verbose ) {
                 EvtGenReport( EVTGEN_INFO, "EvtGen" )
                     << "Unexpected tag " << parser.getTagTitle()
diff --git a/src/EvtGenModels/EvtLb2Baryonlnu.cpp b/src/EvtGenModels/EvtLb2Baryonlnu.cpp
--- a/src/EvtGenModels/EvtLb2Baryonlnu.cpp
+++ b/src/EvtGenModels/EvtLb2Baryonlnu.cpp
@@ -37,16 +37,16 @@
 #ifdef D0
 #undef D0
 #endif
-EvtLb2Baryonlnu::EvtLb2Baryonlnu() : ffmodel( 0 ), calcamp( 0 )
+EvtLb2Baryonlnu::EvtLb2Baryonlnu() : ffmodel( nullptr ), calcamp( nullptr )
 {
 }
 
 EvtLb2Baryonlnu::~EvtLb2Baryonlnu()
 {
     delete ffmodel;
-    ffmodel = 0;
+    ffmodel = nullptr;
     delete calcamp;
-    calcamp = 0;
+    calcamp = nullptr;
 }
 
 std::string EvtLb2Baryonlnu::getName()
diff --git a/src/EvtGenModels/EvtLb2plnuLCSR.cpp b/src/EvtGenModels/EvtLb2plnuLCSR.cpp
--- a/src/EvtGenModels/EvtLb2plnuLCSR.cpp
+++ b/src/EvtGenModels/EvtLb2plnuLCSR.cpp
@@ -37,16 +37,16 @@
 #ifdef D0
 #undef D0
 #endif
-EvtLb2plnuLCSR::EvtLb2plnuLCSR() : ffmodel( 0 ), calcamp( 0 )
+EvtLb2plnuLCSR::EvtLb2plnuLCSR() : ffmodel( nullptr ), calcamp( nullptr )
 {
 }
 
 EvtLb2plnuLCSR::~EvtLb2plnuLCSR()
 {
     delete ffmodel;
-    ffmodel = 0;
+    ffmodel = nullptr;
     delete calcamp;
-    calcamp = 0;
+    calcamp = nullptr;
 }
 
 std::string EvtLb2plnuLCSR::getName()
diff --git a/src/EvtGenModels/EvtLb2plnuLQCD.cpp b/src/EvtGenModels/EvtLb2plnuLQCD.cpp
--- a/src/EvtGenModels/EvtLb2plnuLQCD.cpp
+++ b/src/EvtGenModels/EvtLb2plnuLQCD.cpp
@@ -37,16 +37,16 @@
 #ifdef D0
 #undef D0
 #endif
-EvtLb2plnuLQCD::EvtLb2plnuLQCD() : ffmodel( 0 ), calcamp( 0 )
+EvtLb2plnuLQCD::EvtLb2plnuLQCD() : ffmodel( nullptr ), calcamp( nullptr )
 {
 }
 
 EvtLb2plnuLQCD::~EvtLb2plnuLQCD()
 {
     delete ffmodel;
-    ffmodel = 0;
+    ffmodel = nullptr;
     delete calcamp;
-    calcamp = 0;
+    calcamp = nullptr;
 }
 
 std::string EvtLb2plnuLQCD::getName()
diff --git a/src/EvtGenModels/EvtMultibody.cpp b/src/EvtGenModels/EvtMultibody.cpp
--- a/src/EvtGenModels/EvtMultibody.cpp
+++ b/src/EvtGenModels/EvtMultibody.cpp
@@ -33,12 +33,12 @@
 
 EvtMultibody::~EvtMultibody()
 {
-    if ( _decayTree != NULL )
+    if ( _decayTree != nullptr )
         delete _decayTree;
-    _decayTree = NULL;
-    if ( _ilist != NULL )
+    _decayTree = nullptr;
+    if ( _ilist != nullptr )
         delete[] _ilist;
-    _ilist = NULL;
+    _ilist = nullptr;
 }
 
 std::string EvtMultibody::getName()
diff --git a/src/EvtGenModels/EvtPropSLPole.cpp b/src/EvtGenModels/EvtPropSLPole.cpp
--- a/src/EvtGenModels/EvtPropSLPole.cpp
+++ b/src/EvtGenModels/EvtPropSLPole.cpp
@@ -200,7 +200,7 @@
 
     EvtParticle* par = pmeson->getParent();
     double maxMass = -1.;
-    if ( par != 0 ) {
+    if ( par != nullptr ) {
         if ( par->hasValidP4() )
             maxMass = par->mass();
         for ( size_t i = 0; i < par->getNDaug(); i++ ) {
@@ -210,8 +210,8 @@
         }
     }
 
-    EvtId* dauId = 0;
-    double* dauMasses = 0;
+    EvtId* dauId = nullptr;
+    double* dauMasses = nullptr;
     size_t nDaug = pmeson->getNDaug();
     if ( nDaug > 0 ) {
         dauId = new EvtId[nDaug];
@@ -221,8 +221,8 @@
             dauMasses[j] = pmeson->getDaug( j )->mass();
         }
     }
-    EvtId* parId = 0;
-    EvtId* othDaugId = 0;
+    EvtId* parId = nullptr;
+    EvtId* othDaugId = nullptr;
     EvtParticle* tempPar = pmeson->getParent();
     if ( tempPar ) {
         parId = new EvtId( tempPar->getId() );
diff --git a/src/EvtGenModels/EvtRareLbToLll.cpp b/src/EvtGenModels/EvtRareLbToLll.cpp
--- a/src/EvtGenModels/EvtRareLbToLll.cpp
+++ b/src/EvtGenModels/EvtRareLbToLll.cpp
@@ -229,8 +229,8 @@
 
     const bool isparticle = isParticle( parent );
 
-    const EvtParticle* lp = 0;
-    const EvtParticle* lm = 0;
+    const EvtParticle* lp = nullptr;
+    const EvtParticle* lm = nullptr;
 
     if ( leptons.contains( parent.getDaug( 1 )->getId() ) ) {
         lp = parent.getDaug( 1 );
diff --git a/src/EvtGenModels/EvtVub.cpp b/src/EvtGenModels/EvtVub.cpp
--- a/src/EvtGenModels/EvtVub.cpp
+++ b/src/EvtGenModels/EvtVub.cpp
@@ -166,7 +166,7 @@
     int j;
     // B+ -> u-bar specflav l+ nu
 
-    EvtParticle *xuhad( 0 ), *lepton( 0 ), *neutrino( 0 );
+    EvtParticle *xuhad( nullptr ), *lepton( nullptr ), *neutrino( nullptr );
     EvtVector4R p4;
     // R. Faccini 21/02/03
     // move the reweighting up , before also shooting the fermi distribution
diff --git a/src/EvtGenModels/EvtVubBLNP.cpp b/src/EvtGenModels/EvtVubBLNP.cpp
--- a/src/EvtGenModels/EvtVubBLNP.cpp
+++ b/src/EvtGenModels/EvtVubBLNP.cpp
@@ -190,7 +190,7 @@
 {
     int j;
 
-    EvtParticle *xuhad( 0 ), *lepton( 0 ), *neutrino( 0 );
+    EvtParticle *xuhad( nullptr ), *lepton( nullptr ), *neutrino( nullptr );
     EvtVector4R p4;
     double Pp, Pm, Pl, pdf, EX, sh, ml, mpi, ratemax;
     double El( 0. );
diff --git a/src/EvtGenModels/EvtVubHybrid.cpp b/src/EvtGenModels/EvtVubHybrid.cpp
--- a/src/EvtGenModels/EvtVubHybrid.cpp
+++ b/src/EvtGenModels/EvtVubHybrid.cpp
@@ -162,7 +162,7 @@
     int j;
     // B+ -> u-bar specflav l+ nu
 
-    EvtParticle *xuhad( 0 ), *lepton( 0 ), *neutrino( 0 );
+    EvtParticle *xuhad( nullptr ), *lepton( nullptr ), *neutrino( nullptr );
     EvtVector4R p4;
     // R. Faccini 21/02/03
     // move the reweighting up , before also shooting the fermi distribution
diff --git a/src/EvtGenModels/EvtbTosllScalarAmpNew.cpp b/src/EvtGenModels/EvtbTosllScalarAmpNew.cpp
--- a/src/EvtGenModels/EvtbTosllScalarAmpNew.cpp
+++ b/src/EvtGenModels/EvtbTosllScalarAmpNew.cpp
@@ -294,8 +294,8 @@
     int charge1 = EvtPDL::chg3( parent->getDaug( 1 )->getId() );
     int charge2 = EvtPDL::chg3( parent->getDaug( 2 )->getId() );
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 ) ? parent->getDaug( 1 ) : parent->getDaug( 2 );
     lepMinus = ( charge1 < charge2 ) ? parent->getDaug( 1 )
diff --git a/src/EvtGenModels/EvtbTosllScalarAmpNewExt.cpp b/src/EvtGenModels/EvtbTosllScalarAmpNewExt.cpp
--- a/src/EvtGenModels/EvtbTosllScalarAmpNewExt.cpp
+++ b/src/EvtGenModels/EvtbTosllScalarAmpNewExt.cpp
@@ -291,8 +291,8 @@
     int charge1 = EvtPDL::chg3( parent->getDaug( 1 )->getId() );
     int charge2 = EvtPDL::chg3( parent->getDaug( 2 )->getId() );
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 ) ? parent->getDaug( 1 ) : parent->getDaug( 2 );
     lepMinus = ( charge1 < charge2 ) ? parent->getDaug( 1 )
diff --git a/src/EvtGenModels/EvtbTosllVectorAmp.cpp b/src/EvtGenModels/EvtbTosllVectorAmp.cpp
--- a/src/EvtGenModels/EvtbTosllVectorAmp.cpp
+++ b/src/EvtGenModels/EvtbTosllVectorAmp.cpp
@@ -131,8 +131,8 @@
     static EvtIdSet bmesons( "B-", "anti-B0", "anti-B_s0" );
     static EvtIdSet bbarmesons( "B+", "B0", "B_s0" );
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     int charge1 = EvtPDL::chg3( parent->getDaug( 1 )->getId() );
     int charge2 = EvtPDL::chg3( parent->getDaug( 2 )->getId() );
diff --git a/src/EvtGenModels/EvtbTosllVectorAmpNew.cpp b/src/EvtGenModels/EvtbTosllVectorAmpNew.cpp
--- a/src/EvtGenModels/EvtbTosllVectorAmpNew.cpp
+++ b/src/EvtGenModels/EvtbTosllVectorAmpNew.cpp
@@ -329,8 +329,8 @@
     int charge1 = EvtPDL::chg3( parent->getDaug( 1 )->getId() );
     int charge2 = EvtPDL::chg3( parent->getDaug( 2 )->getId() );
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 ) ? parent->getDaug( 1 ) : parent->getDaug( 2 );
     lepMinus = ( charge1 < charge2 ) ? parent->getDaug( 1 )
diff --git a/src/EvtGenModels/EvtbTosllVectorAmpNewExt.cpp b/src/EvtGenModels/EvtbTosllVectorAmpNewExt.cpp
--- a/src/EvtGenModels/EvtbTosllVectorAmpNewExt.cpp
+++ b/src/EvtGenModels/EvtbTosllVectorAmpNewExt.cpp
@@ -336,8 +336,8 @@
     int charge1 = EvtPDL::chg3( parent->getDaug( 1 )->getId() );
     int charge2 = EvtPDL::chg3( parent->getDaug( 2 )->getId() );
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 ) ? parent->getDaug( 1 ) : parent->getDaug( 2 );
     lepMinus = ( charge1 < charge2 ) ? parent->getDaug( 1 )
diff --git a/src/EvtGenModels/Evtbs2llGammaAmp.cpp b/src/EvtGenModels/Evtbs2llGammaAmp.cpp
--- a/src/EvtGenModels/Evtbs2llGammaAmp.cpp
+++ b/src/EvtGenModels/Evtbs2llGammaAmp.cpp
@@ -105,8 +105,8 @@
         ::abort();
     }
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 )
                   ? parent->getDaug( il1 )
diff --git a/src/EvtGenModels/Evtbs2llGammaISRFSRAmp.cpp b/src/EvtGenModels/Evtbs2llGammaISRFSRAmp.cpp
--- a/src/EvtGenModels/Evtbs2llGammaISRFSRAmp.cpp
+++ b/src/EvtGenModels/Evtbs2llGammaISRFSRAmp.cpp
@@ -110,8 +110,8 @@
         ::abort();
     }
 
-    EvtParticle* lepPlus = 0;
-    EvtParticle* lepMinus = 0;
+    EvtParticle* lepPlus = nullptr;
+    EvtParticle* lepMinus = nullptr;
 
     lepPlus = ( charge1 > charge2 )
                   ? parent->getDaug( il1 )
diff --git a/src/EvtGenModels/EvtbsToLLLLAmp.cpp b/src/EvtGenModels/EvtbsToLLLLAmp.cpp
--- a/src/EvtGenModels/EvtbsToLLLLAmp.cpp
+++ b/src/EvtGenModels/EvtbsToLLLLAmp.cpp
@@ -181,10 +181,10 @@
         ::abort();
     }
 
-    EvtParticle* lep1Plus = 0;
-    EvtParticle* lep1Minus = 0;
-    EvtParticle* lep2Plus = 0;
-    EvtParticle* lep2Minus = 0;
+    EvtParticle* lep1Plus = nullptr;
+    EvtParticle* lep1Minus = nullptr;
+    EvtParticle* lep2Plus = nullptr;
+    EvtParticle* lep2Minus = nullptr;
 
     EvtVector4R p;    // B-meson momentum in the B-rest frame
     EvtVector4R q;    // first transition 4-momentum in the B-rest frame
diff --git a/src/EvtGenModels/EvtbsToLLLLHyperCPAmp.cpp b/src/EvtGenModels/EvtbsToLLLLHyperCPAmp.cpp
--- a/src/EvtGenModels/EvtbsToLLLLHyperCPAmp.cpp
+++ b/src/EvtGenModels/EvtbsToLLLLHyperCPAmp.cpp
@@ -151,10 +151,10 @@
         ::abort();
     }
 
-    EvtParticle* lep1Plus = 0;
-    EvtParticle* lep1Minus = 0;
-    EvtParticle* lep2Plus = 0;
-    EvtParticle* lep2Minus = 0;
+    EvtParticle* lep1Plus = nullptr;
+    EvtParticle* lep1Minus = nullptr;
+    EvtParticle* lep2Plus = nullptr;
+    EvtParticle* lep2Minus = nullptr;
 
     EvtVector4R p;    // B-meson momentum in the B-rest frame
 
diff --git a/test/evt_dalitz.cc b/test/evt_dalitz.cc
--- a/test/evt_dalitz.cc
+++ b/test/evt_dalitz.cc
@@ -89,7 +89,7 @@
     // Initialize EvtGen
 
     // Define the random number generator
-    EvtRandomEngine* eng = 0;
+    EvtRandomEngine* eng = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -100,7 +100,7 @@
 
     EvtRandom::setRandomEngine( eng );
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
diff --git a/test/evtgenlhc_test1.cc b/test/evtgenlhc_test1.cc
--- a/test/evtgenlhc_test1.cc
+++ b/test/evtgenlhc_test1.cc
@@ -150,12 +150,12 @@
 void runDDK( int nevent, EvtGen& myGenerator );
 void runPhspDecaytimeCut( int nevent, EvtGen& myGenerator );
 
-int countInclusive( std::string name, EvtParticle* root, TH1F* mom = 0,
-                    TH1F* mass = 0 );
+int countInclusive( std::string name, EvtParticle* root, TH1F* mom = nullptr,
+                    TH1F* mass = nullptr );
 int countInclusiveParent( std::string name, EvtParticle* root, EvtIdSet setIds,
-                          TH1F* mom = 0 );
+                          TH1F* mom = nullptr );
 int countInclusiveSubTree( std::string name, EvtParticle* root, EvtIdSet setIds,
-                           TH1F* mom = 0 );
+                           TH1F* mom = nullptr );
 void runBaryonic( int nEvent, EvtGen& myGenerator );
 void run3BPhspRegion( int nEvent, EvtGen& myGenerator );
 void runFourBody( int nevent, EvtGen& myGenerator );
@@ -163,7 +163,7 @@
 int main( int argc, char* argv[] )
 {
     // Define the random number generator
-    EvtRandomEngine* myRandomEngine = 0;
+    EvtRandomEngine* myRandomEngine = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -190,7 +190,7 @@
         return 1;
     }
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
@@ -690,7 +690,7 @@
                 }
             }
             p = p->nextIter( root_part );
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         root_part->deleteTree();
     } while ( count++ < nevent );
@@ -904,7 +904,7 @@
             if ( theKs.contains( type ) && theBs.contains( typePar ) )
                 nK++;
             p = p->nextIter( theB01 );
-        } while ( p != 0 );
+        } while ( p != nullptr );
         if ( nD == 2 && nK == 1 )
             nDDK++;
 
@@ -920,7 +920,7 @@
             if ( theKs.contains( type ) && theBs.contains( typePar ) )
                 nK++;
             p = p->nextIter( theB02 );
-        } while ( p != 0 );
+        } while ( p != nullptr );
         if ( nD == 2 && nK == 1 )
             nDDK++;
 
@@ -1268,7 +1268,7 @@
 
     std::vector<std::string> dList[20];
     int dListNum[20];
-    std::vector<std::string>* dListItem = 0;
+    std::vector<std::string>* dListItem = nullptr;
     std::string dListName[20];
     int ik, lk;
     std::string tk = "";
@@ -1422,7 +1422,7 @@
 
         p = p->nextIter();
 
-    } while ( p != 0 );
+    } while ( p != nullptr );
 
     return fs;
 }
@@ -1504,7 +1504,7 @@
             }
             p = p->nextIter( root_part );
 
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         //Now need to figure out which histogram to book
         trackAll->Fill( evTracks );
@@ -1643,7 +1643,7 @@
                                       5.9 * 5.9 ),
                                 0.0, 0.0, 5.9 );
 
-            EvtParticle* root_part = 0;
+            EvtParticle* root_part = nullptr;
             if ( neventOrig > 0 ) {
                 root_part = EvtParticleFactory::particleFactory( UPS4, p_init );
             } else {
@@ -1748,7 +1748,7 @@
             }
             EvtVector4R p_init( EvtPDL::getMass( UPS4 ), 0.0, 0.0, 0.0 );
 
-            EvtParticle* root_part = 0;
+            EvtParticle* root_part = nullptr;
             if ( neventOrig > 0 ) {
                 root_part = EvtParticleFactory::particleFactory( UPS4, p_init );
             } else {
@@ -3837,7 +3837,7 @@
 
         p_jpsi = root_part->getDaug( 0 );
 
-        p_rho = 0;
+        p_rho = nullptr;
 
         if ( p_jpsi->getDaug( 0 )->getNDaug() == 2 ) {
             p_rho = p_jpsi->getDaug( 0 );
@@ -3929,7 +3929,7 @@
             }
 
             if ( nDaug == 2 ) {
-                if ( p->getParent() == 0 ) {
+                if ( p->getParent() == nullptr ) {
                     EvtVector4R p4 = p->getDaug( 0 )->getP4();
                     double ctheta = p4.get( 3 ) / p4.d3mag();
                     double phi = atan2( p4.get( 2 ), p4.get( 1 ) );
@@ -4001,7 +4001,7 @@
 
             p = p->nextIter( root_part );
 
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         root_part->deleteTree();
 
@@ -4300,7 +4300,7 @@
             << "bId1a " << bId1a << " bId1b " << bId1b << " bId2a " << bId2a
             << " bId2b " << bId2b << " for event " << count << std::endl;
 
-        EvtParticle* Bpeng = 0;
+        EvtParticle* Bpeng = nullptr;
         //int bnum=0;
         int pengcount = 0;
         if ( ( ( bId1a == strangeid ) && ( bId1b == 22 ) ) ||
@@ -4515,7 +4515,7 @@
             << "bId1a " << bId1a << " bId1b " << bId1b << " bId2a " << bId2a
             << " bId2b " << bId2b << " for event " << count << std::endl;
 
-        EvtParticle* Bpeng = 0;
+        EvtParticle* Bpeng = nullptr;
         //int bnum=0;
         int pengcount = 0;
         if ( ( ( bId1a == strangeid ) && ( bId1b == 22 ) ) ||
@@ -4727,7 +4727,7 @@
 
         p = p->nextIter( root_part );
 
-    } while ( p != 0 );
+    } while ( p != nullptr );
 
     return temp;
 }
@@ -4745,7 +4745,7 @@
         //p->printTree();
         p = p->nextIter( root_part );
 
-    } while ( p != 0 );
+    } while ( p != nullptr );
     //EvtGenReport(EVTGEN_INFO,"EvtGen") << "done"<<std::endl;
     return temp;
 }
@@ -4771,7 +4771,7 @@
         }
 
         p = p->nextIter( root_part );
-    } while ( p != 0 );
+    } while ( p != nullptr );
 
     return temp;
 }
@@ -4983,7 +4983,7 @@
                    << std::endl;
             p = p->nextIter();
 
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         root_part->deleteTree();
 
@@ -5489,7 +5489,7 @@
 
             p = p->nextIter();
 
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         outmix << "event" << std::endl;
 
@@ -5538,7 +5538,7 @@
 
             p = p->nextIter();
 
-        } while ( p != 0 );
+        } while ( p != nullptr );
 
         //root_part->printTree();
 
diff --git a/test/example1.cc b/test/example1.cc
--- a/test/example1.cc
+++ b/test/example1.cc
@@ -46,10 +46,10 @@
 
 int main( int /*argc*/, char** /*argv*/ )
 {
-    EvtParticle* parent( 0 );
+    EvtParticle* parent( nullptr );
 
     // Define the random number generator
-    EvtRandomEngine* eng = 0;
+    EvtRandomEngine* eng = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -60,7 +60,7 @@
 
     EvtRandom::setRandomEngine( eng );
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
diff --git a/test/exampleWriteHepMC.cc b/test/exampleWriteHepMC.cc
--- a/test/exampleWriteHepMC.cc
+++ b/test/exampleWriteHepMC.cc
@@ -85,10 +85,10 @@
 
 int main( int /*argc*/, char** /*argv*/ )
 {
-    EvtParticle* parent( 0 );
+    EvtParticle* parent( nullptr );
 
     // Define the random number generator
-    EvtRandomEngine* eng = 0;
+    EvtRandomEngine* eng = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -99,7 +99,7 @@
 
     EvtRandom::setRandomEngine( eng );
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
diff --git a/validation/compareRootFiles.cc b/validation/compareRootFiles.cc
--- a/validation/compareRootFiles.cc
+++ b/validation/compareRootFiles.cc
@@ -435,13 +435,13 @@
 TH1D* compareRootFiles::getMtmHist( TFile* theFile, string histName,
                                     vector<int> groupInts )
 {
-    if ( theFile == 0 ) {
+    if ( theFile == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
 
     TTree* theTree = dynamic_cast<TTree*>( theFile->Get( "Data" ) );
-    if ( theTree == 0 ) {
+    if ( theTree == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
@@ -481,13 +481,13 @@
     // with bins along the x axis representing each group
     // leptons  gamma  pi+-  pi0   K+-  K0  D+-  D0  light_baryons  strange_baryons  other
 
-    if ( theFile == 0 ) {
+    if ( theFile == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
 
     TTree* theTree = dynamic_cast<TTree*>( theFile->Get( "Data" ) );
-    if ( theTree == 0 ) {
+    if ( theTree == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
@@ -563,13 +563,13 @@
 
 TH1D* compareRootFiles::getAllIdHist( TFile* theFile, string histName )
 {
-    if ( theFile == 0 ) {
+    if ( theFile == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
 
     TTree* theTree = dynamic_cast<TTree*>( theFile->Get( "Data" ) );
-    if ( theTree == 0 ) {
+    if ( theTree == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
@@ -598,13 +598,13 @@
 
 TH1D* compareRootFiles::getDaugHist( TFile* theFile, string histName )
 {
-    if ( theFile == 0 ) {
+    if ( theFile == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
 
     TTree* nDaugTree = dynamic_cast<TTree*>( theFile->Get( "nDaugTree" ) );
-    if ( nDaugTree == 0 ) {
+    if ( nDaugTree == nullptr ) {
         // Return empty histogram
         return _emptyHist;
     }
diff --git a/validation/genExampleRootFiles.cc b/validation/genExampleRootFiles.cc
--- a/validation/genExampleRootFiles.cc
+++ b/validation/genExampleRootFiles.cc
@@ -128,11 +128,11 @@
     dalitzTree->Branch( "invMass13Sq", &inv13Sq, "invMass13Sq/D" );
     dalitzTree->Branch( "invMass23Sq", &inv23Sq, "invMass23Sq/D" );
 
-    EvtParticle* baseParticle( 0 );
-    EvtParticle* theParent( 0 );
+    EvtParticle* baseParticle( nullptr );
+    EvtParticle* theParent( nullptr );
 
     // Define the random number generator
-    EvtRandomEngine* myRandomEngine = 0;
+    EvtRandomEngine* myRandomEngine = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -145,7 +145,7 @@
     // For our validation purposes, we just want to read in one decay file and create
     // plots from that.
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
@@ -206,7 +206,7 @@
 
         EvtId daugEvtId( -1, -1 );
         EvtParticle* baseDaughter = baseParticle->getDaug( 0 );
-        if ( baseDaughter != 0 ) {
+        if ( baseDaughter != nullptr ) {
             daugEvtId = baseDaughter->getId();
         }
 
@@ -227,7 +227,7 @@
         for ( iDaug = 0; iDaug < nDaug; iDaug++ ) {
             EvtParticle* daug = theParent->getDaug( iDaug );
 
-            if ( daug != 0 ) {
+            if ( daug != nullptr ) {
                 EvtVector4R p4Lab = daug->getP4Lab();
                 EvtVector4R pos4 = daug->get4Pos();
 
diff --git a/validation/genRootDecayChain.cc b/validation/genRootDecayChain.cc
--- a/validation/genRootDecayChain.cc
+++ b/validation/genRootDecayChain.cc
@@ -101,10 +101,10 @@
     _parentName( parentName ),
     _nEvents( nEvents ),
     _storeMtmXYZ( storeMtmXYZ ),
-    _theFile( 0 ),
-    _theTree( 0 ),
-    _probHist( 0 ),
-    _theCanvas( 0 )
+    _theFile( nullptr ),
+    _theTree( nullptr ),
+    _probHist( nullptr ),
+    _theCanvas( nullptr )
 {
     _theFile = new TFile( rootFileName.c_str(), "recreate" );
     _theTree = new TTree( "Data", "Data" );
@@ -178,8 +178,8 @@
 
 void genRootDecayChain::generateEvents()
 {
-    EvtRandomEngine* randomEngine = 0;
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtRandomEngine* randomEngine = nullptr;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
     // Define the random number generator
@@ -207,7 +207,7 @@
     EvtGen evtGen( _decayFileName.c_str(), "../evt.pdl", randomEngine,
                    radCorrEngine, &extraModels, mixingType, useXml );
 
-    EvtParticle* theParent( 0 );
+    EvtParticle* theParent( nullptr );
 
     EvtId theId = EvtPDL::getId( _parentName );
     if ( theId.getId() == -1 && theId.getAlias() == -1 ) {
diff --git a/validation/testCPVDecays.cc b/validation/testCPVDecays.cc
--- a/validation/testCPVDecays.cc
+++ b/validation/testCPVDecays.cc
@@ -111,7 +111,7 @@
 
     // Define the random number generator
 
-    EvtRandomEngine* myRandomEngine = 0;
+    EvtRandomEngine* myRandomEngine = nullptr;
 
 #ifdef EVTGEN_CPP11
     // Use the Mersenne-Twister generator (C++11 only)
@@ -120,7 +120,7 @@
     myRandomEngine = new EvtSimpleRandomEngine();
 #endif
 
-    EvtAbsRadCorr* radCorrEngine = 0;
+    EvtAbsRadCorr* radCorrEngine = nullptr;
     std::list<EvtDecayBase*> extraModels;
 
 #ifdef EVTGEN_EXTERNAL
@@ -147,7 +147,7 @@
 
     // Start all initial (parent) decays at the origin
     EvtVector4R origin( 0.0, 0.0, 0.0, 0.0 );
-    EvtSpinDensity* spinDensity = 0;
+    EvtSpinDensity* spinDensity = nullptr;
 
     EvtSpinType::spintype baseSpin = EvtPDL::getSpinType( theId );
 
@@ -259,7 +259,7 @@
 
     // Loop over vertices in the event
     for ( auto theVertex : theEvent->vertices() ) {
-        if ( theVertex == 0 ) {
+        if ( theVertex == nullptr ) {
             continue;
         }
 
@@ -272,7 +272,7 @@
         FourVector B4mtm;
 
         for ( auto inParticle : theVertex->particles_in() ) {
-            if ( inParticle == 0 ) {
+            if ( inParticle == nullptr ) {
                 continue;
             }
 
@@ -293,7 +293,7 @@
             // Check outgoing particles
             std::vector<int> daugIdVect;
             for ( auto outParticle : theVertex->particles_out() ) {
-                if ( outParticle != 0 ) {
+                if ( outParticle != nullptr ) {
                     int outPDGId = outParticle->pdg_id();
                     daugIdVect.push_back( outPDGId );
                 }
@@ -337,7 +337,7 @@
         // Get the vertex
         HepMC::GenVertex* theVertex = *vertexIter;
 
-        if ( theVertex == 0 ) {
+        if ( theVertex == nullptr ) {
             continue;
         }
 
@@ -354,7 +354,7 @@
               inIter != theVertex->particles_in_const_end(); ++inIter ) {
             HepMC::GenParticle* inParticle = *inIter;
 
-            if ( inParticle == 0 ) {
+            if ( inParticle == nullptr ) {
                 continue;
             }
 
@@ -379,7 +379,7 @@
                   outIter != theVertex->particles_out_const_end(); ++outIter ) {
                 HepMC::GenParticle* outParticle = *outIter;
 
-                if ( outParticle != 0 ) {
+                if ( outParticle != nullptr ) {
                     int outPDGId = outParticle->pdg_id();
                     daugIdVect.push_back( outPDGId );
                 }