diff --git a/dynare++/integ/cc/product.cc b/dynare++/integ/cc/product.cc
index d796a374d..c79422419 100644
--- a/dynare++/integ/cc/product.cc
+++ b/dynare++/integ/cc/product.cc
@@ -4,8 +4,8 @@
 #include "symmetry.hh"
 
 prodpit::prodpit()
-  : prodq(NULL),  jseq(NULL),
-     sig(NULL), p(NULL)
+  : prodq(nullptr),  jseq(nullptr),
+     sig(nullptr), p(nullptr)
 {
 }
 
@@ -33,15 +33,15 @@ prodpit::prodpit(const prodpit &ppit)
   if (ppit.jseq)
     jseq = new IntSequence(*(ppit.jseq));
   else
-    jseq = NULL;
+    jseq = nullptr;
   if (ppit.sig)
     sig = new ParameterSignal(*(ppit.sig));
   else
-    sig = NULL;
+    sig = nullptr;
   if (ppit.p)
     p = new Vector(*(ppit.p));
   else
-    p = NULL;
+    p = nullptr;
 }
 
 prodpit::~prodpit()
@@ -60,8 +60,8 @@ prodpit::operator==(const prodpit &ppit) const
   bool ret = true;
   ret = ret & prodq == ppit.prodq;
   ret = ret & end_flag == ppit.end_flag;
-  ret = ret & ((jseq == NULL && ppit.jseq == NULL)
-               || (jseq != NULL && ppit.jseq != NULL && *jseq == *(ppit.jseq)));
+  ret = ret & ((jseq == nullptr && ppit.jseq == nullptr)
+               || (jseq != nullptr && ppit.jseq != nullptr && *jseq == *(ppit.jseq)));
   return ret;
 }
 
@@ -82,15 +82,15 @@ prodpit::operator=(const prodpit &ppit)
   if (ppit.jseq)
     jseq = new IntSequence(*(ppit.jseq));
   else
-    jseq = NULL;
+    jseq = nullptr;
   if (ppit.sig)
     sig = new ParameterSignal(*(ppit.sig));
   else
-    sig = NULL;
+    sig = nullptr;
   if (ppit.p)
     p = new Vector(*(ppit.p));
   else
-    p = NULL;
+    p = nullptr;
 
   return *this;
 }
diff --git a/dynare++/integ/cc/quadrature.hh b/dynare++/integ/cc/quadrature.hh
index d68272c7b..02cf1bc4e 100644
--- a/dynare++/integ/cc/quadrature.hh
+++ b/dynare++/integ/cc/quadrature.hh
@@ -188,7 +188,7 @@ public:
   savePoints(const char *fname, int level) const
   {
     FILE *fd;
-    if (NULL == (fd = fopen(fname, "w")))
+    if (nullptr == (fd = fopen(fname, "w")))
       {
         // todo: raise
         fprintf(stderr, "Cannot open file %s for writing.\n", fname);
diff --git a/dynare++/integ/cc/quasi_mcarlo.cc b/dynare++/integ/cc/quasi_mcarlo.cc
index 8df7be8f8..9c7f9a6f1 100644
--- a/dynare++/integ/cc/quasi_mcarlo.cc
+++ b/dynare++/integ/cc/quasi_mcarlo.cc
@@ -162,7 +162,7 @@ HaltonSequence::print() const
 }
 
 qmcpit::qmcpit()
-  : spec(NULL), halton(NULL), sig(NULL)
+  : spec(nullptr), halton(nullptr), sig(nullptr)
 {
 }
 
@@ -173,7 +173,7 @@ qmcpit::qmcpit(const QMCSpecification &s, int n)
 }
 
 qmcpit::qmcpit(const qmcpit &qpit)
-  : spec(qpit.spec), halton(NULL), sig(NULL)
+  : spec(qpit.spec), halton(nullptr), sig(nullptr)
 {
   if (qpit.halton)
     halton = new HaltonSequence(*(qpit.halton));
@@ -193,8 +193,8 @@ bool
 qmcpit::operator==(const qmcpit &qpit) const
 {
   return (spec == qpit.spec)
-    && ((halton == NULL && qpit.halton == NULL)
-        || (halton != NULL && qpit.halton != NULL && halton->getNum() == qpit.halton->getNum()));
+    && ((halton == nullptr && qpit.halton == nullptr)
+        || (halton != nullptr && qpit.halton != nullptr && halton->getNum() == qpit.halton->getNum()));
 }
 
 const qmcpit &
@@ -206,7 +206,7 @@ qmcpit::operator=(const qmcpit &qpit)
   if (qpit.halton)
     halton = new HaltonSequence(*(qpit.halton));
   else
-    halton = NULL;
+    halton = nullptr;
   return *this;
 }
 
@@ -225,7 +225,7 @@ qmcpit::weight() const
 }
 
 qmcnpit::qmcnpit()
-  : qmcpit(), pnt(NULL)
+  : qmcpit(), pnt(nullptr)
 {
 }
 
@@ -235,7 +235,7 @@ qmcnpit::qmcnpit(const QMCSpecification &s, int n)
 }
 
 qmcnpit::qmcnpit(const qmcnpit &qpit)
-  : qmcpit(qpit), pnt(NULL)
+  : qmcpit(qpit), pnt(nullptr)
 {
   if (qpit.pnt)
     pnt = new Vector(*(qpit.pnt));
@@ -256,7 +256,7 @@ qmcnpit::operator=(const qmcnpit &qpit)
   if (qpit.pnt)
     pnt = new Vector(*(qpit.pnt));
   else
-    pnt = NULL;
+    pnt = nullptr;
   return *this;
 }
 
diff --git a/dynare++/integ/cc/smolyak.cc b/dynare++/integ/cc/smolyak.cc
index 0475cea80..b2495fefa 100644
--- a/dynare++/integ/cc/smolyak.cc
+++ b/dynare++/integ/cc/smolyak.cc
@@ -4,7 +4,7 @@
 #include "symmetry.hh"
 
 smolpit::smolpit()
-  : smolq(NULL),  jseq(NULL), sig(NULL), p(NULL)
+  : smolq(nullptr),  jseq(nullptr), sig(nullptr), p(nullptr)
 {
 }
 
@@ -28,15 +28,15 @@ smolpit::smolpit(const smolpit &spit)
   if (spit.jseq)
     jseq = new IntSequence(*(spit.jseq));
   else
-    jseq = NULL;
+    jseq = nullptr;
   if (spit.sig)
     sig = new ParameterSignal(*(spit.sig));
   else
-    sig = NULL;
+    sig = nullptr;
   if (spit.p)
     p = new Vector(*(spit.p));
   else
-    p = NULL;
+    p = nullptr;
 }
 
 smolpit::~smolpit()
@@ -55,8 +55,8 @@ smolpit::operator==(const smolpit &spit) const
   bool ret = true;
   ret = ret & smolq == spit.smolq;
   ret = ret & isummand == spit.isummand;
-  ret = ret & ((jseq == NULL && spit.jseq == NULL)
-               || (jseq != NULL && spit.jseq != NULL && *jseq == *(spit.jseq)));
+  ret = ret & ((jseq == nullptr && spit.jseq == nullptr)
+               || (jseq != nullptr && spit.jseq != nullptr && *jseq == *(spit.jseq)));
   return ret;
 }
 
@@ -77,15 +77,15 @@ smolpit::operator=(const smolpit &spit)
   if (spit.jseq)
     jseq = new IntSequence(*(spit.jseq));
   else
-    jseq = NULL;
+    jseq = nullptr;
   if (spit.sig)
     sig = new ParameterSignal(*(spit.sig));
   else
-    sig = NULL;
+    sig = nullptr;
   if (spit.p)
     p = new Vector(*(spit.p));
   else
-    p = NULL;
+    p = nullptr;
 
   return *this;
 }
diff --git a/dynare++/integ/src/quadrature-points.cc b/dynare++/integ/src/quadrature-points.cc
index 2e2c6e08f..dcdb9f687 100644
--- a/dynare++/integ/src/quadrature-points.cc
+++ b/dynare++/integ/src/quadrature-points.cc
@@ -29,7 +29,7 @@ private:
 };
 
 QuadParams::QuadParams(int argc, char **argv)
-  : outname(NULL), vcovname(NULL), max_level(3), discard_weight(0.0)
+  : outname(nullptr), vcovname(nullptr), max_level(3), discard_weight(0.0)
 {
   if (argc == 1)
     {
@@ -41,10 +41,10 @@ QuadParams::QuadParams(int argc, char **argv)
   argc--;
 
   struct option const opts [] = {
-    {"max-level", required_argument, NULL, opt_max_level},
-    {"discard-weight", required_argument, NULL, opt_discard_weight},
-    {"vcov", required_argument, NULL, opt_vcov},
-    {NULL, 0, NULL, 0}
+    {"max-level", required_argument, nullptr, opt_max_level},
+    {"discard-weight", required_argument, nullptr, opt_discard_weight},
+    {"vcov", required_argument, nullptr, opt_vcov},
+    {nullptr, 0, nullptr, 0}
   };
 
   int ret;
@@ -73,13 +73,13 @@ QuadParams::QuadParams(int argc, char **argv)
 void
 QuadParams::check_consistency() const
 {
-  if (outname == NULL)
+  if (outname == nullptr)
     {
       fprintf(stderr, "Error: output name not set\n");
       exit(1);
     }
 
-  if (vcovname == NULL)
+  if (vcovname == nullptr)
     {
       fprintf(stderr, "Error: vcov file name not set\n");
       exit(1);
@@ -104,7 +104,7 @@ main(int argc, char **argv)
 
   // open output file for writing
   FILE *fout;
-  if (NULL == (fout = fopen(params.outname, "w")))
+  if (nullptr == (fout = fopen(params.outname, "w")))
     {
       fprintf(stderr, "Could not open %s for writing\n", params.outname);
       exit(1);
diff --git a/dynare++/integ/testing/tests.cc b/dynare++/integ/testing/tests.cc
index 97a0250a3..85e087633 100644
--- a/dynare++/integ/testing/tests.cc
+++ b/dynare++/integ/testing/tests.cc
@@ -172,12 +172,12 @@ class WallTimer
 public:
   WallTimer(const char *m, bool nl = true)
   {
-    strcpy(mes, m); new_line = nl; gettimeofday(&start, NULL);
+    strcpy(mes, m); new_line = nl; gettimeofday(&start, nullptr);
   }
   ~WallTimer()
   {
     struct timeval end;
-    gettimeofday(&end, NULL);
+    gettimeofday(&end, nullptr);
     printf("%s%8.4g", mes,
            end.tv_sec-start.tv_sec + (end.tv_usec-start.tv_usec)*1.0e-6);
     if (new_line)
diff --git a/dynare++/kord/approximation.cc b/dynare++/kord/approximation.cc
index eb0a3fdf4..41085d8e6 100644
--- a/dynare++/kord/approximation.cc
+++ b/dynare++/kord/approximation.cc
@@ -30,7 +30,7 @@ ZAuxContainer::getType(int i, const Symmetry &s) const
 }
 
 Approximation::Approximation(DynamicModel &m, Journal &j, int ns, bool dr_centr, double qz_crit)
-  : model(m), journal(j), rule_ders(NULL), rule_ders_ss(NULL), fdr(NULL), udr(NULL),
+  : model(m), journal(j), rule_ders(nullptr), rule_ders_ss(nullptr), fdr(nullptr), udr(nullptr),
     ypart(model.nstat(), model.npred(), model.nboth(), model.nforw()),
     mom(UNormalMoments(model.order(), model.getVcov())), nvs(4), steps(ns),
     dr_centralize(dr_centr), qz_criterium(qz_crit), ss(ypart.ny(), steps+1)
@@ -57,7 +57,7 @@ Approximation::~Approximation()
 const FoldDecisionRule &
 Approximation::getFoldDecisionRule() const
 {
-  KORD_RAISE_IF(fdr == NULL,
+  KORD_RAISE_IF(fdr == nullptr,
                 "Folded decision rule has not been created in Approximation::getFoldDecisionRule");
   return *fdr;
 }
@@ -66,7 +66,7 @@ Approximation::getFoldDecisionRule() const
 const UnfoldDecisionRule &
 Approximation::getUnfoldDecisionRule() const
 {
-  KORD_RAISE_IF(udr == NULL,
+  KORD_RAISE_IF(udr == nullptr,
                 "Unfolded decision rule has not been created in Approximation::getUnfoldDecisionRule");
   return *udr;
 }
@@ -208,12 +208,12 @@ Approximation::walkStochSteady()
   if (fdr)
     {
       delete fdr;
-      fdr = NULL;
+      fdr = nullptr;
     }
   if (udr)
     {
       delete udr;
-      udr = NULL;
+      udr = nullptr;
     }
 
   fdr = new FoldDecisionRule(*rule_ders, ypart, model.nexog(),
diff --git a/dynare++/kord/decision_rule.cc b/dynare++/kord/decision_rule.cc
index b86b0ef76..c3fd545f6 100644
--- a/dynare++/kord/decision_rule.cc
+++ b/dynare++/kord/decision_rule.cc
@@ -132,8 +132,8 @@ SimResults::writeMat(const char *base, const char *lname) const
 {
   char matfile_name[100];
   sprintf(matfile_name, "%s.mat", base);
-  mat_t *matfd = Mat_Create(matfile_name, NULL);
-  if (matfd != NULL)
+  mat_t *matfd = Mat_Create(matfile_name, nullptr);
+  if (matfd != nullptr)
     {
       writeMat(matfd, lname);
       Mat_Close(matfd);
diff --git a/dynare++/kord/decision_rule.hh b/dynare++/kord/decision_rule.hh
index b15aeebf6..bc4f996af 100644
--- a/dynare++/kord/decision_rule.hh
+++ b/dynare++/kord/decision_rule.hh
@@ -534,7 +534,7 @@ template <int t>
 DRFixPoint<t>::DRFixPoint(const _Tg &g, const PartitionY &yp,
                           const Vector &ys, double sigma)
   : ctraits<t>::Tpol(yp.ny(), yp.nys()),
-  ysteady(ys), ypart(yp), bigf(NULL), bigfder(NULL)
+  ysteady(ys), ypart(yp), bigf(nullptr), bigfder(nullptr)
 {
   fillTensors(g, sigma);
   _Tparent yspol(ypart.nstat, ypart.nys(), *this);
diff --git a/dynare++/kord/global_check.cc b/dynare++/kord/global_check.cc
index 415765f12..6cfb304ba 100644
--- a/dynare++/kord/global_check.cc
+++ b/dynare++/kord/global_check.cc
@@ -16,13 +16,13 @@
 ResidFunction::ResidFunction(const Approximation &app)
   : VectorFunction(app.getModel().nexog(), app.getModel().numeq()), approx(app),
     model(app.getModel().clone()),
-    yplus(NULL), ystar(NULL), u(NULL), hss(NULL)
+    yplus(nullptr), ystar(nullptr), u(nullptr), hss(nullptr)
 {
 }
 
 ResidFunction::ResidFunction(const ResidFunction &rf)
   : VectorFunction(rf), approx(rf.approx), model(rf.model->clone()),
-    yplus(NULL), ystar(NULL), u(NULL), hss(NULL)
+    yplus(nullptr), ystar(nullptr), u(nullptr), hss(nullptr)
 {
   if (rf.yplus)
     yplus = new Vector(*(rf.yplus));
diff --git a/dynare++/kord/journal.cc b/dynare++/kord/journal.cc
index 395693afb..1c5fc5e08 100644
--- a/dynare++/kord/journal.cc
+++ b/dynare++/kord/journal.cc
@@ -67,7 +67,7 @@ sysconf(int name)
 
 SystemResources::SystemResources()
 {
-  gettimeofday(&start, NULL);
+  gettimeofday(&start, nullptr);
 }
 
 long int
@@ -103,7 +103,7 @@ SystemResources::getRUS(double &load_avg, long int &pg_avail,
                         long int &idrss, long int &majflt)
 {
   struct timeval now;
-  gettimeofday(&now, NULL);
+  gettimeofday(&now, nullptr);
   elapsed = now.tv_sec-start.tv_sec + (now.tv_usec-start.tv_usec)*1.0e-6;
 
 #if !defined(__MINGW32__)
@@ -239,7 +239,7 @@ Journal::printHeader()
 
   (*this)<< "\n\nStart time: ";
   char ts[100];
-  time_t curtime = time(NULL);
+  time_t curtime = time(nullptr);
   tm loctime;
   localtime_r(&curtime, &loctime);
   asctime_r(&loctime, ts);
diff --git a/dynare++/kord/korder_stoch.cc b/dynare++/kord/korder_stoch.cc
index 768e25f8d..ae0880c76 100644
--- a/dynare++/kord/korder_stoch.cc
+++ b/dynare++/kord/korder_stoch.cc
@@ -29,7 +29,7 @@ KOrderStoch::KOrderStoch(const PartitionY &yp, int nu,
                          const FGSContainer &hh, Journal &jr)
   : nvs(4), ypart(yp), journal(jr),
     _ug(4), _fg(4), _ugs(4), _fgs(4), _uG(4), _fG(4),
-    _uh(NULL), _fh(&hh),
+    _uh(nullptr), _fh(&hh),
     _uZstack(&_uG, ypart.nyss(), &_ug, ypart.ny(), ypart.nys(), nu),
     _fZstack(&_fG, ypart.nyss(), &_fg, ypart.ny(), ypart.nys(), nu),
     _uGstack(&_ugs, ypart.nys(), nu),
@@ -50,7 +50,7 @@ KOrderStoch::KOrderStoch(const PartitionY &yp, int nu,
                          const UGSContainer &hh, Journal &jr)
   : nvs(4), ypart(yp), journal(jr),
     _ug(4), _fg(4), _ugs(4), _fgs(4), _uG(4), _fG(4),
-    _uh(&hh), _fh(NULL),
+    _uh(&hh), _fh(nullptr),
     _uZstack(&_uG, ypart.nyss(), &_ug, ypart.ny(), ypart.nys(), nu),
     _fZstack(&_fG, ypart.nyss(), &_fg, ypart.ny(), ypart.nys(), nu),
     _uGstack(&_ugs, ypart.nys(), nu),
diff --git a/dynare++/parser/cc/atom_substitutions.cc b/dynare++/parser/cc/atom_substitutions.cc
index 64436bf2c..c48c059d9 100644
--- a/dynare++/parser/cc/atom_substitutions.cc
+++ b/dynare++/parser/cc/atom_substitutions.cc
@@ -35,7 +35,7 @@ AtomSubstitutions::add_substitution(const char *newname, const char *oldname, in
   // make sure the storage is from the new_atoms
   newname = new_atoms.get_name_storage().query(newname);
   oldname = new_atoms.get_name_storage().query(oldname);
-  if (newname == NULL || oldname == NULL)
+  if (newname == nullptr || oldname == nullptr)
     throw ogu::Exception(__FILE__, __LINE__,
                          "Bad newname or oldname in AtomSubstitutions::add_substitution");
 
@@ -88,7 +88,7 @@ AtomSubstitutions::get_new4old(const char *oldname, int tshift) const
         if (itt.second == -tshift)
           return itt.first;
     }
-  return NULL;
+  return nullptr;
 }
 
 void
@@ -114,19 +114,19 @@ SAtoms::substituteAllLagsAndLeads(FormulaParser &fp, AtomSubstitutions &as)
   endovarspan(mlead, mlag);
 
   // substitute all endo lagged more than 1
-  while (NULL != (name = findEndoWithLeadInInterval(mlag, -2)))
+  while (nullptr != (name = findEndoWithLeadInInterval(mlag, -2)))
     makeAuxVariables(name, -1, -2, mlag, fp, as);
   // substitute all endo leaded more than 1
-  while (NULL != (name = findEndoWithLeadInInterval(2, mlead)))
+  while (nullptr != (name = findEndoWithLeadInInterval(2, mlead)))
     makeAuxVariables(name, 1, 2, mlead, fp, as);
 
   exovarspan(mlead, mlag);
 
   // substitute all lagged exo
-  while (NULL != (name = findExoWithLeadInInterval(mlag, -1)))
+  while (nullptr != (name = findExoWithLeadInInterval(mlag, -1)))
     makeAuxVariables(name, -1, -1, mlag, fp, as);
   // substitute all leaded exo
-  while (NULL != (name = findExoWithLeadInInterval(1, mlead)))
+  while (nullptr != (name = findExoWithLeadInInterval(1, mlead)))
     makeAuxVariables(name, 1, 1, mlead, fp, as);
 
   // notify that substitution have been finished
@@ -142,16 +142,16 @@ SAtoms::substituteAllLagsAndExo1Leads(FormulaParser &fp, AtomSubstitutions &as)
   endovarspan(mlead, mlag);
 
   // substitute all endo lagged more than 1
-  while (NULL != (name = findEndoWithLeadInInterval(mlag, -2)))
+  while (nullptr != (name = findEndoWithLeadInInterval(mlag, -2)))
     makeAuxVariables(name, -1, -2, mlag, fp, as);
 
   exovarspan(mlead, mlag);
 
   // substitute all lagged exo
-  while (NULL != (name = findExoWithLeadInInterval(mlag, -1)))
+  while (nullptr != (name = findExoWithLeadInInterval(mlag, -1)))
     makeAuxVariables(name, -1, -1, mlag, fp, as);
   // substitute all leaded exo by 1
-  while (NULL != (name = findExoWithLeadInInterval(1, 1)))
+  while (nullptr != (name = findExoWithLeadInInterval(1, 1)))
     makeAuxVariables(name, 1, 1, 1, fp, as);
 
   // notify that substitution have been finished
@@ -175,7 +175,7 @@ SAtoms::findNameWithLeadInInterval(const vector<const char *> &names,
     }
 
   // nothing found
-  return NULL;
+  return nullptr;
 }
 
 void
@@ -242,7 +242,7 @@ SAtoms::makeAuxVariables(const char *name, int step, int start, int limit_lead,
       const char *newname;
       string newname_str;
       int taux;
-      if (NULL == (newname = as.get_new4old(name, ll-step)))
+      if (nullptr == (newname = as.get_new4old(name, ll-step)))
         {
           attemptAuxName(name, ll-step, newname_str);
           newname = newname_str.c_str();
diff --git a/dynare++/parser/cc/csv_parser.cc b/dynare++/parser/cc/csv_parser.cc
index 1f0a8737f..5b53f47a2 100644
--- a/dynare++/parser/cc/csv_parser.cc
+++ b/dynare++/parser/cc/csv_parser.cc
@@ -40,5 +40,5 @@ CSVParser::csv_parse(int length, const char *str)
   ::csv_parse();
   delete [] buffer;
   csv__destroy_buffer(p);
-  parsed_string = NULL;
+  parsed_string = nullptr;
 }
diff --git a/dynare++/parser/cc/csv_parser.hh b/dynare++/parser/cc/csv_parser.hh
index f5970f205..31d8402ea 100644
--- a/dynare++/parser/cc/csv_parser.hh
+++ b/dynare++/parser/cc/csv_parser.hh
@@ -25,7 +25,7 @@ namespace ogp
     const char *parsed_string;
   public:
     CSVParser(CSVParserPeer &p)
-      : peer(p), row(0), col(0), parsed_string(0)
+      : peer(p), row(0), col(0), parsed_string(nullptr)
     {
     }
     CSVParser(const CSVParser &csvp)
diff --git a/dynare++/parser/cc/dynamic_atoms.cc b/dynare++/parser/cc/dynamic_atoms.cc
index b7519d87d..5c11676bd 100644
--- a/dynare++/parser/cc/dynamic_atoms.cc
+++ b/dynare++/parser/cc/dynamic_atoms.cc
@@ -32,7 +32,7 @@ NameStorage::query(const char *name) const
 {
   auto it = name_set.find(name);
   if (it == name_set.end())
-    return NULL;
+    return nullptr;
   else
     return (*it);
 }
diff --git a/dynare++/parser/cc/fine_atoms.cc b/dynare++/parser/cc/fine_atoms.cc
index e77160557..0c7ef1cb9 100644
--- a/dynare++/parser/cc/fine_atoms.cc
+++ b/dynare++/parser/cc/fine_atoms.cc
@@ -76,7 +76,7 @@ AllvarOuterOrdering::AllvarOuterOrdering(const AllvarOuterOrdering &avo,
 
 FineAtoms::FineAtoms(const FineAtoms &fa)
   : DynamicAtoms(fa), params(), endovars(), exovars(),
-    endo_order(NULL), exo_order(NULL), allvar_order(NULL),
+    endo_order(nullptr), exo_order(nullptr), allvar_order(nullptr),
     der_atoms(fa.der_atoms),
     endo_atoms_map(fa.endo_atoms_map),
     exo_atoms_map(fa.exo_atoms_map)
diff --git a/dynare++/parser/cc/fine_atoms.hh b/dynare++/parser/cc/fine_atoms.hh
index 610b6b7c4..e24e584bb 100644
--- a/dynare++/parser/cc/fine_atoms.hh
+++ b/dynare++/parser/cc/fine_atoms.hh
@@ -229,7 +229,7 @@ namespace ogp
     vector<int> exo_atoms_map;
   public:
     FineAtoms()
-      : endo_order(NULL), exo_order(NULL), allvar_order(NULL)
+      : endo_order(nullptr), exo_order(nullptr), allvar_order(nullptr)
     {
     }
     FineAtoms(const FineAtoms &fa);
diff --git a/dynare++/parser/cc/matrix_parser.hh b/dynare++/parser/cc/matrix_parser.hh
index 88d41b655..19e9b1456 100644
--- a/dynare++/parser/cc/matrix_parser.hh
+++ b/dynare++/parser/cc/matrix_parser.hh
@@ -91,7 +91,7 @@ namespace ogp
     int r{0};
 
   public:
-    MPIterator() : p(NULL) 
+    MPIterator() : p(nullptr) 
     {
     }
     /** Constructs an iterator pointing to the beginning of the
diff --git a/dynare++/parser/cc/parser_exception.cc b/dynare++/parser/cc/parser_exception.cc
index e9512b582..fc4e2519e 100644
--- a/dynare++/parser/cc/parser_exception.cc
+++ b/dynare++/parser/cc/parser_exception.cc
@@ -48,7 +48,7 @@ ParserException::ParserException(const string &m, const char *dum, int i1, int i
 }
 
 ParserException::ParserException(const ParserException &m, int plus_offset)
-  : mes(NULL),
+  : mes(nullptr),
     aux_i1(-1), aux_i2(-1), aux_i3(-1)
 {
   copy(m);
@@ -56,7 +56,7 @@ ParserException::ParserException(const ParserException &m, int plus_offset)
 }
 
 ParserException::ParserException(const ParserException &m, const char *dum, int i)
-  : mes(NULL),
+  : mes(nullptr),
     aux_i1(-1), aux_i2(-1), aux_i3(-1)
 {
   copy(m);
@@ -66,7 +66,7 @@ ParserException::ParserException(const ParserException &m, const char *dum, int
 }
 
 ParserException::ParserException(const ParserException &m, const char *dum, int i1, int i2)
-  : mes(NULL),
+  : mes(nullptr),
     aux_i1(-1), aux_i2(-1), aux_i3(-1)
 {
   copy(m);
@@ -76,7 +76,7 @@ ParserException::ParserException(const ParserException &m, const char *dum, int
 }
 
 ParserException::ParserException(const ParserException &m, const char *dum, int i1, int i2, int i3)
-  : mes(NULL),
+  : mes(nullptr),
     aux_i1(-1), aux_i2(-1), aux_i3(-1)
 {
   copy(m);
@@ -86,7 +86,7 @@ ParserException::ParserException(const ParserException &m, const char *dum, int
 }
 
 ParserException::ParserException(const ParserException &e)
-  : mes(NULL),
+  : mes(nullptr),
     aux_i1(-1), aux_i2(-1), aux_i3(-1)
 {
   copy(e);
diff --git a/dynare++/parser/cc/static_atoms.cc b/dynare++/parser/cc/static_atoms.cc
index f742e6af2..5fc58169c 100644
--- a/dynare++/parser/cc/static_atoms.cc
+++ b/dynare++/parser/cc/static_atoms.cc
@@ -84,7 +84,7 @@ StaticAtoms::inv_index(int t) const
 {
   auto it = indices.find(t);
   if (it == indices.end())
-    return NULL;
+    return nullptr;
   else
     return (*it).second;
 }
diff --git a/dynare++/parser/cc/static_fine_atoms.cc b/dynare++/parser/cc/static_fine_atoms.cc
index e2c8ee938..54f06f7df 100644
--- a/dynare++/parser/cc/static_fine_atoms.cc
+++ b/dynare++/parser/cc/static_fine_atoms.cc
@@ -97,7 +97,7 @@ int
 StaticFineAtoms::check_variable(const char *name) const
 {
   const char *ss = varnames.query(name);
-  if (ss == NULL)
+  if (ss == nullptr)
     throw ParserException(string("Variable <")+name+"> not declared.", 0);
   return index(name);
 }
@@ -208,7 +208,7 @@ void
 StaticFineAtoms::register_endo(const char *name)
 {
   const char *ss = varnames.query(name);
-  if (ss == NULL)
+  if (ss == nullptr)
     throw ogp::ParserException(string("Endogenous variable <")
                                +name+"> not found in storage.", 0);
   endovars.push_back(ss);
@@ -219,7 +219,7 @@ void
 StaticFineAtoms::register_exo(const char *name)
 {
   const char *ss = varnames.query(name);
-  if (ss == NULL)
+  if (ss == nullptr)
     throw ogp::ParserException(string("Exogenous variable <")
                                +name+"> not found in storage.", 0);
   exovars.push_back(ss);
@@ -230,7 +230,7 @@ void
 StaticFineAtoms::register_param(const char *name)
 {
   const char *ss = varnames.query(name);
-  if (ss == NULL)
+  if (ss == nullptr)
     throw ogp::ParserException(string("Parameter <")+name+"> not found in storage.", 0);
   params.push_back(ss);
   param_outer_map.insert(Tvarintmap::value_type(ss, params.size()-1));
diff --git a/dynare++/src/dynare3.cc b/dynare++/src/dynare3.cc
index b0239709e..7dfc2d239 100644
--- a/dynare++/src/dynare3.cc
+++ b/dynare++/src/dynare3.cc
@@ -40,8 +40,8 @@ DynareNameList::selectIndices(const vector<const char *> &ns) const
 /**************************************************************************************/
 
 Dynare::Dynare(const char *modname, int ord, double sstol, Journal &jr)
-  : journal(jr), model(NULL), ysteady(NULL), md(1), dnl(NULL), denl(NULL), dsnl(NULL),
-    fe(NULL), fde(NULL), ss_tol(sstol)
+  : journal(jr), model(nullptr), ysteady(nullptr), md(1), dnl(nullptr), denl(nullptr), dsnl(nullptr),
+    fe(nullptr), fde(nullptr), ss_tol(sstol)
 {
   // make memory file
   ogu::MemoryFile mf(modname);
@@ -77,8 +77,8 @@ Dynare::Dynare(const char **endo, int num_endo,
                const char **par, int num_par,
                const char *equations, int len, int ord,
                double sstol, Journal &jr)
-  : journal(jr), model(NULL), ysteady(NULL), md(1), dnl(NULL), denl(NULL), dsnl(NULL),
-    fe(NULL), fde(NULL), ss_tol(sstol)
+  : journal(jr), model(nullptr), ysteady(nullptr), md(1), dnl(nullptr), denl(nullptr), dsnl(nullptr),
+    fe(nullptr), fde(nullptr), ss_tol(sstol)
 {
   try
     {
@@ -99,9 +99,9 @@ Dynare::Dynare(const char **endo, int num_endo,
 }
 
 Dynare::Dynare(const Dynare &dynare)
-  : journal(dynare.journal), model(NULL),
-    ysteady(NULL), md(dynare.md),
-    dnl(NULL), denl(NULL), dsnl(NULL), fe(NULL), fde(NULL),
+  : journal(dynare.journal), model(nullptr),
+    ysteady(nullptr), md(dynare.md),
+    dnl(nullptr), denl(nullptr), dsnl(nullptr), fe(nullptr), fde(nullptr),
     ss_tol(dynare.ss_tol)
 {
   model = dynare.model->clone();
diff --git a/dynare++/src/dynare_atoms.cc b/dynare++/src/dynare_atoms.cc
index a7e8f9d61..34d3ba355 100644
--- a/dynare++/src/dynare_atoms.cc
+++ b/dynare++/src/dynare_atoms.cc
@@ -24,7 +24,7 @@ DynareStaticAtoms::register_name(const char *name)
 int
 DynareStaticAtoms::check_variable(const char *name) const
 {
-  if (0 == varnames.query(name))
+  if (nullptr == varnames.query(name))
     throw ogp::ParserException(std::string("Unknown name <")+name+">", 0);
   auto it = vars.find(name);
   if (it == vars.end())
diff --git a/dynare++/src/dynare_model.cc b/dynare++/src/dynare_model.cc
index 84fa6c2a1..ae660fbcc 100644
--- a/dynare++/src/dynare_model.cc
+++ b/dynare++/src/dynare_model.cc
@@ -27,18 +27,18 @@ ParsedMatrix::ParsedMatrix(const ogp::MatrixParser &mp)
 
 DynareModel::DynareModel()
   : atoms(), eqs(atoms), 
-    pbuilder(NULL), fbuilder(NULL),
-    atom_substs(NULL), old_atoms(NULL)
+    pbuilder(nullptr), fbuilder(nullptr),
+    atom_substs(nullptr), old_atoms(nullptr)
 {
 }
 
 DynareModel::DynareModel(const DynareModel &dm)
   : atoms(dm.atoms), eqs(dm.eqs, atoms), order(dm.order),
-    param_vals(0), init_vals(0), vcov_mat(0),
+    param_vals(nullptr), init_vals(nullptr), vcov_mat(nullptr),
     t_plobjective(dm.t_plobjective),
     t_pldiscount(dm.t_pldiscount),
-    pbuilder(NULL), fbuilder(NULL),
-    atom_substs(NULL), old_atoms(NULL)
+    pbuilder(nullptr), fbuilder(nullptr),
+    atom_substs(nullptr), old_atoms(nullptr)
 {
   if (dm.param_vals)
     param_vals = new Vector((const Vector &) *(dm.param_vals));
@@ -79,7 +79,7 @@ DynareModel::get_planner_info() const
 {
   if (pbuilder)
     return &(pbuilder->get_info());
-  return NULL;
+  return nullptr;
 }
 
 const ForwSubstInfo *
@@ -87,7 +87,7 @@ DynareModel::get_forw_subst_info() const
 {
   if (fbuilder)
     return &(fbuilder->get_info());
-  return NULL;
+  return nullptr;
 }
 
 const ogp::SubstInfo *
@@ -95,7 +95,7 @@ DynareModel::get_subst_info() const
 {
   if (atom_substs)
     return &(atom_substs->get_info());
-  return NULL;
+  return nullptr;
 }
 
 void
diff --git a/dynare++/src/dynare_model.hh b/dynare++/src/dynare_model.hh
index e0b0ed9a9..3d01ebce0 100644
--- a/dynare++/src/dynare_model.hh
+++ b/dynare++/src/dynare_model.hh
@@ -84,12 +84,12 @@ namespace ogdyn
     /** A vector of parameters values created by a subclass. It
      * is stored with natural ordering (outer) of the parameters
      * given by atoms. */
-    Vector *param_vals{0};
+    Vector *param_vals{nullptr};
     /** A vector of initial values created by a subclass. It is
      * stored with internal ordering given by atoms. */
-    Vector *init_vals{0};
+    Vector *init_vals{nullptr};
     /** A matrix for vcov. It is created by a subclass. */
-    TwoDMatrix *vcov_mat{0};
+    TwoDMatrix *vcov_mat{nullptr};
     /** Tree index of the planner objective. If there was no
      * planner objective keyword, the value is set to -1. */
     int t_plobjective{-1};
diff --git a/dynare++/src/dynare_params.cc b/dynare++/src/dynare_params.cc
index c94f38ca1..297eaae2c 100644
--- a/dynare++/src/dynare_params.cc
+++ b/dynare++/src/dynare_params.cc
@@ -46,7 +46,7 @@ const char *help_str
 const char *dyn_basename(const char *str);
 
 DynareParams::DynareParams(int argc, char **argv)
-  : modname(NULL), num_per(100), num_burn(0), num_sim(80),
+  : modname(nullptr), num_per(100), num_burn(0), num_sim(80),
     num_rtper(0), num_rtsim(0),
     num_condper(0), num_condsim(0),
     num_threads(2), num_steps(0),
@@ -71,37 +71,37 @@ DynareParams::DynareParams(int argc, char **argv)
   argc--;
 
   struct option const opts [] = {
-    {"periods", required_argument, NULL, opt_per},
-    {"per", required_argument, NULL, opt_per},
-    {"burn", required_argument, NULL, opt_burn},
-    {"simulations", required_argument, NULL, opt_sim},
-    {"sim", required_argument, NULL, opt_sim},
-    {"rtperiods", required_argument, NULL, opt_rtper},
-    {"rtper", required_argument, NULL, opt_rtper},
-    {"rtsimulations", required_argument, NULL, opt_rtsim},
-    {"rtsim", required_argument, NULL, opt_rtsim},
-    {"condperiods", required_argument, NULL, opt_condper},
-    {"condper", required_argument, NULL, opt_condper},
-    {"condsimulations", required_argument, NULL, opt_condsim},
-    {"condsim", required_argument, NULL, opt_condsim},
-    {"prefix", required_argument, NULL, opt_prefix},
-    {"threads", required_argument, NULL, opt_threads},
-    {"steps", required_argument, NULL, opt_steps},
-    {"seed", required_argument, NULL, opt_seed},
-    {"order", required_argument, NULL, opt_order},
-    {"ss-tol", required_argument, NULL, opt_ss_tol},
-    {"check", required_argument, NULL, opt_check},
-    {"check-scale", required_argument, NULL, opt_check_scale},
-    {"check-evals", required_argument, NULL, opt_check_evals},
-    {"check-num", required_argument, NULL, opt_check_num},
-    {"qz-criterium", required_argument, NULL, opt_qz_criterium},
-    {"no-irfs", no_argument, NULL, opt_noirfs},
-    {"irfs", no_argument, NULL, opt_irfs},
-    {"centralize", no_argument, NULL, opt_centralize},
-    {"no-centralize", no_argument, NULL, opt_no_centralize},
-    {"help", no_argument, NULL, opt_help},
-    {"version", no_argument, NULL, opt_version},
-    {NULL, 0, NULL, 0}
+    {"periods", required_argument, nullptr, opt_per},
+    {"per", required_argument, nullptr, opt_per},
+    {"burn", required_argument, nullptr, opt_burn},
+    {"simulations", required_argument, nullptr, opt_sim},
+    {"sim", required_argument, nullptr, opt_sim},
+    {"rtperiods", required_argument, nullptr, opt_rtper},
+    {"rtper", required_argument, nullptr, opt_rtper},
+    {"rtsimulations", required_argument, nullptr, opt_rtsim},
+    {"rtsim", required_argument, nullptr, opt_rtsim},
+    {"condperiods", required_argument, nullptr, opt_condper},
+    {"condper", required_argument, nullptr, opt_condper},
+    {"condsimulations", required_argument, nullptr, opt_condsim},
+    {"condsim", required_argument, nullptr, opt_condsim},
+    {"prefix", required_argument, nullptr, opt_prefix},
+    {"threads", required_argument, nullptr, opt_threads},
+    {"steps", required_argument, nullptr, opt_steps},
+    {"seed", required_argument, nullptr, opt_seed},
+    {"order", required_argument, nullptr, opt_order},
+    {"ss-tol", required_argument, nullptr, opt_ss_tol},
+    {"check", required_argument, nullptr, opt_check},
+    {"check-scale", required_argument, nullptr, opt_check_scale},
+    {"check-evals", required_argument, nullptr, opt_check_evals},
+    {"check-num", required_argument, nullptr, opt_check_num},
+    {"qz-criterium", required_argument, nullptr, opt_qz_criterium},
+    {"no-irfs", no_argument, nullptr, opt_noirfs},
+    {"irfs", no_argument, nullptr, opt_irfs},
+    {"centralize", no_argument, nullptr, opt_centralize},
+    {"no-centralize", no_argument, nullptr, opt_no_centralize},
+    {"help", no_argument, nullptr, opt_help},
+    {"version", no_argument, nullptr, opt_version},
+    {nullptr, 0, nullptr, 0}
   };
 
   int ret;
diff --git a/dynare++/src/main.cc b/dynare++/src/main.cc
index 9169a998d..7f5667968 100644
--- a/dynare++/src/main.cc
+++ b/dynare++/src/main.cc
@@ -54,7 +54,7 @@ main(int argc, char **argv)
       FILE *mfd;
       std::string mfile1(params.basename);
       mfile1 += "_f.m";
-      if (NULL == (mfd = fopen(mfile1.c_str(), "w")))
+      if (nullptr == (mfd = fopen(mfile1.c_str(), "w")))
         {
           fprintf(stderr, "Couldn't open %s for writing.\n", mfile1.c_str());
           exit(1);
@@ -65,7 +65,7 @@ main(int argc, char **argv)
 
       std::string mfile2(params.basename);
       mfile2 += "_ff.m";
-      if (NULL == (mfd = fopen(mfile2.c_str(), "w")))
+      if (nullptr == (mfd = fopen(mfile2.c_str(), "w")))
         {
           fprintf(stderr, "Couldn't open %s for writing.\n", mfile2.c_str());
           exit(1);
@@ -77,8 +77,8 @@ main(int argc, char **argv)
       // open mat file
       std::string matfile(params.basename);
       matfile += ".mat";
-      mat_t *matfd = Mat_Create(matfile.c_str(), NULL);
-      if (matfd == NULL)
+      mat_t *matfd = Mat_Create(matfile.c_str(), nullptr);
+      if (matfd == nullptr)
         {
           fprintf(stderr, "Couldn't open %s for writing.\n", matfile.c_str());
           exit(1);
diff --git a/dynare++/sylv/cc/KronVector.hh b/dynare++/sylv/cc/KronVector.hh
index 27b957446..ed5190d16 100644
--- a/dynare++/sylv/cc/KronVector.hh
+++ b/dynare++/sylv/cc/KronVector.hh
@@ -16,7 +16,7 @@ protected:
   int n{0};
   int depth{0};
 public:
-  KronVector() : Vector((double *) 0, 0) 
+  KronVector() : Vector((double *) nullptr, 0) 
   {
   }
   KronVector(int mm, int nn, int dp); // new instance
diff --git a/dynare++/sylv/cc/QuasiTriangular.cc b/dynare++/sylv/cc/QuasiTriangular.cc
index 5b70818b5..2b0cdeac3 100644
--- a/dynare++/sylv/cc/QuasiTriangular.cc
+++ b/dynare++/sylv/cc/QuasiTriangular.cc
@@ -87,7 +87,7 @@ Diagonal::Diagonal(double *data, int d_size)
       else
         {
           // it is last column or we have zero below diagonal
-          DiagonalBlock b(jbar, true, &data[id], &data[id], NULL, NULL);
+          DiagonalBlock b(jbar, true, &data[id], &data[id], nullptr, nullptr);
           blocks.push_back(b);
         }
       jbar++;
@@ -102,8 +102,8 @@ Diagonal::Diagonal(double *data, const Diagonal &d)
   int d_size = d.getSize();
   for (const auto & dit : d)
     {
-      double *beta1 = NULL;
-      double *beta2 = NULL;
+      double *beta1 = nullptr;
+      double *beta2 = nullptr;
       int id = dit.getIndex()*(d_size+1);
       int idd = id;
       if (!dit.isReal())
@@ -157,7 +157,7 @@ Diagonal::changeBase(double *p)
       if (b.isReal())
         {
           DiagonalBlock bnew(jbar, true, &p[base], &p[base],
-                             NULL, NULL);
+                             nullptr, nullptr);
           it = bnew;
         }
       else
@@ -243,8 +243,8 @@ Diagonal::checkConsistency(diag_iter it)
       double *d2 = (*it).alpha.a2;
       (*it).alpha.a2 = (*it).alpha.a1;
       (*it).real = true;
-      (*it).beta1 = 0;
-      (*it).beta2 = 0;
+      (*it).beta1 = nullptr;
+      (*it).beta2 = nullptr;
       DiagonalBlock b(jbar+1, d2);
       blocks.insert((++it).iter(), b);
       num_real += 2;
diff --git a/dynare++/sylv/cc/QuasiTriangular.hh b/dynare++/sylv/cc/QuasiTriangular.hh
index 87378483f..b66ead9df 100644
--- a/dynare++/sylv/cc/QuasiTriangular.hh
+++ b/dynare++/sylv/cc/QuasiTriangular.hh
@@ -96,8 +96,8 @@ public:
   {
     jbar = jb;
     real = true;
-    beta1 = 0;
-    beta2 = 0;
+    beta1 = nullptr;
+    beta2 = nullptr;
   }
   DiagonalBlock(const DiagonalBlock &b)
   {
diff --git a/dynare++/sylv/cc/SchurDecomp.cc b/dynare++/sylv/cc/SchurDecomp.cc
index 6fe16e1ee..0612e176d 100644
--- a/dynare++/sylv/cc/SchurDecomp.cc
+++ b/dynare++/sylv/cc/SchurDecomp.cc
@@ -18,9 +18,9 @@ SchurDecomp::SchurDecomp(const SqSylvMatrix &m)
   lapack_int lwork = 6*rows;
   auto *const work = new double[lwork];
   lapack_int info;
-  dgees("V", "N", 0, &rows, auxt.base(), &rows, &sdim,
+  dgees("V", "N", nullptr, &rows, auxt.base(), &rows, &sdim,
         wr, wi, q->base(), &rows,
-        work, &lwork, 0, &info);
+        work, &lwork, nullptr, &info);
   delete [] work;
   delete [] wi;
   delete [] wr;
diff --git a/dynare++/sylv/cc/SylvException.cc b/dynare++/sylv/cc/SylvException.cc
index 4e2c88e26..bc8ae17a8 100644
--- a/dynare++/sylv/cc/SylvException.cc
+++ b/dynare++/sylv/cc/SylvException.cc
@@ -16,7 +16,7 @@ SylvException::SylvException(const char *f, int l, const SylvException *s)
 
 SylvException::~SylvException()
 {
-  if (source != NULL)
+  if (source != nullptr)
     {
       delete source;
     }
@@ -35,7 +35,7 @@ int
 SylvException::printMessage(char *str, int maxlen) const
 {
   int remain = maxlen;
-  if (source != NULL)
+  if (source != nullptr)
     {
       remain = source->printMessage(str, maxlen);
     }
@@ -53,7 +53,7 @@ SylvException::printMessage(char *str, int maxlen) const
 
 SylvExceptionMessage::SylvExceptionMessage(const char *f, int i,
                                            const char *mes)
-  : SylvException(f, i, NULL)
+  : SylvException(f, i, nullptr)
 {
   strcpy(message, mes);
 }
diff --git a/dynare++/sylv/cc/SylvMemory.hh b/dynare++/sylv/cc/SylvMemory.hh
index 6300c5da5..7869615dd 100644
--- a/dynare++/sylv/cc/SylvMemory.hh
+++ b/dynare++/sylv/cc/SylvMemory.hh
@@ -29,7 +29,7 @@ void operator delete[](void *p);
 
 class SylvMemoryPool
 {
-  char *base{0};
+  char *base{nullptr};
   size_t length{0};
   size_t allocated{0};
   bool stack_mode{false};
diff --git a/dynare++/sylv/cc/Vector.hh b/dynare++/sylv/cc/Vector.hh
index 4f79ca4a8..162edc543 100644
--- a/dynare++/sylv/cc/Vector.hh
+++ b/dynare++/sylv/cc/Vector.hh
@@ -19,7 +19,7 @@ class Vector
 protected:
   int len{0};
   int s{1};
-  double *data{0};
+  double *data{nullptr};
   bool destroy{false};
 public:
   Vector()  
diff --git a/dynare++/sylv/testing/MMMatrix.cc b/dynare++/sylv/testing/MMMatrix.cc
index 099eb3a5a..8a6f52823 100644
--- a/dynare++/sylv/testing/MMMatrix.cc
+++ b/dynare++/sylv/testing/MMMatrix.cc
@@ -10,7 +10,7 @@
 MMMatrixIn::MMMatrixIn(const char *fname)
 {
   FILE *fd;
-  if (NULL == (fd = fopen(fname, "r")))
+  if (nullptr == (fd = fopen(fname, "r")))
     throw MMException(string("Cannot open file ")+fname+" for reading\n");
 
   char buffer[1000];
@@ -51,7 +51,7 @@ void
 MMMatrixOut::write(const char *fname, int rows, int cols, const double *data)
 {
   FILE *fd;
-  if (NULL == (fd = fopen(fname, "w")))
+  if (nullptr == (fd = fopen(fname, "w")))
     throw MMException(string("Cannot open file ")+fname+" for writing\n");
 
   if (0 > fprintf(fd, "%%%%MatrixMarket matrix array real general\n"))
diff --git a/dynare++/tl/cc/kron_prod.cc b/dynare++/tl/cc/kron_prod.cc
index a60f8fb5d..0eb9a65aa 100644
--- a/dynare++/tl/cc/kron_prod.cc
+++ b/dynare++/tl/cc/kron_prod.cc
@@ -106,7 +106,7 @@ KronProdAll::setMat(int i, const TwoDMatrix &m)
 void
 KronProdAll::setUnit(int i, int n)
 {
-  matlist[i] = NULL;
+  matlist[i] = nullptr;
   kpd.setRC(i, n, n);
 }
 
@@ -114,7 +114,7 @@ bool
 KronProdAll::isUnit() const
 {
   int i = 0;
-  while (i < dimen() && matlist[i] == NULL)
+  while (i < dimen() && matlist[i] == nullptr)
     i++;
   return i == dimen();
 }
@@ -279,7 +279,7 @@ KronProdAll::mult(const ConstTwoDMatrix &in, TwoDMatrix &out) const
     }
 
   int c;
-  TwoDMatrix *last = NULL;
+  TwoDMatrix *last = nullptr;
 
   // perform first multiplication AI
   /* Here we have to construct $A_1\otimes I$, allocate intermediate
@@ -338,7 +338,7 @@ KronProdAll::multRows(const IntSequence &irows) const
   TL_RAISE_IF(irows.size() != dimen(),
               "Wrong length of row indices in KronProdAll::multRows");
 
-  Vector *last = NULL;
+  Vector *last = nullptr;
   ConstVector *row;
   vector<Vector *> to_delete;
   for (int i = 0; i < dimen(); i++)
diff --git a/dynare++/tl/cc/permutation.cc b/dynare++/tl/cc/permutation.cc
index 5beef335a..b5d7a5efb 100644
--- a/dynare++/tl/cc/permutation.cc
+++ b/dynare++/tl/cc/permutation.cc
@@ -80,7 +80,7 @@ PermutationSet::PermutationSet(const PermutationSet &sp, int n)
     pers(new const Permutation *[size])
 {
   for (int i = 0; i < size; i++)
-    pers[i] = NULL;
+    pers[i] = nullptr;
 
   TL_RAISE_IF(n != sp.order+1,
               "Wrong new order in PermutationSet constructor");
diff --git a/dynare++/tl/cc/sthread.cc b/dynare++/tl/cc/sthread.cc
index b867c5018..b74221928 100644
--- a/dynare++/tl/cc/sthread.cc
+++ b/dynare++/tl/cc/sthread.cc
@@ -22,7 +22,7 @@ namespace sthread
   void
   thread_traits<posix>::run(_Ctype *c)
   {
-    pthread_create(&(c->getThreadIden()), NULL, posix_thread_function, (void *) c);
+    pthread_create(&(c->getThreadIden()), nullptr, posix_thread_function, (void *) c);
   }
 
   void *posix_detach_thread_function(void *c);
@@ -42,21 +42,21 @@ namespace sthread
   void
   thread_traits<posix>::exit()
   {
-    pthread_exit(NULL);
+    pthread_exit(nullptr);
   }
 
   template <>
   void
   thread_traits<posix>::join(_Ctype *c)
   {
-    pthread_join(c->getThreadIden(), NULL);
+    pthread_join(c->getThreadIden(), nullptr);
   }
 
   template <>
   void
   mutex_traits<posix>::init(pthread_mutex_t &m)
   {
-    pthread_mutex_init(&m, NULL);
+    pthread_mutex_init(&m, nullptr);
   }
 
   template <>
@@ -77,7 +77,7 @@ namespace sthread
   void
   cond_traits<posix>::init(_Tcond &cond)
   {
-    pthread_cond_init(&cond, NULL);
+    pthread_cond_init(&cond, nullptr);
   }
 
   template <>
@@ -127,7 +127,7 @@ namespace sthread
       {
         ct->exit();
       }
-    return NULL;
+    return nullptr;
   }
 
   void *
@@ -146,7 +146,7 @@ namespace sthread
       }
     if (counter)
       counter->decrease();
-    return NULL;
+    return nullptr;
   }
 }
 #else
diff --git a/dynare++/tl/cc/sthread.hh b/dynare++/tl/cc/sthread.hh
index c932d0ea0..e705c97fd 100644
--- a/dynare++/tl/cc/sthread.hh
+++ b/dynare++/tl/cc/sthread.hh
@@ -302,7 +302,7 @@ namespace sthread
     {
       auto it = _Tparent::find(mmkey(c, id));
       if (it == _Tparent::end())
-        return NULL;
+        return nullptr;
       return &((*it).second);
     }
 
@@ -502,7 +502,7 @@ namespace sthread
   {
   public:
     condition_counter<thread_impl> *counter;
-    detach_thread() : counter(NULL)
+    detach_thread() : counter(nullptr)
     {
     }
     void
diff --git a/dynare++/tl/cc/symmetry.cc b/dynare++/tl/cc/symmetry.cc
index 6ebd71d4d..ac54b841b 100644
--- a/dynare++/tl/cc/symmetry.cc
+++ b/dynare++/tl/cc/symmetry.cc
@@ -57,7 +57,7 @@ Symmetry::isFull() const
    beginning as subordinal |symiterator|. */
 
 symiterator::symiterator(SymmetrySet &ss)
-  : s(ss), subit(NULL), subs(NULL), end_flag(false)
+  : s(ss), subit(nullptr), subs(nullptr), end_flag(false)
 {
   s.sym()[0] = 0;
   if (s.size() == 2)
diff --git a/dynare++/tl/cc/t_container.hh b/dynare++/tl/cc/t_container.hh
index bf53841c3..2ecfac8e0 100644
--- a/dynare++/tl/cc/t_container.hh
+++ b/dynare++/tl/cc/t_container.hh
@@ -144,7 +144,7 @@ public:
     if (it == m.end())
       {
         TL_RAISE("Symmetry not found in TensorContainer::get");
-        return NULL;
+        return nullptr;
       }
     else
       {
@@ -161,7 +161,7 @@ public:
     if (it == m.end())
       {
         TL_RAISE("Symmetry not found in TensorContainer::get");
-        return NULL;
+        return nullptr;
       }
     else
       {
diff --git a/dynare++/tl/cc/t_polynomial.hh b/dynare++/tl/cc/t_polynomial.hh
index cdddf8b18..6d80dca9b 100644
--- a/dynare++/tl/cc/t_polynomial.hh
+++ b/dynare++/tl/cc/t_polynomial.hh
@@ -65,7 +65,7 @@ class PowerProvider
   int nv;
 public:
   PowerProvider(const ConstVector &v)
-    : origv(v), ut(NULL), ft(NULL), nv(v.length())
+    : origv(v), ut(nullptr), ft(nullptr), nv(v.length())
   {
   }
   ~PowerProvider();
@@ -165,7 +165,7 @@ public:
     PowerProvider pwp(xval);
     for (int i = 1; i <= tp.maxdim; i++)
       {
-        const _Stype &xpow = pwp.getNext((const _Stype *) NULL);
+        const _Stype &xpow = pwp.getNext((const _Stype *) nullptr);
         for (int j = 0; j <= tp.maxdim-i; j++)
           {
             if (tp.check(Symmetry(i+j)))
@@ -255,7 +255,7 @@ public:
     PowerProvider pp(v);
     for (int d = 1; d <= maxdim; d++)
       {
-        const _Stype &p = pp.getNext((const _Stype *) NULL);
+        const _Stype &p = pp.getNext((const _Stype *) nullptr);
         Symmetry cs(d);
         if (_Tparent::check(cs))
           {
diff --git a/dynare++/tl/cc/tl_static.cc b/dynare++/tl/cc/tl_static.cc
index c15937b6f..9d3cf2ca4 100644
--- a/dynare++/tl/cc/tl_static.cc
+++ b/dynare++/tl/cc/tl_static.cc
@@ -10,9 +10,9 @@ TLStatic tls;
 
 TLStatic::TLStatic()
 {
-  ebundle = NULL;
-  pbundle = NULL;
-  ptriang = NULL;
+  ebundle = nullptr;
+  pbundle = nullptr;
+  ptriang = nullptr;
 }
 
 TLStatic::~TLStatic()
diff --git a/dynare++/tl/cc/twod_matrix.cc b/dynare++/tl/cc/twod_matrix.cc
index 7c6a2df25..38d1e885d 100644
--- a/dynare++/tl/cc/twod_matrix.cc
+++ b/dynare++/tl/cc/twod_matrix.cc
@@ -104,7 +104,7 @@ void
 TwoDMatrix::save(const char *fname) const
 {
   FILE *fd;
-  if (NULL == (fd = fopen(fname, "w")))
+  if (nullptr == (fd = fopen(fname, "w")))
     {
       TL_RAISE("Cannot open file for writing in TwoDMatrix::save");
     }
diff --git a/dynare++/tl/testing/monoms.cc b/dynare++/tl/testing/monoms.cc
index f85284281..d34042489 100644
--- a/dynare++/tl/testing/monoms.cc
+++ b/dynare++/tl/testing/monoms.cc
@@ -505,11 +505,11 @@ DenseDerivGenerator::DenseDerivGenerator(int ng, int nx, int ny, int nu,
   Monom2Vector r(g, x);
   xcont = x.deriv(maxdimen);
   rcont = r.deriv(maxdimen);
-  uxcont = NULL;
+  uxcont = nullptr;
   for (int d = 1; d <= maxdimen; d++)
     {
       ts[d-1] = g.deriv(d);
-      uts[d-1] = NULL;
+      uts[d-1] = nullptr;
     }
 }
 
diff --git a/dynare++/utils/cc/memory_file.cc b/dynare++/utils/cc/memory_file.cc
index 9c8967ffe..31f89ab1d 100644
--- a/dynare++/utils/cc/memory_file.cc
+++ b/dynare++/utils/cc/memory_file.cc
@@ -49,7 +49,7 @@ ogu::calc_pos_line_and_col(int length, const char *str, int offset,
 }
 
 MemoryFile::MemoryFile(const char *fname)
-  : len(-1), data(NULL)
+  : len(-1), data(nullptr)
 {
   FILE *fd = fopen(fname, "rb");
   if (fd)