diff --git a/src/ASPHERE/pair_line_lj.cpp b/src/ASPHERE/pair_line_lj.cpp
index c8a3e04dca..07b3ea4e9f 100644
--- a/src/ASPHERE/pair_line_lj.cpp
+++ b/src/ASPHERE/pair_line_lj.cpp
@@ -301,8 +301,7 @@ void PairLineLJ::compute(int eflag, int vflag)
         }
       }
 
-      if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                           evdwl,0.0,fpair,delx,dely,delz);
+      if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
     }
   }
 
diff --git a/src/ASPHERE/pair_tri_lj.cpp b/src/ASPHERE/pair_tri_lj.cpp
index 8585b5792b..6ed422f7a4 100644
--- a/src/ASPHERE/pair_tri_lj.cpp
+++ b/src/ASPHERE/pair_tri_lj.cpp
@@ -375,8 +375,7 @@ void PairTriLJ::compute(int eflag, int vflag)
         }
       }
 
-      if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                           evdwl,0.0,fpair,delx,dely,delz);
+      if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
     }
   }
 
diff --git a/src/BODY/fix_wall_body_polygon.cpp b/src/BODY/fix_wall_body_polygon.cpp
index ec506b15f0..e4d25e8489 100644
--- a/src/BODY/fix_wall_body_polygon.cpp
+++ b/src/BODY/fix_wall_body_polygon.cpp
@@ -337,8 +337,7 @@ void FixWallBodyPolygon::post_force(int /*vflag*/)
 
       num_contacts = 0;
       facc[0] = facc[1] = facc[2] = 0;
-      vertex_against_wall(i, wall_pos, x, f, torque, side,
-                          contact_list, num_contacts, facc);
+      vertex_against_wall(i, wall_pos, x, f, torque, side, contact_list, num_contacts, facc);
 
       if (num_contacts >= 2) {
 
diff --git a/src/BODY/pair_body_nparticle.cpp b/src/BODY/pair_body_nparticle.cpp
index 8c7c671cb8..c3e146aff0 100644
--- a/src/BODY/pair_body_nparticle.cpp
+++ b/src/BODY/pair_body_nparticle.cpp
@@ -324,8 +324,7 @@ void PairBodyNparticle::compute(int eflag, int vflag)
         }
       }
 
-      if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                           evdwl,0.0,fpair,delx,dely,delz);
+      if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
     }
   }
 
diff --git a/src/BODY/pair_body_rounded_polygon.cpp b/src/BODY/pair_body_rounded_polygon.cpp
index 23a4da7f07..14f305e7d4 100644
--- a/src/BODY/pair_body_rounded_polygon.cpp
+++ b/src/BODY/pair_body_rounded_polygon.cpp
@@ -207,8 +207,7 @@ void PairBodyRoundedPolygon::compute(int eflag, int vflag)
       if (r > radi + radj + cut_inner) continue;
 
       if (npi == 1 && npj == 1) {
-        sphere_against_sphere(i, j, delx, dely, delz, rsq,
-                            k_nij, k_naij, x, v, f, evflag);
+        sphere_against_sphere(i, j, delx, dely, delz, rsq, k_nij, k_naij, x, v, f, evflag);
         continue;
       }
 
diff --git a/src/CLASS2/pair_lj_class2.cpp b/src/CLASS2/pair_lj_class2.cpp
index 84e571436f..7762e261cd 100644
--- a/src/CLASS2/pair_lj_class2.cpp
+++ b/src/CLASS2/pair_lj_class2.cpp
@@ -397,8 +397,7 @@ void PairLJClass2::compute_outer(int eflag, int vflag)
             fpair = factor_lj*forcelj*r2inv;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,0.0,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
       }
     }
   }
diff --git a/src/COLVARS/fix_colvars.cpp b/src/COLVARS/fix_colvars.cpp
index 45e12951bb..cf20c28a7e 100644
--- a/src/COLVARS/fix_colvars.cpp
+++ b/src/COLVARS/fix_colvars.cpp
@@ -1000,7 +1000,7 @@ double FixColvars::compute_scalar()
 
 /* ---------------------------------------------------------------------- */
 /* local memory usage. approximately. */
-double FixColvars::memory_usage(void)
+double FixColvars::memory_usage()
 {
   double bytes = (double) (num_coords * (2*sizeof(int)+3*sizeof(double)));
   bytes += (double)(double) (nmax*size_one) + sizeof(this);
diff --git a/src/COMPRESS/gz_file_writer.cpp b/src/COMPRESS/gz_file_writer.cpp
index d56c389d60..cd02832cca 100644
--- a/src/COMPRESS/gz_file_writer.cpp
+++ b/src/COMPRESS/gz_file_writer.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* -*- c++ -*- ----------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -17,46 +16,41 @@
 ------------------------------------------------------------------------- */
 
 #include "gz_file_writer.h"
-#include <stdio.h>
 #include "fmt/format.h"
+#include <cstdio>
 
 using namespace LAMMPS_NS;
 
-GzFileWriter::GzFileWriter() : FileWriter(),
-    compression_level(Z_BEST_COMPRESSION),
-    gzFp(nullptr)
-{
-}
+GzFileWriter::GzFileWriter() : FileWriter(), compression_level(Z_BEST_COMPRESSION), gzFp(nullptr) {}
 
 /* ---------------------------------------------------------------------- */
 
 GzFileWriter::~GzFileWriter()
 {
-  close();
+  GzFileWriter::close();
 }
 
 /* ---------------------------------------------------------------------- */
 
 void GzFileWriter::open(const std::string &path, bool append)
 {
-    if (isopen()) return;
+  if (isopen()) return;
 
-    std::string mode;
-    if (append) {
-      mode = fmt::format("ab{}", mode, compression_level);
-    } else {
-      mode = fmt::format("wb{}", mode, compression_level);
-    }
+  std::string mode;
+  if (append) {
+    mode = fmt::format("ab{}", mode, compression_level);
+  } else {
+    mode = fmt::format("wb{}", mode, compression_level);
+  }
 
-    gzFp = gzopen(path.c_str(), mode.c_str());
+  gzFp = gzopen(path.c_str(), mode.c_str());
 
-    if (gzFp == nullptr)
-      throw FileWriterException(fmt::format("Could not open file '{}'", path));
+  if (gzFp == nullptr) throw FileWriterException(fmt::format("Could not open file '{}'", path));
 }
 
 /* ---------------------------------------------------------------------- */
 
-size_t GzFileWriter::write(const void * buffer, size_t length)
+size_t GzFileWriter::write(const void *buffer, size_t length)
 {
   if (!isopen()) return 0;
 
@@ -76,7 +70,7 @@ void GzFileWriter::flush()
 
 void GzFileWriter::close()
 {
-  if (!isopen()) return;
+  if (!GzFileWriter::isopen()) return;
 
   gzclose(gzFp);
   gzFp = nullptr;
@@ -100,7 +94,8 @@ void GzFileWriter::setCompressionLevel(int level)
   const int max_level = Z_BEST_COMPRESSION;
 
   if (level < min_level || level > max_level)
-    throw FileWriterException(fmt::format("Compression level must in the range of [{}, {}]", min_level, max_level));
+    throw FileWriterException(
+        fmt::format("Compression level must in the range of [{}, {}]", min_level, max_level));
 
   compression_level = level;
 }
diff --git a/src/COMPRESS/zstd_file_writer.cpp b/src/COMPRESS/zstd_file_writer.cpp
index 609a78b216..c628cc0078 100644
--- a/src/COMPRESS/zstd_file_writer.cpp
+++ b/src/COMPRESS/zstd_file_writer.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* -*- c++ -*- ----------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -19,16 +18,13 @@
 #ifdef LAMMPS_ZSTD
 
 #include "zstd_file_writer.h"
-#include <stdio.h>
 #include "fmt/format.h"
+#include <cstdio>
 
 using namespace LAMMPS_NS;
 
-ZstdFileWriter::ZstdFileWriter() : FileWriter(),
-    compression_level(0),
-    checksum_flag(1),
-    cctx(nullptr),
-    fp(nullptr)
+ZstdFileWriter::ZstdFileWriter() :
+    FileWriter(), compression_level(0), checksum_flag(1), cctx(nullptr), fp(nullptr)
 {
   out_buffer_size = ZSTD_CStreamOutSize();
   out_buffer = new char[out_buffer_size];
@@ -38,9 +34,9 @@ ZstdFileWriter::ZstdFileWriter() : FileWriter(),
 
 ZstdFileWriter::~ZstdFileWriter()
 {
-  close();
+  ZstdFileWriter::close();
 
-  delete [] out_buffer;
+  delete[] out_buffer;
   out_buffer = nullptr;
   out_buffer_size = 0;
 }
@@ -49,41 +45,39 @@ ZstdFileWriter::~ZstdFileWriter()
 
 void ZstdFileWriter::open(const std::string &path, bool append)
 {
-    if (isopen()) return;
+  if (isopen()) return;
 
-    if (append) {
-      fp = fopen(path.c_str(), "ab");
-    } else {
-      fp = fopen(path.c_str(), "wb");
-    }
+  if (append) {
+    fp = fopen(path.c_str(), "ab");
+  } else {
+    fp = fopen(path.c_str(), "wb");
+  }
 
-    if (!fp) {
-        throw FileWriterException(fmt::format("Could not open file '{}'", path));
-    }
+  if (!fp) { throw FileWriterException(fmt::format("Could not open file '{}'", path)); }
 
-    cctx = ZSTD_createCCtx();
+  cctx = ZSTD_createCCtx();
 
-    if (!cctx) {
-        fclose(fp);
-        fp = nullptr;
-        throw FileWriterException("Could not create Zstd context");
-    }
+  if (!cctx) {
+    fclose(fp);
+    fp = nullptr;
+    throw FileWriterException("Could not create Zstd context");
+  }
 
-    ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, compression_level);
-    ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, checksum_flag);
+  ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, compression_level);
+  ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, checksum_flag);
 }
 
 /* ---------------------------------------------------------------------- */
 
-size_t ZstdFileWriter::write(const void * buffer, size_t length)
+size_t ZstdFileWriter::write(const void *buffer, size_t length)
 {
   if (!isopen()) return 0;
 
-  ZSTD_inBuffer input = { buffer, length, 0 };
+  ZSTD_inBuffer input = {buffer, length, 0};
   ZSTD_EndDirective mode = ZSTD_e_continue;
 
   do {
-    ZSTD_outBuffer output = { out_buffer, out_buffer_size, 0 };
+    ZSTD_outBuffer output = {out_buffer, out_buffer_size, 0};
     ZSTD_compressStream2(cctx, &output, &input, mode);
     fwrite(out_buffer, sizeof(char), output.pos, fp);
   } while (input.pos < input.size);
@@ -98,11 +92,11 @@ void ZstdFileWriter::flush()
   if (!isopen()) return;
 
   size_t remaining;
-  ZSTD_inBuffer input = { nullptr, 0, 0 };
+  ZSTD_inBuffer input = {nullptr, 0, 0};
   ZSTD_EndDirective mode = ZSTD_e_flush;
 
   do {
-    ZSTD_outBuffer output = { out_buffer, out_buffer_size, 0 };
+    ZSTD_outBuffer output = {out_buffer, out_buffer_size, 0};
     remaining = ZSTD_compressStream2(cctx, &output, &input, mode);
     fwrite(out_buffer, sizeof(char), output.pos, fp);
   } while (remaining);
@@ -114,14 +108,14 @@ void ZstdFileWriter::flush()
 
 void ZstdFileWriter::close()
 {
-  if (!isopen()) return;
+  if (!ZstdFileWriter::isopen()) return;
 
   size_t remaining;
-  ZSTD_inBuffer input = { nullptr, 0, 0 };
+  ZSTD_inBuffer input = {nullptr, 0, 0};
   ZSTD_EndDirective mode = ZSTD_e_end;
 
   do {
-    ZSTD_outBuffer output = { out_buffer, out_buffer_size, 0 };
+    ZSTD_outBuffer output = {out_buffer, out_buffer_size, 0};
     remaining = ZSTD_compressStream2(cctx, &output, &input, mode);
     fwrite(out_buffer, sizeof(char), output.pos, fp);
   } while (remaining);
@@ -150,7 +144,8 @@ void ZstdFileWriter::setCompressionLevel(int level)
   const int max_level = ZSTD_maxCLevel();
 
   if (level < min_level || level > max_level)
-    throw FileWriterException(fmt::format("Compression level must in the range of [{}, {}]", min_level, max_level));
+    throw FileWriterException(
+        fmt::format("Compression level must in the range of [{}, {}]", min_level, max_level));
 
   compression_level = level;
 }
@@ -159,8 +154,7 @@ void ZstdFileWriter::setCompressionLevel(int level)
 
 void ZstdFileWriter::setChecksum(bool enabled)
 {
-  if (isopen())
-    throw FileWriterException("Checksum flag can not be changed while file is open");
+  if (isopen()) throw FileWriterException("Checksum flag can not be changed while file is open");
   checksum_flag = enabled ? 1 : 0;
 }
 
diff --git a/src/DIELECTRIC/compute_efield_atom.cpp b/src/DIELECTRIC/compute_efield_atom.cpp
index c6ea0db94f..e5626c9c6c 100644
--- a/src/DIELECTRIC/compute_efield_atom.cpp
+++ b/src/DIELECTRIC/compute_efield_atom.cpp
@@ -38,7 +38,7 @@ using namespace LAMMPS_NS;
 /* ---------------------------------------------------------------------- */
 
 ComputeEfieldAtom::ComputeEfieldAtom(LAMMPS *lmp, int narg, char **arg) :
-  Compute(lmp, narg, arg), efield(NULL)
+  Compute(lmp, narg, arg), efield(nullptr)
 {
   if (narg < 3) error->all(FLERR,"Illegal compute efield/atom command");
 
diff --git a/src/DIELECTRIC/fix_polarize_bem_gmres.cpp b/src/DIELECTRIC/fix_polarize_bem_gmres.cpp
index 62febf13c2..2ea5536722 100644
--- a/src/DIELECTRIC/fix_polarize_bem_gmres.cpp
+++ b/src/DIELECTRIC/fix_polarize_bem_gmres.cpp
@@ -69,8 +69,8 @@ using namespace MathConst;
 /* ---------------------------------------------------------------------- */
 
 FixPolarizeBEMGMRES::FixPolarizeBEMGMRES(LAMMPS *lmp, int narg, char **arg) :
-    Fix(lmp, narg, arg), q_backup(NULL), c(NULL), g(NULL), h(NULL), r(NULL), s(NULL), v(NULL),
-    y(NULL)
+    Fix(lmp, narg, arg), q_backup(nullptr), c(nullptr), g(nullptr), h(nullptr), r(nullptr), s(nullptr), v(nullptr),
+    y(nullptr)
 {
   if (narg < 5) error->all(FLERR, "Illegal fix polarize/bem/gmres command");
 
@@ -110,7 +110,7 @@ FixPolarizeBEMGMRES::FixPolarizeBEMGMRES(LAMMPS *lmp, int narg, char **arg) :
   if (atom->torque_flag) torqueflag = 1;
   if (atom->avec->forceclearflag) extraflag = 1;
 
-  grow_arrays(atom->nmax);
+  FixPolarizeBEMGMRES::grow_arrays(atom->nmax);
   atom->add_callback(0);    // to ensure to work with atom->sort()
 
   // output the residual and actual number of iterations
@@ -133,7 +133,7 @@ FixPolarizeBEMGMRES::~FixPolarizeBEMGMRES()
   memory->destroy(mat2tag);
   memory->destroy(tag2mat);
 
-  if (allocated) deallocate();
+  if (allocated) FixPolarizeBEMGMRES::deallocate();
   atom->delete_callback(id, 0);
 }
 
diff --git a/src/DIELECTRIC/fix_polarize_functional.cpp b/src/DIELECTRIC/fix_polarize_functional.cpp
index 84f68e79b1..34c1ba2f60 100644
--- a/src/DIELECTRIC/fix_polarize_functional.cpp
+++ b/src/DIELECTRIC/fix_polarize_functional.cpp
@@ -131,7 +131,7 @@ FixPolarizeFunctional::FixPolarizeFunctional(LAMMPS *lmp, int narg, char **arg)
   cg_r = cg_p = cg_Ap = nullptr;
   cg_A = nullptr;
 
-  grow_arrays(atom->nmax);
+  FixPolarizeFunctional::grow_arrays(atom->nmax);
   atom->add_callback(0);    // to ensure to work with atom->sort()
 }
 
diff --git a/src/DIELECTRIC/pair_coul_long_dielectric.cpp b/src/DIELECTRIC/pair_coul_long_dielectric.cpp
index fd5110cdb6..a079c3abf7 100644
--- a/src/DIELECTRIC/pair_coul_long_dielectric.cpp
+++ b/src/DIELECTRIC/pair_coul_long_dielectric.cpp
@@ -221,10 +221,10 @@ void PairCoulLongDielectric::init_style()
 
   // insure use of KSpace long-range solver, set g_ewald
 
-  if (force->kspace == NULL) error->all(FLERR, "Pair style requires a KSpace style");
+  if (force->kspace == nullptr) error->all(FLERR, "Pair style requires a KSpace style");
   g_ewald = force->kspace->g_ewald;
 
   // setup force tables
 
-  if (ncoultablebits) init_tables(cut_coul, NULL);
+  if (ncoultablebits) init_tables(cut_coul, nullptr);
 }
diff --git a/src/DIELECTRIC/pair_lj_cut_coul_debye_dielectric.cpp b/src/DIELECTRIC/pair_lj_cut_coul_debye_dielectric.cpp
index 4f3b46b14d..8c90e1f84b 100644
--- a/src/DIELECTRIC/pair_lj_cut_coul_debye_dielectric.cpp
+++ b/src/DIELECTRIC/pair_lj_cut_coul_debye_dielectric.cpp
@@ -40,8 +40,8 @@ using namespace MathConst;
 
 PairLJCutCoulDebyeDielectric::PairLJCutCoulDebyeDielectric(LAMMPS *lmp) : PairLJCutCoulDebye(lmp)
 {
-  efield = NULL;
-  epot = NULL;
+  efield = nullptr;
+  epot = nullptr;
   nmax = 0;
 }
 
diff --git a/src/DIELECTRIC/pair_lj_cut_coul_long_dielectric.cpp b/src/DIELECTRIC/pair_lj_cut_coul_long_dielectric.cpp
index 7f5b67a22b..bbb8bba728 100644
--- a/src/DIELECTRIC/pair_lj_cut_coul_long_dielectric.cpp
+++ b/src/DIELECTRIC/pair_lj_cut_coul_long_dielectric.cpp
@@ -257,7 +257,7 @@ void PairLJCutCoulLongDielectric::init_style()
 
   // insure use of KSpace long-range solver, set g_ewald
 
-  if (force->kspace == NULL) error->all(FLERR, "Pair style requires a KSpace style");
+  if (force->kspace == nullptr) error->all(FLERR, "Pair style requires a KSpace style");
   g_ewald = force->kspace->g_ewald;
 
   // setup force tables
diff --git a/src/DIELECTRIC/pair_lj_cut_coul_msm_dielectric.cpp b/src/DIELECTRIC/pair_lj_cut_coul_msm_dielectric.cpp
index 5fd8b499f8..e22ee4b665 100644
--- a/src/DIELECTRIC/pair_lj_cut_coul_msm_dielectric.cpp
+++ b/src/DIELECTRIC/pair_lj_cut_coul_msm_dielectric.cpp
@@ -365,7 +365,7 @@ void PairLJCutCoulMSMDielectric::init_style()
 
   // insure use of KSpace long-range solver, set g_ewald
 
-  if (force->kspace == NULL) error->all(FLERR, "Pair style requires a KSpace style");
+  if (force->kspace == nullptr) error->all(FLERR, "Pair style requires a KSpace style");
   g_ewald = force->kspace->g_ewald;
 
   // setup force tables
@@ -382,5 +382,5 @@ void *PairLJCutCoulMSMDielectric::extract(const char *str, int &dim)
   dim = 2;
   if (strcmp(str, "epsilon") == 0) return (void *) epsilon;
   if (strcmp(str, "sigma") == 0) return (void *) sigma;
-  return NULL;
+  return nullptr;
 }
diff --git a/src/DPD-REACT/fix_rx.cpp b/src/DPD-REACT/fix_rx.cpp
index 91eb3f54df..a37a6ad7b6 100644
--- a/src/DPD-REACT/fix_rx.cpp
+++ b/src/DPD-REACT/fix_rx.cpp
@@ -59,7 +59,7 @@ namespace /* anonymous */
 {
 
 typedef double TimerType;
-TimerType getTimeStamp(void) { return MPI_Wtime(); }
+TimerType getTimeStamp() { return MPI_Wtime(); }
 double getElapsedTime( const TimerType &t0, const TimerType &t1) { return t1-t0; }
 
 } // end namespace
@@ -1246,7 +1246,7 @@ int FixRX::rkf45_h0 (const int neq, const double t, const double /*t_stop*/,
    return (iter + 1);
 }
 
-void FixRX::odeDiagnostics(void)
+void FixRX::odeDiagnostics()
 {
   TimerType timer_start = getTimeStamp();
 
diff --git a/src/DPD-SMOOTH/fix_meso_move.cpp b/src/DPD-SMOOTH/fix_meso_move.cpp
index 85eee5ffbe..ba32962b3c 100644
--- a/src/DPD-SMOOTH/fix_meso_move.cpp
+++ b/src/DPD-SMOOTH/fix_meso_move.cpp
@@ -224,7 +224,7 @@ FixMesoMove::FixMesoMove (LAMMPS *lmp, int narg, char **arg) :
   // perform initial allocation of atom-based array
   // register with Atom class
 
-  grow_arrays(atom->nmax);
+  FixMesoMove::grow_arrays(atom->nmax);
   atom->add_callback(Atom::GROW);
   atom->add_callback(Atom::RESTART);
 
diff --git a/src/DRUDE/fix_drude.cpp b/src/DRUDE/fix_drude.cpp
index e0b313c35e..39b0158e06 100644
--- a/src/DRUDE/fix_drude.cpp
+++ b/src/DRUDE/fix_drude.cpp
@@ -55,7 +55,7 @@ FixDrude::FixDrude(LAMMPS *lmp, int narg, char **arg) :
   }
 
   drudeid = nullptr;
-  grow_arrays(atom->nmax);
+  FixDrude::grow_arrays(atom->nmax);
   atom->add_callback(Atom::GROW);
   atom->add_callback(Atom::RESTART);
   atom->add_callback(Atom::BORDER);
@@ -516,7 +516,8 @@ void FixDrude::ring_copy_drude(int size, char *cbuf, void *ptr) {
  * ----------------------------------------------------------------------*/
 void FixDrude::set_arrays(int i) {
     if (drudetype[atom->type[i]] != NOPOL_TYPE) {
-        if (atom->nspecial[i] ==0) error->all(FLERR, "Polarizable atoms cannot be inserted with special lists info from the molecule template");
+        if (atom->nspecial[i] == nullptr)
+          error->all(FLERR, "Polarizable atoms cannot be inserted with special lists info from the molecule template");
         drudeid[i] = atom->special[i][0]; // Drude partner should be at first place in the special list
     } else {
         drudeid[i] = 0;
diff --git a/src/EXTRA-FIX/fix_flow_gauss.cpp b/src/EXTRA-FIX/fix_flow_gauss.cpp
index 1a48488ab6..415f1eecc0 100644
--- a/src/EXTRA-FIX/fix_flow_gauss.cpp
+++ b/src/EXTRA-FIX/fix_flow_gauss.cpp
@@ -84,14 +84,14 @@ FixFlowGauss::FixFlowGauss(LAMMPS *lmp, int narg, char **arg) :
 
   // by default, do not compute work done
 
-  workflag=0;
+  workflag=false;
 
   // process optional keyword
   int iarg = 6;
   while (iarg < narg) {
     if (strcmp(arg[iarg],"energy") == 0) {
       if (iarg+2 > narg) error->all(FLERR,"Illegal energy keyword");
-      if (strcmp(arg[iarg+1],"yes") == 0) workflag = 1;
+      if (strcmp(arg[iarg+1],"yes") == 0) workflag = true;
       else if (strcmp(arg[iarg+1],"no") != 0)
         error->all(FLERR,"Illegal energy keyword");
       iarg += 2;
@@ -139,7 +139,7 @@ void FixFlowGauss::setup(int vflag)
 {
   // need to compute work done if fix_modify energy yes is set
 
-  if (thermo_energy) workflag = 1;
+  if (thermo_energy) workflag = true;
 
   // get total mass of group
 
diff --git a/src/EXTRA-FIX/fix_ttm_grid.cpp b/src/EXTRA-FIX/fix_ttm_grid.cpp
index cbefc09aef..accc792b4a 100644
--- a/src/EXTRA-FIX/fix_ttm_grid.cpp
+++ b/src/EXTRA-FIX/fix_ttm_grid.cpp
@@ -366,7 +366,7 @@ void FixTTMGrid::write_electron_temperatures(const std::string &filename)
                update->unit_style, nxgrid, nygrid, nzgrid, update->ntimestep, style);
   }
 
-  gc->gather(GridComm::FIX, this, 1, sizeof(double), 1, NULL, MPI_DOUBLE);
+  gc->gather(GridComm::FIX, this, 1, sizeof(double), 1, nullptr, MPI_DOUBLE);
 
   if (comm->me == 0) fclose(FPout);
 }
diff --git a/src/EXTRA-FIX/fix_ttm_mod.cpp b/src/EXTRA-FIX/fix_ttm_mod.cpp
index 905232ff08..cec97bd280 100644
--- a/src/EXTRA-FIX/fix_ttm_mod.cpp
+++ b/src/EXTRA-FIX/fix_ttm_mod.cpp
@@ -101,7 +101,7 @@ FixTTMMod::FixTTMMod(LAMMPS *lmp, int narg, char **arg) :
   nzgrid = utils::inumeric(FLERR,arg[7],false,lmp);
 
   double tinit = 0.0;
-  infile = outfile = NULL;
+  infile = outfile = nullptr;
 
   int iarg = 8;
   while (iarg < narg) {
diff --git a/src/EXTRA-PAIR/pair_lj96_cut.cpp b/src/EXTRA-PAIR/pair_lj96_cut.cpp
index b20ebf2c88..a762e7de6b 100644
--- a/src/EXTRA-PAIR/pair_lj96_cut.cpp
+++ b/src/EXTRA-PAIR/pair_lj96_cut.cpp
@@ -376,8 +376,7 @@ void PairLJ96Cut::compute_outer(int eflag, int vflag)
           r2inv = 1.0/rsq;
           r6inv = r2inv*r2inv*r2inv;
           r3inv = sqrt(r6inv);
-          evdwl = r6inv*(lj3[itype][jtype]*r3inv-lj4[itype][jtype]) -
-            offset[itype][jtype];
+          evdwl = r6inv*(lj3[itype][jtype]*r3inv-lj4[itype][jtype]) - offset[itype][jtype];
           evdwl *= factor_lj;
         }
 
@@ -392,8 +391,7 @@ void PairLJ96Cut::compute_outer(int eflag, int vflag)
             fpair = factor_lj*forcelj*r2inv;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,0.0,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
       }
     }
   }
diff --git a/src/EXTRA-PAIR/pair_lj_expand_coul_long.cpp b/src/EXTRA-PAIR/pair_lj_expand_coul_long.cpp
index 685871db3b..2791c28747 100644
--- a/src/EXTRA-PAIR/pair_lj_expand_coul_long.cpp
+++ b/src/EXTRA-PAIR/pair_lj_expand_coul_long.cpp
@@ -195,14 +195,12 @@ void PairLJExpandCoulLong::compute(int eflag, int vflag)
           } else ecoul = 0.0;
 
           if (rsq < cut_ljsq[itype][jtype]) {
-            evdwl = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]) -
-              offset[itype][jtype];
+            evdwl = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]) - offset[itype][jtype];
             evdwl *= factor_lj;
           } else evdwl = 0.0;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,ecoul,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,ecoul,fpair,delx,dely,delz);
       }
     }
   }
@@ -980,8 +978,7 @@ double PairLJExpandCoulLong::single(int i, int j, int itype, int jtype,
   }
 
   if (rsq < cut_ljsq[itype][jtype]) {
-    philj = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]) -
-      offset[itype][jtype];
+    philj = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]) - offset[itype][jtype];
     eng += factor_lj*philj;
   }
 
diff --git a/src/EXTRA-PAIR/pair_lj_gromacs_coul_gromacs.cpp b/src/EXTRA-PAIR/pair_lj_gromacs_coul_gromacs.cpp
index 9db42342d9..96b8985b6b 100644
--- a/src/EXTRA-PAIR/pair_lj_gromacs_coul_gromacs.cpp
+++ b/src/EXTRA-PAIR/pair_lj_gromacs_coul_gromacs.cpp
@@ -164,16 +164,14 @@ void PairLJGromacsCoulGromacs::compute(int eflag, int vflag)
             evdwl = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]);
             evdwl += ljsw5[itype][jtype];
             if (rsq > cut_lj_innersq) {
-              eswitch = tlj*tlj*tlj *
-                (ljsw3[itype][jtype] + ljsw4[itype][jtype]*tlj);
+              eswitch = tlj*tlj*tlj * (ljsw3[itype][jtype] + ljsw4[itype][jtype]*tlj);
               evdwl += eswitch;
             }
             evdwl *= factor_lj;
           } else evdwl = 0.0;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,ecoul,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,ecoul,fpair,delx,dely,delz);
       }
     }
   }
@@ -487,8 +485,7 @@ double PairLJGromacsCoulGromacs::single(int i, int j, int itype, int jtype,
   if (rsq < cut_coulsq) {
     phicoul = force->qqrd2e * atom->q[i]*atom->q[j] * (sqrt(r2inv)-coulsw5);
     if (rsq > cut_coul_innersq) {
-      phiswitchcoul = force->qqrd2e * atom->q[i]*atom->q[j] *
-        tc*tc*tc * (coulsw3 + coulsw4*tc);
+      phiswitchcoul = force->qqrd2e * atom->q[i]*atom->q[j] * tc*tc*tc * (coulsw3 + coulsw4*tc);
       phicoul += phiswitchcoul;
     }
     eng += factor_coul*phicoul;
@@ -498,8 +495,7 @@ double PairLJGromacsCoulGromacs::single(int i, int j, int itype, int jtype,
     philj = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]);
     philj += ljsw5[itype][jtype];
     if (rsq > cut_lj_innersq) {
-      phiswitch = tlj*tlj*tlj *
-        (ljsw3[itype][jtype] + ljsw4[itype][jtype]*tlj);
+      phiswitch = tlj*tlj*tlj * (ljsw3[itype][jtype] + ljsw4[itype][jtype]*tlj);
       philj += phiswitch;
     }
     eng += factor_lj*philj;
diff --git a/src/EXTRA-PAIR/pair_lj_relres.cpp b/src/EXTRA-PAIR/pair_lj_relres.cpp
index 1ea3684171..5d1ed4fdf0 100644
--- a/src/EXTRA-PAIR/pair_lj_relres.cpp
+++ b/src/EXTRA-PAIR/pair_lj_relres.cpp
@@ -183,15 +183,13 @@ void PairLJRelRes::compute(int eflag, int vflag)
 
         if (eflag) {
           if (rsq < cutf_inner_sq[itype][jtype]) {
-            evdwl = r6inv*(ljf3[itype][jtype]*r6inv-
-                           ljf4[itype][jtype])-offsetsm[itype][jtype];
+            evdwl = r6inv*(ljf3[itype][jtype]*r6inv-ljf4[itype][jtype])-offsetsm[itype][jtype];
           } else if (rsq < cutfsq[itype][jtype]) {
             evdwl = ljswf0[itype][jtype]-ljswf1[itype][jtype]*t-
               ljswf2[itype][jtype]*tsq/2.0-ljswf3[itype][jtype]*tsq*t/3.0-
               ljswf4[itype][jtype]*tsq*tsq/4.0-offsetsp[itype][jtype];
           } else if (rsq < cut_inner_sq[itype][jtype]) {
-            evdwl = r6inv*(lj3[itype][jtype]*r6inv-
-                           lj4[itype][jtype])-offset[itype][jtype];
+            evdwl = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype])-offset[itype][jtype];
           } else {
             evdwl = ljsw0[itype][jtype]-ljsw1[itype][jtype]*t-
               ljsw2[itype][jtype]*tsq/2.0-ljsw3[itype][jtype]*tsq*t/3.0-
@@ -200,8 +198,7 @@ void PairLJRelRes::compute(int eflag, int vflag)
           evdwl *= factor_lj;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,0.0,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
       }
     }
   }
@@ -726,15 +723,13 @@ double PairLJRelRes::single(int /*i*/, int /*j*/, int itype, int jtype,
   fforce = factor_lj*forcelj*r2inv;
 
   if (rsq < cutf_inner_sq[itype][jtype]) {
-    philj = r6inv*(ljf3[itype][jtype]*r6inv-
-                   ljf4[itype][jtype])-offsetsm[itype][jtype];
+    philj = r6inv*(ljf3[itype][jtype]*r6inv-ljf4[itype][jtype])-offsetsm[itype][jtype];
   } else if (rsq < cutfsq[itype][jtype]) {
     philj = ljswf0[itype][jtype]-ljswf1[itype][jtype]*t-
       ljswf2[itype][jtype]*tsq/2.0-ljswf3[itype][jtype]*tsq*t/3.0-
       ljswf4[itype][jtype]*tsq*tsq/4.0-offsetsp[itype][jtype];
   } else if (rsq < cut_inner_sq[itype][jtype]) {
-    philj = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]) -
-      offset[itype][jtype];
+    philj = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]) - offset[itype][jtype];
   } else {
     philj = ljsw0[itype][jtype] - ljsw1[itype][jtype]*t -
       ljsw2[itype][jtype]*tsq/2.0 - ljsw3[itype][jtype]*tsq*t/3.0 -
diff --git a/src/EXTRA-PAIR/pair_lj_smooth.cpp b/src/EXTRA-PAIR/pair_lj_smooth.cpp
index f1aba212a3..5346a39e62 100644
--- a/src/EXTRA-PAIR/pair_lj_smooth.cpp
+++ b/src/EXTRA-PAIR/pair_lj_smooth.cpp
@@ -136,8 +136,7 @@ void PairLJSmooth::compute(int eflag, int vflag)
 
         if (eflag) {
           if (rsq < cut_inner_sq[itype][jtype])
-            evdwl = r6inv * (lj3[itype][jtype]*r6inv -
-                             lj4[itype][jtype]) - offset[itype][jtype];
+            evdwl = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]) - offset[itype][jtype];
           else
             evdwl = ljsw0[itype][jtype] - ljsw1[itype][jtype]*t -
               ljsw2[itype][jtype]*tsq/2.0 - ljsw3[itype][jtype]*tsq*t/3.0 -
@@ -145,8 +144,7 @@ void PairLJSmooth::compute(int eflag, int vflag)
           evdwl *= factor_lj;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,0.0,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
       }
     }
   }
@@ -446,8 +444,7 @@ double PairLJSmooth::single(int /*i*/, int /*j*/, int itype, int jtype, double r
   fforce = factor_lj*forcelj*r2inv;
 
   if (rsq < cut_inner_sq[itype][jtype])
-    philj = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]) -
-      offset[itype][jtype];
+    philj = r6inv * (lj3[itype][jtype]*r6inv - lj4[itype][jtype]) - offset[itype][jtype];
   else
     philj = ljsw0[itype][jtype] - ljsw1[itype][jtype]*t -
       ljsw2[itype][jtype]*tsq/2.0 - ljsw3[itype][jtype]*tsq*t/3.0 -
diff --git a/src/EXTRA-PAIR/pair_nm_cut_coul_cut.cpp b/src/EXTRA-PAIR/pair_nm_cut_coul_cut.cpp
index 6c2dd433de..a0e31d3070 100644
--- a/src/EXTRA-PAIR/pair_nm_cut_coul_cut.cpp
+++ b/src/EXTRA-PAIR/pair_nm_cut_coul_cut.cpp
@@ -147,17 +147,13 @@ void PairNMCutCoulCut::compute(int eflag, int vflag)
             ecoul = factor_coul * qqrd2e * qtmp*q[j]*sqrt(r2inv);
           else ecoul = 0.0;
           if (rsq < cut_ljsq[itype][jtype]) {
-            evdwl = e0nm[itype][jtype]*(mm[itype][jtype] *
-                                        r0n[itype][jtype]*rninv -
-                                        nn[itype][jtype] *
-                                        r0m[itype][jtype]*rminv) -
-              offset[itype][jtype];
+            evdwl = e0nm[itype][jtype]*(mm[itype][jtype] * r0n[itype][jtype]*rninv -
+                                        nn[itype][jtype] * r0m[itype][jtype]*rminv) - offset[itype][jtype];
             evdwl *= factor_lj;
           } else evdwl = 0.0;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,ecoul,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,ecoul,fpair,delx,dely,delz);
       }
     }
   }
diff --git a/src/FEP/pair_lj_cut_coul_long_soft.cpp b/src/FEP/pair_lj_cut_coul_long_soft.cpp
index 0d81fb17cd..0e43e72a17 100644
--- a/src/FEP/pair_lj_cut_coul_long_soft.cpp
+++ b/src/FEP/pair_lj_cut_coul_long_soft.cpp
@@ -178,8 +178,7 @@ void PairLJCutCoulLongSoft::compute(int eflag, int vflag)
           } else evdwl = 0.0;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,ecoul,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,ecoul,fpair,delx,dely,delz);
       }
     }
   }
diff --git a/src/FEP/pair_lj_cut_soft.cpp b/src/FEP/pair_lj_cut_soft.cpp
index 0934a91255..e4c2d19e95 100644
--- a/src/FEP/pair_lj_cut_soft.cpp
+++ b/src/FEP/pair_lj_cut_soft.cpp
@@ -410,8 +410,7 @@ void PairLJCutSoft::compute_outer(int eflag, int vflag)
             fpair = factor_lj*forcelj;
         }
 
-        if (evflag) ev_tally(i,j,nlocal,newton_pair,
-                             evdwl,0.0,fpair,delx,dely,delz);
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,fpair,delx,dely,delz);
       }
     }
   }
diff --git a/src/KSPACE/fft3d.cpp b/src/KSPACE/fft3d.cpp
index 130aaebf21..d35028f280 100644
--- a/src/KSPACE/fft3d.cpp
+++ b/src/KSPACE/fft3d.cpp
@@ -308,10 +308,9 @@ struct fft_plan_3d *fft_3d_create_plan(
     first_jhi = (ip1+1)*nmid/np1 - 1;
     first_klo = ip2*nslow/np2;
     first_khi = (ip2+1)*nslow/np2 - 1;
-    plan->pre_plan =
-      remap_3d_create_plan(comm,in_ilo,in_ihi,in_jlo,in_jhi,in_klo,in_khi,
-                           first_ilo,first_ihi,first_jlo,first_jhi,
-                           first_klo,first_khi,2,0,0,FFT_PRECISION,0);
+    plan->pre_plan = remap_3d_create_plan(comm,in_ilo,in_ihi,in_jlo,in_jhi,in_klo,in_khi,
+                                          first_ilo,first_ihi,first_jlo,first_jhi,
+                                          first_klo,first_khi,2,0,0,FFT_PRECISION,0);
     if (plan->pre_plan == nullptr) return nullptr;
   }
 
@@ -330,13 +329,10 @@ struct fft_plan_3d *fft_3d_create_plan(
   second_jhi = nmid - 1;
   second_klo = ip2*nslow/np2;
   second_khi = (ip2+1)*nslow/np2 - 1;
-  plan->mid1_plan =
-      remap_3d_create_plan(comm,
-                           first_ilo,first_ihi,first_jlo,first_jhi,
-                           first_klo,first_khi,
-                           second_ilo,second_ihi,second_jlo,second_jhi,
-                           second_klo,second_khi,2,1,0,FFT_PRECISION,
-                           usecollective);
+  plan->mid1_plan = remap_3d_create_plan(comm, first_ilo,first_ihi,first_jlo,first_jhi,
+                                         first_klo,first_khi,second_ilo,second_ihi,
+                                         second_jlo,second_jhi,second_klo,second_khi,
+                                         2,1,0,FFT_PRECISION,usecollective);
   if (plan->mid1_plan == nullptr) return nullptr;
 
   // 1d FFTs along mid axis
diff --git a/src/MANYBODY/pair_eam_fs.cpp b/src/MANYBODY/pair_eam_fs.cpp
index b4596a297b..cf552995d0 100644
--- a/src/MANYBODY/pair_eam_fs.cpp
+++ b/src/MANYBODY/pair_eam_fs.cpp
@@ -125,8 +125,6 @@ void PairEAMFS::read_file(char *filename)
 
     // transparently convert units for supported conversions
 
-    // transparently convert units for supported conversions
-
     int unit_convert = reader.get_unit_convert();
     double conversion_factor = utils::get_conversion_factor(utils::ENERGY,
                                                             unit_convert);
diff --git a/src/MDI/fix_mdi_engine.cpp b/src/MDI/fix_mdi_engine.cpp
index a898647563..4c8e9cccf4 100644
--- a/src/MDI/fix_mdi_engine.cpp
+++ b/src/MDI/fix_mdi_engine.cpp
@@ -32,8 +32,8 @@
 #include "update.h"
 #include "verlet.h"
 
+#include <cstring>
 #include <limits>
-#include <string.h>
 
 enum { NONE, REAL, METAL };    // LAMMPS units which MDI supports
 
diff --git a/src/MDI/mdi_engine.cpp b/src/MDI/mdi_engine.cpp
index 9bd9258dfc..f1143fbe28 100644
--- a/src/MDI/mdi_engine.cpp
+++ b/src/MDI/mdi_engine.cpp
@@ -31,8 +31,8 @@
 #include "update.h"
 #include "verlet.h"
 
+#include <cstring>
 #include <limits>
-#include <string.h>
 
 using namespace LAMMPS_NS;
 
diff --git a/src/fix_box_relax.cpp b/src/fix_box_relax.cpp
index 8783e12b75..e80a4db593 100644
--- a/src/fix_box_relax.cpp
+++ b/src/fix_box_relax.cpp
@@ -329,13 +329,12 @@ FixBoxRelax::FixBoxRelax(LAMMPS *lmp, int narg, char **arg) :
   // pass id_temp as 4th arg to pressure constructor
 
   id_press = utils::strdup(std::string(id) + "_press");
-  modify->add_compute(fmt::format("{} all pressure {} virial",
-                                  id_press, id_temp));
+  modify->add_compute(fmt::format("{} all pressure {} virial",id_press, id_temp));
   pflag = 1;
 
   dimension = domain->dimension;
   nrigid = 0;
-  rfix = 0;
+  rfix = nullptr;
 
   current_lifo = 0;
 }
diff --git a/src/fix_efield.cpp b/src/fix_efield.cpp
index 98cecd8a01..f752585206 100644
--- a/src/fix_efield.cpp
+++ b/src/fix_efield.cpp
@@ -428,7 +428,7 @@ double FixEfield::memory_usage()
    return energy added by fix
 ------------------------------------------------------------------------- */
 
-double FixEfield::compute_scalar(void)
+double FixEfield::compute_scalar()
 {
   if (force_flag == 0) {
     MPI_Allreduce(fsum,fsum_all,4,MPI_DOUBLE,MPI_SUM,world);
diff --git a/src/imbalance.cpp b/src/imbalance.cpp
index 80cbd8654a..e6ecacbfa0 100644
--- a/src/imbalance.cpp
+++ b/src/imbalance.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* -*- c++ -*- ----------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
diff --git a/src/imbalance_group.cpp b/src/imbalance_group.cpp
index e674338e76..bbd6bc056a 100644
--- a/src/imbalance_group.cpp
+++ b/src/imbalance_group.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -22,45 +21,43 @@ using namespace LAMMPS_NS;
 
 /* -------------------------------------------------------------------- */
 
-ImbalanceGroup::ImbalanceGroup(LAMMPS *lmp) : Imbalance(lmp), id(0), factor(0)
-{}
+ImbalanceGroup::ImbalanceGroup(LAMMPS *lmp) : Imbalance(lmp), id(nullptr), factor(nullptr) {}
 
 /* -------------------------------------------------------------------- */
 
 ImbalanceGroup::~ImbalanceGroup()
 {
-  delete [] id;
-  delete [] factor;
+  delete[] id;
+  delete[] factor;
 }
 
 /* -------------------------------------------------------------------- */
 
 int ImbalanceGroup::options(int narg, char **arg)
 {
-  if (narg < 3) error->all(FLERR,"Illegal balance weight command");
+  if (narg < 3) error->all(FLERR, "Illegal balance weight command");
 
-  num = utils::inumeric(FLERR,arg[0],false,lmp);
-  if (num < 1) error->all(FLERR,"Illegal balance weight command");
-  if (2*num+1 > narg) error->all(FLERR,"Illegal balance weight command");
+  num = utils::inumeric(FLERR, arg[0], false, lmp);
+  if (num < 1) error->all(FLERR, "Illegal balance weight command");
+  if (2 * num + 1 > narg) error->all(FLERR, "Illegal balance weight command");
 
   id = new int[num];
   factor = new double[num];
   for (int i = 0; i < num; ++i) {
-    id[i] = group->find(arg[2*i+1]);
-    if (id[i] < 0)
-      error->all(FLERR,"Unknown group in balance weight command: {}", arg[2*i+1]);
-    factor[i] = utils::numeric(FLERR,arg[2*i+2],false,lmp);
-    if (factor[i] <= 0.0) error->all(FLERR,"Illegal balance weight command");
+    id[i] = group->find(arg[2 * i + 1]);
+    if (id[i] < 0) error->all(FLERR, "Unknown group in balance weight command: {}", arg[2 * i + 1]);
+    factor[i] = utils::numeric(FLERR, arg[2 * i + 2], false, lmp);
+    if (factor[i] <= 0.0) error->all(FLERR, "Illegal balance weight command");
   }
-  return 2*num+1;
+  return 2 * num + 1;
 }
 
 /* -------------------------------------------------------------------- */
 
 void ImbalanceGroup::compute(double *weight)
 {
-  const int * const mask = atom->mask;
-  const int * const bitmask = group->bitmask;
+  const int *const mask = atom->mask;
+  const int *const bitmask = group->bitmask;
   const int nlocal = atom->nlocal;
 
   if (num == 0) return;
@@ -68,8 +65,7 @@ void ImbalanceGroup::compute(double *weight)
   for (int i = 0; i < nlocal; ++i) {
     const int imask = mask[i];
     for (int j = 0; j < num; ++j) {
-      if (imask & bitmask[id[j]])
-        weight[i] *= factor[j];
+      if (imask & bitmask[id[j]]) weight[i] *= factor[j];
     }
   }
 }
@@ -81,11 +77,10 @@ std::string ImbalanceGroup::info()
   std::string mesg = "";
 
   if (num > 0) {
-    const char * const * const names = group->names;
+    const char *const *const names = group->names;
 
     mesg += "  group weights:";
-    for (int i = 0; i < num; ++i)
-      mesg += fmt::format(" {}={}",names[id[i]],factor[i]);
+    for (int i = 0; i < num; ++i) mesg += fmt::format(" {}={}", names[id[i]], factor[i]);
     mesg += "\n";
   }
   return mesg;
diff --git a/src/imbalance_store.cpp b/src/imbalance_store.cpp
index 2437395dda..598fb88bee 100644
--- a/src/imbalance_store.cpp
+++ b/src/imbalance_store.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -21,20 +20,20 @@ using namespace LAMMPS_NS;
 
 /* -------------------------------------------------------------------- */
 
-ImbalanceStore::ImbalanceStore(LAMMPS *lmp) : Imbalance(lmp), name(0) {}
+ImbalanceStore::ImbalanceStore(LAMMPS *lmp) : Imbalance(lmp), name(nullptr) {}
 
 /* -------------------------------------------------------------------- */
 
 ImbalanceStore::~ImbalanceStore()
 {
-  delete [] name;
+  delete[] name;
 }
 
 /* -------------------------------------------------------------------- */
 
 int ImbalanceStore::options(int narg, char **arg)
 {
-  if (narg < 1) error->all(FLERR,"Illegal balance weight command");
+  if (narg < 1) error->all(FLERR, "Illegal balance weight command");
   name = utils::strdup(arg[0]);
 
   return 1;
@@ -44,13 +43,13 @@ int ImbalanceStore::options(int narg, char **arg)
 
 void ImbalanceStore::compute(double *weight)
 {
-  int flag,cols;
-  int index = atom->find_custom(name,flag,cols);
+  int flag, cols;
+  int index = atom->find_custom(name, flag, cols);
 
   // property does not exist
 
   if (index < 0 || flag != 1 || cols)
-    error->all(FLERR,"Balance weight store vector does not exist");
+    error->all(FLERR, "Balance weight store vector does not exist");
 
   double *prop = atom->dvector[index];
   const int nlocal = atom->nlocal;
@@ -61,5 +60,5 @@ void ImbalanceStore::compute(double *weight)
 
 std::string ImbalanceStore::info()
 {
-  return fmt::format("  storing weight in atom property d_{}\n",name);
+  return fmt::format("  storing weight in atom property d_{}\n", name);
 }
diff --git a/src/imbalance_time.cpp b/src/imbalance_time.cpp
index 8c5104381d..8f27938a68 100644
--- a/src/imbalance_time.cpp
+++ b/src/imbalance_time.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -30,9 +29,9 @@ ImbalanceTime::ImbalanceTime(LAMMPS *lmp) : Imbalance(lmp) {}
 
 int ImbalanceTime::options(int narg, char **arg)
 {
-  if (narg < 1) error->all(FLERR,"Illegal balance weight command");
-  factor = utils::numeric(FLERR,arg[0],false,lmp);
-  if (factor <= 0.0) error->all(FLERR,"Illegal balance weight command");
+  if (narg < 1) error->all(FLERR, "Illegal balance weight command");
+  factor = utils::numeric(FLERR, arg[0], false, lmp);
+  if (factor <= 0.0) error->all(FLERR, "Illegal balance weight command");
   return 1;
 }
 
@@ -71,14 +70,14 @@ void ImbalanceTime::compute(double *weight)
   cost += 0.1;
 
   double maxcost;
-  MPI_Allreduce(&cost,&maxcost,1,MPI_DOUBLE,MPI_MAX,world);
+  MPI_Allreduce(&cost, &maxcost, 1, MPI_DOUBLE, MPI_MAX, world);
   if (maxcost <= 0.1) return;
 
   int nlocal = atom->nlocal;
   double localwt = 0.0;
-  if (nlocal) localwt = cost/nlocal;
+  if (nlocal) localwt = cost / nlocal;
 
-  if (nlocal && localwt <= 0.0) error->one(FLERR,"Balance weight <= 0.0");
+  if (nlocal && localwt <= 0.0) error->one(FLERR, "Balance weight <= 0.0");
 
   // apply factor if specified != 1.0
   // wtlo,wthi = lo/hi values excluding 0.0 due to no atoms on this proc
@@ -87,15 +86,15 @@ void ImbalanceTime::compute(double *weight)
   // expand/contract all localwt values from lo->hi to lo->newhi
 
   if (factor != 1.0) {
-    double wtlo,wthi;
+    double wtlo, wthi;
     if (localwt == 0.0) localwt = BIG;
-    MPI_Allreduce(&localwt,&wtlo,1,MPI_DOUBLE,MPI_MIN,world);
+    MPI_Allreduce(&localwt, &wtlo, 1, MPI_DOUBLE, MPI_MIN, world);
     if (localwt == BIG) localwt = 0.0;
-    MPI_Allreduce(&localwt,&wthi,1,MPI_DOUBLE,MPI_MAX,world);
+    MPI_Allreduce(&localwt, &wthi, 1, MPI_DOUBLE, MPI_MAX, world);
     if (wtlo == wthi) return;
 
-    double newhi = wthi*factor;
-    localwt = wtlo + ((localwt-wtlo)/(wthi-wtlo)) * (newhi-wtlo);
+    double newhi = wthi * factor;
+    localwt = wtlo + ((localwt - wtlo) / (wthi - wtlo)) * (newhi - wtlo);
   }
 
   for (int i = 0; i < nlocal; i++) weight[i] *= localwt;
@@ -109,5 +108,5 @@ void ImbalanceTime::compute(double *weight)
 
 std::string ImbalanceTime::info()
 {
-  return fmt::format("  time weight factor: {}\n",factor);
+  return fmt::format("  time weight factor: {}\n", factor);
 }
diff --git a/src/imbalance_var.cpp b/src/imbalance_var.cpp
index 8679216b94..4b1099c767 100644
--- a/src/imbalance_var.cpp
+++ b/src/imbalance_var.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -25,20 +24,20 @@ using namespace LAMMPS_NS;
 
 /* -------------------------------------------------------------------- */
 
-ImbalanceVar::ImbalanceVar(LAMMPS *lmp) : Imbalance(lmp), name(0) {}
+ImbalanceVar::ImbalanceVar(LAMMPS *lmp) : Imbalance(lmp), name(nullptr) {}
 
 /* -------------------------------------------------------------------- */
 
 ImbalanceVar::~ImbalanceVar()
 {
-  delete [] name;
+  delete[] name;
 }
 
 /* -------------------------------------------------------------------- */
 
 int ImbalanceVar::options(int narg, char **arg)
 {
-  if (narg < 1) error->all(FLERR,"Illegal balance weight command");
+  if (narg < 1) error->all(FLERR, "Illegal balance weight command");
   name = utils::strdup(arg[0]);
   init(0);
 
@@ -51,10 +50,10 @@ void ImbalanceVar::init(int /*flag*/)
 {
   id = input->variable->find(name);
   if (id < 0) {
-    error->all(FLERR,"Variable name for balance weight does not exist");
+    error->all(FLERR, "Variable name for balance weight does not exist");
   } else {
     if (input->variable->atomstyle(id) == 0)
-      error->all(FLERR,"Variable for balance weight has invalid style");
+      error->all(FLERR, "Variable for balance weight has invalid style");
   }
 }
 
@@ -67,16 +66,16 @@ void ImbalanceVar::compute(double *weight)
 
   double *values;
   const int nlocal = atom->nlocal;
-  memory->create(values,nlocal,"imbalance:values");
+  memory->create(values, nlocal, "imbalance:values");
 
-  input->variable->compute_atom(id,all,values,1,0);
+  input->variable->compute_atom(id, all, values, 1, 0);
 
   int flag = 0;
   for (int i = 0; i < nlocal; i++)
     if (values[i] <= 0.0) flag = 1;
   int flagall;
-  MPI_Allreduce(&flag,&flagall,1,MPI_INT,MPI_SUM,world);
-  if (flagall) error->one(FLERR,"Balance weight <= 0.0");
+  MPI_Allreduce(&flag, &flagall, 1, MPI_INT, MPI_SUM, world);
+  if (flagall) error->one(FLERR, "Balance weight <= 0.0");
 
   for (int i = 0; i < nlocal; i++) weight[i] *= values[i];
 
@@ -87,5 +86,5 @@ void ImbalanceVar::compute(double *weight)
 
 std::string ImbalanceVar::info()
 {
-  return fmt::format("  weight variable: {}\n",name);
+  return fmt::format("  weight variable: {}\n", name);
 }
diff --git a/src/min_hftn.cpp b/src/min_hftn.cpp
index 1c9ff0b237..e743f1e1da 100644
--- a/src/min_hftn.cpp
+++ b/src/min_hftn.cpp
@@ -893,7 +893,7 @@ bool MinHFTN::compute_inner_cg_step_(const double    dTrustRadius,
    Private method calc_xinf_using_mpi_
 ------------------------------------------------------------------------- */
 
-double MinHFTN::calc_xinf_using_mpi_(void) const
+double MinHFTN::calc_xinf_using_mpi_() const
 {
   double dXInfLocal = 0.0;
   for (int  i = 0; i < nvec; i++)
@@ -1162,7 +1162,7 @@ bool MinHFTN::step_exceeds_TR_(const double    dTrustRadius,
                               which calls fix_box_relax->max_alpha
 ------------------------------------------------------------------------- */
 
-bool MinHFTN::step_exceeds_DMAX_(void) const
+bool MinHFTN::step_exceeds_DMAX_() const
 {
   double  dAlpha = dmax * sqrt((double) _nNumUnknowns);
 
@@ -1611,7 +1611,7 @@ void MinHFTN::evaluate_dir_der_(const bool      bUseForwardDiffs,
    Private method open_hftn_print_file_
 ------------------------------------------------------------------------- */
 
-void MinHFTN::open_hftn_print_file_(void)
+void MinHFTN::open_hftn_print_file_()
 {
   int  nMyRank;
   MPI_Comm_rank (world, &nMyRank);
@@ -1700,7 +1700,7 @@ void MinHFTN::hftn_print_line_(const bool    bIsStepAccepted,
    Private method close_hftn_print_file_
 ------------------------------------------------------------------------- */
 
-void MinHFTN::close_hftn_print_file_(void)
+void MinHFTN::close_hftn_print_file_()
 {
   if (_fpPrint != nullptr) fclose (_fpPrint);
   return;
diff --git a/src/npair_half_size_multi_newtoff.cpp b/src/npair_half_size_multi_newtoff.cpp
index cb06ddfb6f..4c9d9b3f62 100644
--- a/src/npair_half_size_multi_newtoff.cpp
+++ b/src/npair_half_size_multi_newtoff.cpp
@@ -12,7 +12,6 @@ es   certain rights in this software.  This software is distributed under
    See the README file in the top-level LAMMPS directory.
 ------------------------------------------------------------------------- */
 
-#include <string.h>
 #include "npair_half_size_multi_newtoff.h"
 
 #include "atom.h"
diff --git a/src/nstencil.cpp b/src/nstencil.cpp
index fdd0ddfb1b..e79bd69d29 100644
--- a/src/nstencil.cpp
+++ b/src/nstencil.cpp
@@ -346,7 +346,7 @@ void NStencil::create_setup()
     // Skip all stencils by default, initialize smax
     for (i = 0; i < n; i++) {
       for (j = 0; j < n; j++) {
-        flag_skip_multi[i][j] = 1;
+        flag_skip_multi[i][j] = true;
       }
     }
 
diff --git a/src/nstencil_full_multi_2d.cpp b/src/nstencil_full_multi_2d.cpp
index 308eab71ee..22912c5866 100644
--- a/src/nstencil_full_multi_2d.cpp
+++ b/src/nstencil_full_multi_2d.cpp
@@ -37,8 +37,8 @@ void NStencilFullMulti2d::set_stencil_properties()
 
   for (i = 0; i < n; i++) {
     for (j = 0; j < n; j++) {
-      flag_half_multi[i][j] = 0;
-      flag_skip_multi[i][j] = 0;
+      flag_half_multi[i][j] = false;
+      flag_skip_multi[i][j] = false;
       bin_collection_multi[i][j] = j;
     }
   }
diff --git a/src/nstencil_full_multi_3d.cpp b/src/nstencil_full_multi_3d.cpp
index 22e5f8b4e3..f317253baa 100644
--- a/src/nstencil_full_multi_3d.cpp
+++ b/src/nstencil_full_multi_3d.cpp
@@ -38,8 +38,8 @@ void NStencilFullMulti3d::set_stencil_properties()
 
   for (i = 0; i < n; i++) {
     for (j = 0; j < n; j++) {
-      flag_half_multi[i][j] = 0;
-      flag_skip_multi[i][j] = 0;
+      flag_half_multi[i][j] = true;
+      flag_skip_multi[i][j] = false;
       bin_collection_multi[i][j] = j;
     }
   }
diff --git a/src/nstencil_half_multi_2d.cpp b/src/nstencil_half_multi_2d.cpp
index 8bf6ce8404..08d3ed7d6d 100644
--- a/src/nstencil_half_multi_2d.cpp
+++ b/src/nstencil_half_multi_2d.cpp
@@ -43,13 +43,13 @@ void NStencilHalfMulti2d::set_stencil_properties()
     for (j = 0; j < n; j++) {
       if(cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;
 
-      flag_skip_multi[i][j] = 0;
+      flag_skip_multi[i][j] = false;
 
       if(cutcollectionsq[i][i] == cutcollectionsq[j][j]){
-        flag_half_multi[i][j] = 1;
+        flag_half_multi[i][j] = true;
         bin_collection_multi[i][j] = i;
       } else {
-        flag_half_multi[i][j] = 0;
+        flag_half_multi[i][j] = false;
         bin_collection_multi[i][j] = j;
       }
     }
diff --git a/src/nstencil_half_multi_2d_tri.cpp b/src/nstencil_half_multi_2d_tri.cpp
index ffddb55061..4de841897e 100644
--- a/src/nstencil_half_multi_2d_tri.cpp
+++ b/src/nstencil_half_multi_2d_tri.cpp
@@ -43,13 +43,13 @@ void NStencilHalfMulti2dTri::set_stencil_properties()
     for (j = 0; j < n; j++) {
       if(cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;
 
-      flag_skip_multi[i][j] = 0;
+      flag_skip_multi[i][j] = false;
 
       if(cutcollectionsq[i][i] == cutcollectionsq[j][j]){
-        flag_half_multi[i][j] = 1;
+        flag_half_multi[i][j] = true;
         bin_collection_multi[i][j] = i;
       } else {
-        flag_half_multi[i][j] = 0;
+        flag_half_multi[i][j] = false;
         bin_collection_multi[i][j] = j;
       }
     }
diff --git a/src/nstencil_half_multi_3d.cpp b/src/nstencil_half_multi_3d.cpp
index d6fae6ebec..3465663e47 100644
--- a/src/nstencil_half_multi_3d.cpp
+++ b/src/nstencil_half_multi_3d.cpp
@@ -43,13 +43,13 @@ void NStencilHalfMulti3d::set_stencil_properties()
     for (j = 0; j < n; j++) {
       if(cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;
 
-      flag_skip_multi[i][j] = 0;
+      flag_skip_multi[i][j] = false;
 
       if(cutcollectionsq[i][i] == cutcollectionsq[j][j]){
-        flag_half_multi[i][j] = 1;
+        flag_half_multi[i][j] = true;
         bin_collection_multi[i][j] = i;
       } else {
-        flag_half_multi[i][j] = 0;
+        flag_half_multi[i][j] = false;
         bin_collection_multi[i][j] = j;
       }
     }
diff --git a/src/nstencil_half_multi_3d_tri.cpp b/src/nstencil_half_multi_3d_tri.cpp
index 7625a58cd7..d7f9a8e01a 100644
--- a/src/nstencil_half_multi_3d_tri.cpp
+++ b/src/nstencil_half_multi_3d_tri.cpp
@@ -43,13 +43,13 @@ void NStencilHalfMulti3dTri::set_stencil_properties()
     for (j = 0; j < n; j++) {
       if(cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;
 
-      flag_skip_multi[i][j] = 0;
+      flag_skip_multi[i][j] = false;
 
       if(cutcollectionsq[i][i] == cutcollectionsq[j][j]){
-        flag_half_multi[i][j] = 1;
+        flag_half_multi[i][j] = true;
         bin_collection_multi[i][j] = i;
       } else {
-        flag_half_multi[i][j] = 0;
+        flag_half_multi[i][j] = false;
         bin_collection_multi[i][j] = j;
       }
     }
diff --git a/src/output.cpp b/src/output.cpp
index 90513619d3..9e29caf118 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -317,7 +317,7 @@ void Output::write(bigint ntimestep)
     if (next_restart_single == ntimestep) {
 
       std::string file = restart1;
-      std::size_t found = file.find("*");
+      std::size_t found = file.find('*');
       if (found != std::string::npos)
         file.replace(found,1,fmt::format("{}",update->ntimestep));
 
@@ -405,7 +405,7 @@ void Output::write_restart(bigint ntimestep)
 {
   if (restart_flag_single) {
     std::string file = restart1;
-    std::size_t found = file.find("*");
+    std::size_t found = file.find('*');
     if (found != std::string::npos)
       file.replace(found,1,fmt::format("{}",update->ntimestep));
     restart->write(file);
diff --git a/src/pair.cpp b/src/pair.cpp
index 16979f8023..6edc8dc831 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -758,8 +758,7 @@ void Pair::add_tally_callback(Compute *ptr)
   if (found < 0) {
     found = num_tally_compute;
     ++num_tally_compute;
-    void *p = memory->srealloc((void *)list_tally_compute,
-                               sizeof(Compute *) * num_tally_compute,
+    void *p = memory->srealloc((void *)list_tally_compute, sizeof(Compute *) * num_tally_compute,
                                "pair:list_tally_compute");
     list_tally_compute = (Compute **) p;
     list_tally_compute[num_tally_compute-1] = ptr;
diff --git a/src/pair_hybrid.cpp b/src/pair_hybrid.cpp
index 0ba16f29fa..67e0a70249 100644
--- a/src/pair_hybrid.cpp
+++ b/src/pair_hybrid.cpp
@@ -476,7 +476,7 @@ void PairHybrid::coeff(int narg, char **arg)
   // 4th arg = pair sub-style index if name used multiple times
   // allow for "none" as valid sub-style name
 
-  int multflag;
+  int multflag = 0;
   int m;
 
   for (m = 0; m < nstyles; m++) {
diff --git a/src/pair_hybrid_overlay.cpp b/src/pair_hybrid_overlay.cpp
index 09fd676dd3..db12750f40 100644
--- a/src/pair_hybrid_overlay.cpp
+++ b/src/pair_hybrid_overlay.cpp
@@ -42,7 +42,7 @@ void PairHybridOverlay::coeff(int narg, char **arg)
   // 4th arg = pair sub-style index if name used multiple times
   // allow for "none" as valid sub-style name
 
-  int multflag;
+  int multflag = 0;
   int m;
 
   for (m = 0; m < nstyles; m++) {
@@ -128,7 +128,7 @@ void PairHybridOverlay::init_svector()
 void PairHybridOverlay::copy_svector(int itype, int jtype)
 {
   int n=0;
-  Pair *this_style;
+  Pair *this_style = nullptr;
 
   // fill svector array.
   // copy data from active styles and use 0.0 for inactive ones
diff --git a/src/pair_hybrid_scaled.cpp b/src/pair_hybrid_scaled.cpp
index 367afe7809..90e30dd9b2 100644
--- a/src/pair_hybrid_scaled.cpp
+++ b/src/pair_hybrid_scaled.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -32,9 +31,8 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-PairHybridScaled::PairHybridScaled(LAMMPS *lmp)
-  : PairHybrid(lmp), fsum(nullptr), tsum(nullptr),
-    scaleval(nullptr), scaleidx(nullptr)
+PairHybridScaled::PairHybridScaled(LAMMPS *lmp) :
+    PairHybrid(lmp), fsum(nullptr), tsum(nullptr), scaleval(nullptr), scaleidx(nullptr)
 {
   nmaxfsum = -1;
 }
@@ -63,7 +61,7 @@ PairHybridScaled::~PairHybridScaled()
 
 void PairHybridScaled::compute(int eflag, int vflag)
 {
-  int i,j,m,n;
+  int i, j, m, n;
 
   // update scale values from variables where needed
 
@@ -73,13 +71,11 @@ void PairHybridScaled::compute(int eflag, int vflag)
     for (i = 0; i < nvars; ++i) {
       j = input->variable->find(scalevars[i].c_str());
       if (j < 0)
-        error->all(FLERR,"Variable '{}' not found when updating "
-                                     "scale factors",scalevars[i]);
+        error->all(FLERR, "Variable '{}' not found when updating scale factors", scalevars[i]);
       vals[i] = input->variable->compute_equal(j);
     }
     for (i = 0; i < nstyles; ++i) {
-      if (scaleidx[i] >= 0)
-        scaleval[i] = vals[scaleidx[i]];
+      if (scaleidx[i] >= 0) scaleval[i] = vals[scaleidx[i]];
     }
     delete[] vals;
   }
@@ -92,7 +88,7 @@ void PairHybridScaled::compute(int eflag, int vflag)
   if (no_virial_fdotr_compute && (vflag & VIRIAL_FDOTR))
     vflag = VIRIAL_PAIR | (vflag & ~VIRIAL_FDOTR);
 
-  ev_init(eflag,vflag);
+  ev_init(eflag, vflag);
 
   // grow fsum array if needed, and copy existing forces (usually 0.0) to it.
 
@@ -100,8 +96,8 @@ void PairHybridScaled::compute(int eflag, int vflag)
     memory->destroy(fsum);
     if (atom->torque_flag) memory->destroy(tsum);
     nmaxfsum = atom->nmax;
-    memory->create(fsum,nmaxfsum,3,"pair:fsum");
-    if (atom->torque_flag) memory->create(tsum,nmaxfsum,3,"pair:tsum");
+    memory->create(fsum, nmaxfsum, 3, "pair:fsum");
+    if (atom->torque_flag) memory->create(tsum, nmaxfsum, 3, "pair:tsum");
   }
   const int nall = atom->nlocal + atom->nghost;
   auto f = atom->f;
@@ -122,8 +118,10 @@ void PairHybridScaled::compute(int eflag, int vflag)
   // necessary so substyle will not invoke virial_fdotr_compute()
 
   int vflag_substyle;
-  if (vflag & VIRIAL_FDOTR) vflag_substyle = vflag & ~VIRIAL_FDOTR;
-  else vflag_substyle = vflag;
+  if (vflag & VIRIAL_FDOTR)
+    vflag_substyle = vflag & ~VIRIAL_FDOTR;
+  else
+    vflag_substyle = vflag;
 
   double *saved_special = save_special();
 
@@ -131,7 +129,7 @@ void PairHybridScaled::compute(int eflag, int vflag)
 
   Respa *respa = nullptr;
   respaflag = 0;
-  if (utils::strmatch(update->integrate_style,"^respa")) {
+  if (utils::strmatch(update->integrate_style, "^respa")) {
     respa = (Respa *) update->integrate;
     if (respa->nhybrid_styles > 0) respaflag = 1;
   }
@@ -140,8 +138,8 @@ void PairHybridScaled::compute(int eflag, int vflag)
 
     // clear forces and torques
 
-    memset(&f[0][0],0,nall*3*sizeof(double));
-    if (atom->torque_flag) memset(&t[0][0],0,nall*3*sizeof(double));
+    memset(&f[0][0], 0, nall * 3 * sizeof(double));
+    if (atom->torque_flag) memset(&t[0][0], 0, nall * 3 * sizeof(double));
 
     set_special(m);
 
@@ -152,20 +150,21 @@ void PairHybridScaled::compute(int eflag, int vflag)
 
       if (styles[m]->compute_flag == 0) continue;
       if (outerflag && styles[m]->respa_enable)
-        styles[m]->compute_outer(eflag,vflag_substyle);
-      else styles[m]->compute(eflag,vflag_substyle);
+        styles[m]->compute_outer(eflag, vflag_substyle);
+      else
+        styles[m]->compute(eflag, vflag_substyle);
     }
 
     // add scaled forces to global sum
     const double scale = scaleval[m];
     for (i = 0; i < nall; ++i) {
-      fsum[i][0] += scale*f[i][0];
-      fsum[i][1] += scale*f[i][1];
-      fsum[i][2] += scale*f[i][2];
+      fsum[i][0] += scale * f[i][0];
+      fsum[i][1] += scale * f[i][1];
+      fsum[i][2] += scale * f[i][2];
       if (atom->torque_flag) {
-        tsum[i][0] += scale*t[i][0];
-        tsum[i][1] += scale*t[i][1];
-        tsum[i][2] += scale*t[i][2];
+        tsum[i][0] += scale * t[i][0];
+        tsum[i][1] += scale * t[i][1];
+        tsum[i][2] += scale * t[i][2];
       }
     }
 
@@ -176,25 +175,24 @@ void PairHybridScaled::compute(int eflag, int vflag)
     if (respaflag && !respa->tally_global) continue;
 
     if (eflag_global) {
-      eng_vdwl += scale*styles[m]->eng_vdwl;
-      eng_coul += scale*styles[m]->eng_coul;
+      eng_vdwl += scale * styles[m]->eng_vdwl;
+      eng_coul += scale * styles[m]->eng_coul;
     }
     if (vflag_global) {
-      for (n = 0; n < 6; n++) virial[n] += scale*styles[m]->virial[n];
+      for (n = 0; n < 6; n++) virial[n] += scale * styles[m]->virial[n];
     }
     if (eflag_atom) {
       n = atom->nlocal;
       if (force->newton_pair) n += atom->nghost;
       double *eatom_substyle = styles[m]->eatom;
-      for (i = 0; i < n; i++) eatom[i] += scale*eatom_substyle[i];
+      for (i = 0; i < n; i++) eatom[i] += scale * eatom_substyle[i];
     }
     if (vflag_atom) {
       n = atom->nlocal;
       if (force->newton_pair) n += atom->nghost;
       double **vatom_substyle = styles[m]->vatom;
       for (i = 0; i < n; i++)
-        for (j = 0; j < 6; j++)
-          vatom[i][j] += scale*vatom_substyle[i][j];
+        for (j = 0; j < 6; j++) vatom[i][j] += scale * vatom_substyle[i][j];
     }
 
     // substyles may be CENTROID_SAME or CENTROID_AVAIL
@@ -205,17 +203,12 @@ void PairHybridScaled::compute(int eflag, int vflag)
       if (styles[m]->centroidstressflag == CENTROID_AVAIL) {
         double **cvatom_substyle = styles[m]->cvatom;
         for (i = 0; i < n; i++)
-          for (j = 0; j < 9; j++)
-            cvatom[i][j] += scale*cvatom_substyle[i][j];
+          for (j = 0; j < 9; j++) cvatom[i][j] += scale * cvatom_substyle[i][j];
       } else {
         double **vatom_substyle = styles[m]->vatom;
         for (i = 0; i < n; i++) {
-          for (j = 0; j < 6; j++) {
-            cvatom[i][j] += scale*vatom_substyle[i][j];
-          }
-          for (j = 6; j < 9; j++) {
-            cvatom[i][j] += scale*vatom_substyle[i][j-3];
-          }
+          for (j = 0; j < 6; j++) { cvatom[i][j] += scale * vatom_substyle[i][j]; }
+          for (j = 6; j < 9; j++) { cvatom[i][j] += scale * vatom_substyle[i][j - 3]; }
         }
       }
     }
@@ -233,7 +226,7 @@ void PairHybridScaled::compute(int eflag, int vflag)
       t[i][2] = tsum[i][2];
     }
   }
-  delete [] saved_special;
+  delete[] saved_special;
 
   if (vflag_fdotr) virial_fdotr_compute();
 }
@@ -244,22 +237,21 @@ void PairHybridScaled::compute(int eflag, int vflag)
 
 void PairHybridScaled::settings(int narg, char **arg)
 {
-  if (narg < 1) error->all(FLERR,"Illegal pair_style command");
-  if (lmp->kokkos && !utils::strmatch(force->pair_style,"^hybrid.*/kk$"))
-    error->all(FLERR,"Must use pair_style {}/kk with Kokkos",
-                                 force->pair_style);
+  if (narg < 1) error->all(FLERR, "Illegal pair_style command");
+  if (lmp->kokkos && !utils::strmatch(force->pair_style, "^hybrid.*/kk$"))
+    error->all(FLERR, "Must use pair_style {}/kk with Kokkos", force->pair_style);
 
   if (atom->avec->forceclearflag)
-    error->all(FLERR,"Atom style is not compatible with pair_style hybrid/scaled");
+    error->all(FLERR, "Atom style is not compatible with pair_style hybrid/scaled");
 
   // delete old lists, since cannot just change settings
 
   if (nstyles > 0) {
     for (int m = 0; m < nstyles; m++) {
       delete styles[m];
-      delete [] keywords[m];
-      if (special_lj[m])   delete [] special_lj[m];
-      if (special_coul[m]) delete [] special_coul[m];
+      delete[] keywords[m];
+      if (special_lj[m]) delete[] special_lj[m];
+      if (special_coul[m]) delete[] special_coul[m];
     }
     delete[] styles;
     delete[] keywords;
@@ -283,12 +275,12 @@ void PairHybridScaled::settings(int narg, char **arg)
 
   // allocate list of sub-styles as big as possibly needed if no extra args
 
-  styles = new Pair*[narg];
-  keywords = new char*[narg];
+  styles = new Pair *[narg];
+  keywords = new char *[narg];
   multiple = new int[narg];
 
-  special_lj = new double*[narg];
-  special_coul = new double*[narg];
+  special_lj = new double *[narg];
+  special_coul = new double *[narg];
   compute_tally = new int[narg];
 
   scaleval = new double[narg];
@@ -301,62 +293,63 @@ void PairHybridScaled::settings(int narg, char **arg)
   // call settings() with set of args that are not pair style names
   // use force->pair_map to determine which args these are
 
-  int iarg,jarg,dummy;
+  int iarg, jarg, dummy;
 
   iarg = 0;
   nstyles = 0;
-  while (iarg < narg-1) {
+  while (iarg < narg - 1) {
 
     // first process scale factor or variable
     // idx < 0 indicates constant value otherwise index in variable name list
 
     double val = 0.0;
     int idx = -1;
-    if (utils::strmatch(arg[iarg],"^v_")) {
-      for (std::size_t i=0; i < scalevars.size(); ++i) {
-        if (scalevars[i] == arg[iarg]+2) {
+    if (utils::strmatch(arg[iarg], "^v_")) {
+      for (std::size_t i = 0; i < scalevars.size(); ++i) {
+        if (scalevars[i] == arg[iarg] + 2) {
           idx = i;
           break;
         }
       }
       if (idx < 0) {
         idx = scalevars.size();
-        scalevars.push_back(arg[iarg]+2);
+        scalevars.emplace_back(arg[iarg] + 2);
       }
     } else {
-      val = utils::numeric(FLERR,arg[iarg],false,lmp);
+      val = utils::numeric(FLERR, arg[iarg], false, lmp);
     }
     scaleval[nstyles] = val;
     scaleidx[nstyles] = idx;
     ++iarg;
 
-    if (utils::strmatch(arg[iarg],"^hybrid"))
-      error->all(FLERR,"Pair style hybrid/scaled cannot have hybrid as an argument");
-    if (strcmp(arg[iarg],"none") == 0)
-      error->all(FLERR,"Pair style hybrid/scaled cannot have none as an argument");
+    if (utils::strmatch(arg[iarg], "^hybrid"))
+      error->all(FLERR, "Pair style hybrid/scaled cannot have hybrid as an argument");
+    if (strcmp(arg[iarg], "none") == 0)
+      error->all(FLERR, "Pair style hybrid/scaled cannot have none as an argument");
 
-    styles[nstyles] = force->new_pair(arg[iarg],1,dummy);
-    force->store_style(keywords[nstyles],arg[iarg],0);
+    styles[nstyles] = force->new_pair(arg[iarg], 1, dummy);
+    force->store_style(keywords[nstyles], arg[iarg], 0);
     special_lj[nstyles] = special_coul[nstyles] = nullptr;
     compute_tally[nstyles] = 1;
 
-    if ((styles[nstyles]->suffix_flag & (Suffix::INTEL|Suffix::GPU|Suffix::OMP)) != 0)
-      error->all(FLERR,"Pair style hybrid/scaled does not support "
+    if ((styles[nstyles]->suffix_flag & (Suffix::INTEL | Suffix::GPU | Suffix::OMP)) != 0)
+      error->all(FLERR,
+                 "Pair style hybrid/scaled does not support "
                  "accelerator styles");
 
     // determine list of arguments for pair style settings
     // by looking for the next known pair style name.
 
     jarg = iarg + 1;
-    while ((jarg < narg)
-           && !force->pair_map->count(arg[jarg])
-           && !lmp->match_style("pair",arg[jarg])) jarg++;
+    while ((jarg < narg) && !force->pair_map->count(arg[jarg]) &&
+           !lmp->match_style("pair", arg[jarg]))
+      jarg++;
 
     // decrement to account for scale factor except when last argument
 
     if (jarg < narg) --jarg;
 
-    styles[nstyles]->settings(jarg-iarg-1,arg+iarg+1);
+    styles[nstyles]->settings(jarg - iarg - 1, arg + iarg + 1);
     iarg = jarg;
     nstyles++;
   }
@@ -366,7 +359,7 @@ void PairHybridScaled::settings(int narg, char **arg)
   for (int i = 0; i < nstyles; i++) {
     int count = 0;
     for (int j = 0; j < nstyles; j++) {
-      if (strcmp(keywords[j],keywords[i]) == 0) count++;
+      if (strcmp(keywords[j], keywords[i]) == 0) count++;
       if (j == i) multiple[i] = count;
     }
     if (count == 1) multiple[i] = 0;
@@ -383,11 +376,10 @@ void PairHybridScaled::settings(int narg, char **arg)
    since overlay could have multiple sub-styles, sum results explicitly
 ------------------------------------------------------------------------- */
 
-double PairHybridScaled::single(int i, int j, int itype, int jtype, double rsq,
-                                double factor_coul, double factor_lj, double &fforce)
+double PairHybridScaled::single(int i, int j, int itype, int jtype, double rsq, double factor_coul,
+                                double factor_lj, double &fforce)
 {
-  if (nmap[itype][jtype] == 0)
-    error->one(FLERR,"Invoked pair single on pair style none");
+  if (nmap[itype][jtype] == 0) error->one(FLERR, "Invoked pair single on pair style none");
 
   // update scale values from variables where needed
 
@@ -397,13 +389,11 @@ double PairHybridScaled::single(int i, int j, int itype, int jtype, double rsq,
     for (i = 0; i < nvars; ++i) {
       j = input->variable->find(scalevars[i].c_str());
       if (j < 0)
-        error->all(FLERR,"Variable '{}' not found when updating "
-                                     "scale factors",scalevars[i]);
+        error->all(FLERR, "Variable '{}' not found when updating scale factors", scalevars[i]);
       vals[i] = input->variable->compute_equal(j);
     }
     for (i = 0; i < nstyles; ++i) {
-      if (scaleidx[i] >= 0)
-        scaleval[i] = vals[scaleidx[i]];
+      if (scaleidx[i] >= 0) scaleval[i] = vals[scaleidx[i]];
     }
     delete[] vals;
   }
@@ -414,23 +404,22 @@ double PairHybridScaled::single(int i, int j, int itype, int jtype, double rsq,
   double scale;
 
   for (int m = 0; m < nmap[itype][jtype]; m++) {
-    if (rsq < styles[map[itype][jtype][m]]->cutsq[itype][jtype]) {
-      if (styles[map[itype][jtype][m]]->single_enable == 0)
-        error->one(FLERR,"Pair hybrid sub-style does not support single call");
+    auto pstyle = styles[map[itype][jtype][m]];
+    if (rsq < pstyle->cutsq[itype][jtype]) {
+      if (pstyle->single_enable == 0)
+        error->one(FLERR, "Pair hybrid sub-style does not support single call");
 
       if ((special_lj[map[itype][jtype][m]] != nullptr) ||
           (special_coul[map[itype][jtype][m]] != nullptr))
-        error->one(FLERR,"Pair hybrid single calls do not support"
-                   " per sub-style special bond values");
+        error->one(FLERR, "Pair hybrid single() does not support per sub-style special_bond");
 
       scale = scaleval[map[itype][jtype][m]];
-      esum += scale * styles[map[itype][jtype][m]]->single(i,j,itype,jtype,rsq,
-                                                           factor_coul,factor_lj,fone);
+      esum += scale * pstyle->single(i, j, itype, jtype, rsq, factor_coul, factor_lj, fone);
       fforce += scale * fone;
     }
   }
 
-  if (single_extra) copy_svector(itype,jtype);
+  if (single_extra) copy_svector(itype, jtype);
   return esum;
 }
 
@@ -440,49 +429,54 @@ double PairHybridScaled::single(int i, int j, int itype, int jtype, double rsq,
 
 void PairHybridScaled::coeff(int narg, char **arg)
 {
-  if (narg < 3) error->all(FLERR,"Incorrect args for pair coefficients");
+  if (narg < 3) error->all(FLERR, "Incorrect args for pair coefficients");
   if (!allocated) allocate();
 
-  int ilo,ihi,jlo,jhi;
-  utils::bounds(FLERR,arg[0],1,atom->ntypes,ilo,ihi,error);
-  utils::bounds(FLERR,arg[1],1,atom->ntypes,jlo,jhi,error);
+  int ilo, ihi, jlo, jhi;
+  utils::bounds(FLERR, arg[0], 1, atom->ntypes, ilo, ihi, error);
+  utils::bounds(FLERR, arg[1], 1, atom->ntypes, jlo, jhi, error);
 
   // 3rd arg = pair sub-style name
   // 4th arg = pair sub-style index if name used multiple times
   // allow for "none" as valid sub-style name
 
-  int multflag;
+  int multflag = 0;
   int m;
 
   for (m = 0; m < nstyles; m++) {
     multflag = 0;
-    if (strcmp(arg[2],keywords[m]) == 0) {
+    if (strcmp(arg[2], keywords[m]) == 0) {
       if (multiple[m]) {
         multflag = 1;
-        if (narg < 4) error->all(FLERR,"Incorrect args for pair coefficients");
-        int index = utils::inumeric(FLERR,arg[3],false,lmp);
-        if (index == multiple[m]) break;
-        else continue;
-      } else break;
+        if (narg < 4) error->all(FLERR, "Incorrect args for pair coefficients");
+        int index = utils::inumeric(FLERR, arg[3], false, lmp);
+        if (index == multiple[m])
+          break;
+        else
+          continue;
+      } else
+        break;
     }
   }
 
   int none = 0;
   if (m == nstyles) {
-    if (strcmp(arg[2],"none") == 0) none = 1;
-    else error->all(FLERR,"Pair coeff for hybrid has invalid style");
+    if (strcmp(arg[2], "none") == 0)
+      none = 1;
+    else
+      error->all(FLERR, "Pair coeff for hybrid has invalid style");
   }
 
   // move 1st/2nd args to 2nd/3rd args
   // if multflag: move 1st/2nd args to 3rd/4th args
   // just copy ptrs, since arg[] points into original input line
 
-  arg[2+multflag] = arg[1];
-  arg[1+multflag] = arg[0];
+  arg[2 + multflag] = arg[1];
+  arg[1 + multflag] = arg[0];
 
   // invoke sub-style coeff() starting with 1st remaining arg
 
-  if (!none) styles[m]->coeff(narg-1-multflag,&arg[1+multflag]);
+  if (!none) styles[m]->coeff(narg - 1 - multflag, &arg[1 + multflag]);
 
   // set setflag and which type pairs map to which sub-style
   // if sub-style is none: set hybrid subflag, wipe out map
@@ -492,7 +486,7 @@ void PairHybridScaled::coeff(int narg, char **arg)
 
   int count = 0;
   for (int i = ilo; i <= ihi; i++) {
-    for (int j = MAX(jlo,i); j <= jhi; j++) {
+    for (int j = MAX(jlo, i); j <= jhi; j++) {
       if (none) {
         setflag[i][j] = 1;
         nmap[i][j] = 0;
@@ -508,7 +502,7 @@ void PairHybridScaled::coeff(int narg, char **arg)
     }
   }
 
-  if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
+  if (count == 0) error->all(FLERR, "Incorrect args for pair coefficients");
 }
 
 /* ----------------------------------------------------------------------
@@ -519,15 +513,15 @@ void PairHybridScaled::write_restart(FILE *fp)
 {
   PairHybrid::write_restart(fp);
 
-  fwrite(scaleval,sizeof(double),nstyles,fp);
-  fwrite(scaleidx,sizeof(int),nstyles,fp);
+  fwrite(scaleval, sizeof(double), nstyles, fp);
+  fwrite(scaleidx, sizeof(int), nstyles, fp);
 
   int n = scalevars.size();
-  fwrite(&n,sizeof(int),1,fp);
+  fwrite(&n, sizeof(int), 1, fp);
   for (auto var : scalevars) {
     n = var.size() + 1;
-    fwrite(&n,sizeof(int),1,fp);
-    fwrite(var.c_str(),sizeof(char),n,fp);
+    fwrite(&n, sizeof(int), 1, fp);
+    fwrite(var.c_str(), sizeof(char), n, fp);
   }
 }
 
@@ -547,23 +541,23 @@ void PairHybridScaled::read_restart(FILE *fp)
 
   int n, me = comm->me;
   if (me == 0) {
-    utils::sfread(FLERR,scaleval,sizeof(double),nstyles,fp,nullptr,error);
-    utils::sfread(FLERR,scaleidx,sizeof(int),nstyles,fp,nullptr,error);
+    utils::sfread(FLERR, scaleval, sizeof(double), nstyles, fp, nullptr, error);
+    utils::sfread(FLERR, scaleidx, sizeof(int), nstyles, fp, nullptr, error);
   }
-  MPI_Bcast(scaleval,nstyles,MPI_DOUBLE,0,world);
-  MPI_Bcast(scaleidx,nstyles,MPI_INT,0,world);
+  MPI_Bcast(scaleval, nstyles, MPI_DOUBLE, 0, world);
+  MPI_Bcast(scaleidx, nstyles, MPI_INT, 0, world);
 
   char *tmp;
-  if (me == 0) utils::sfread(FLERR,&n,sizeof(int),1,fp,nullptr,error);
-  MPI_Bcast(&n,1,MPI_INT,0,world);
+  if (me == 0) utils::sfread(FLERR, &n, sizeof(int), 1, fp, nullptr, error);
+  MPI_Bcast(&n, 1, MPI_INT, 0, world);
   scalevars.resize(n);
-  for (size_t j=0; j < scalevars.size(); ++j) {
-    if (me == 0) utils::sfread(FLERR,&n,sizeof(int),1,fp,nullptr,error);
-    MPI_Bcast(&n,1,MPI_INT,0,world);
+  for (auto &scale : scalevars) {
+    if (me == 0) utils::sfread(FLERR, &n, sizeof(int), 1, fp, nullptr, error);
+    MPI_Bcast(&n, 1, MPI_INT, 0, world);
     tmp = new char[n];
-    if (me == 0) utils::sfread(FLERR,tmp,sizeof(char),n,fp,nullptr,error);
-    MPI_Bcast(tmp,n,MPI_CHAR,0,world);
-    scalevars[j] = tmp;
+    if (me == 0) utils::sfread(FLERR, tmp, sizeof(char), n, fp, nullptr, error);
+    MPI_Bcast(tmp, n, MPI_CHAR, 0, world);
+    scale = tmp;
     delete[] tmp;
   }
 }
@@ -578,11 +572,10 @@ void PairHybridScaled::init_svector()
   // allocate svector
 
   single_extra = 0;
-  for (int m = 0; m < nstyles; m++)
-    single_extra += styles[m]->single_extra;
+  for (int m = 0; m < nstyles; m++) single_extra += styles[m]->single_extra;
 
   if (single_extra) {
-    delete [] svector;
+    delete[] svector;
     svector = new double[single_extra];
   }
 }
@@ -593,7 +586,7 @@ void PairHybridScaled::init_svector()
 
 void PairHybridScaled::copy_svector(int itype, int jtype)
 {
-  int n=0;
+  int n = 0;
   Pair *this_style;
 
   // fill svector array.
diff --git a/src/read_dump.cpp b/src/read_dump.cpp
index 82f5c969df..4a7a483cb0 100644
--- a/src/read_dump.cpp
+++ b/src/read_dump.cpp
@@ -285,7 +285,7 @@ bigint ReadDump::seek(bigint nrequest, int exact)
       ntimestep = -1;
       if (multiproc) {
         std::string multiname = files[ifile];
-        multiname.replace(multiname.find("%"),1,"0");
+        multiname.replace(multiname.find('%'),1,"0");
         readers[0]->open_file(multiname.c_str());
       } else readers[0]->open_file(files[ifile]);
 
@@ -329,7 +329,7 @@ bigint ReadDump::seek(bigint nrequest, int exact)
     for (int i = 0; i < nreader; i++) {
       if (me == 0 && i == 0) continue;    // proc 0, reader 0 already found it
       std::string multiname = files[currentfile];
-      multiname.replace(multiname.find("%"),1,fmt::format("{}",firstfile+i));
+      multiname.replace(multiname.find('%'),1,fmt::format("{}",firstfile+i));
       readers[i]->open_file(multiname.c_str());
 
       bigint step;
@@ -377,7 +377,7 @@ bigint ReadDump::next(bigint ncurrent, bigint nlast, int nevery, int nskip)
       if (ifile != currentfile) {
         if (multiproc) {
           std::string multiname = files[ifile];
-          multiname.replace(multiname.find("%"),1,"0");
+          multiname.replace(multiname.find('%'),1,"0");
           readers[0]->open_file(multiname.c_str());
         } else readers[0]->open_file(files[ifile]);
       }
@@ -431,7 +431,7 @@ bigint ReadDump::next(bigint ncurrent, bigint nlast, int nevery, int nskip)
     for (int i = 0; i < nreader; i++) {
       if (me == 0 && i == 0) continue;
       std::string multiname = files[currentfile];
-      multiname.replace(multiname.find("%"),1,fmt::format("{}",firstfile+i));
+      multiname.replace(multiname.find('%'),1,fmt::format("{}",firstfile+i));
       readers[i]->open_file(multiname.c_str());
 
       bigint step;
diff --git a/src/read_restart.cpp b/src/read_restart.cpp
index e42bb59272..5fc95b78b9 100644
--- a/src/read_restart.cpp
+++ b/src/read_restart.cpp
@@ -106,7 +106,7 @@ void ReadRestart::command(int narg, char **arg)
     utils::logmesg(lmp,"Reading restart file ...\n");
     std::string hfile = file;
     if (multiproc) {
-      hfile.replace(hfile.find("%"),1,"base");
+      hfile.replace(hfile.find('%'),1,"base");
     }
     fp = fopen(hfile.c_str(),"rb");
     if (fp == nullptr)
@@ -268,7 +268,7 @@ void ReadRestart::command(int narg, char **arg)
 
     for (int iproc = me; iproc < multiproc_file; iproc += nprocs) {
       std::string procfile = file;
-      procfile.replace(procfile.find("%"),1,fmt::format("{}",iproc));
+      procfile.replace(procfile.find('%'),1,fmt::format("{}",iproc));
       fp = fopen(procfile.c_str(),"rb");
       if (fp == nullptr)
         error->one(FLERR,"Cannot open restart file {}: {}",
@@ -332,7 +332,7 @@ void ReadRestart::command(int narg, char **arg)
 
     if (filereader) {
       std::string procfile = file;
-      procfile.replace(procfile.find("%"),1,fmt::format("{}",icluster));
+      procfile.replace(procfile.find('%'),1,fmt::format("{}",icluster));
       fp = fopen(procfile.c_str(),"rb");
       if (fp == nullptr)
         error->one(FLERR,"Cannot open restart file {}: {}", procfile, utils::getsyserror());
diff --git a/src/reset_mol_ids.cpp b/src/reset_mol_ids.cpp
index cf5bcdec6e..3ddef738d2 100644
--- a/src/reset_mol_ids.cpp
+++ b/src/reset_mol_ids.cpp
@@ -89,7 +89,7 @@ void ResetMolIDs::command(int narg, char **arg)
       iarg += 2;
     } else if (strcmp(arg[iarg],"offset") == 0) {
       if (iarg+2 > narg) error->all(FLERR,"Illegal reset_mol_ids command");
-      offset = utils::tnumeric(FLERR,arg[iarg+1],1,lmp);
+      offset = utils::tnumeric(FLERR,arg[iarg+1],true,lmp);
       if (offset < -1) error->all(FLERR,"Illegal reset_mol_ids command");
       iarg += 2;
     } else error->all(FLERR,"Illegal reset_mol_ids command");
diff --git a/src/write_data.cpp b/src/write_data.cpp
index 9016528049..82c237a07e 100644
--- a/src/write_data.cpp
+++ b/src/write_data.cpp
@@ -61,7 +61,7 @@ void WriteData::command(int narg, char **arg)
   // if filename contains a "*", replace with current timestep
 
   std::string file = arg[0];
-  std::size_t found = file.find("*");
+  std::size_t found = file.find('*');
   if (found != std::string::npos)
     file.replace(found,1,fmt::format("{}",update->ntimestep));
 
diff --git a/src/write_restart.cpp b/src/write_restart.cpp
index ddae269933..7f73d868ff 100644
--- a/src/write_restart.cpp
+++ b/src/write_restart.cpp
@@ -65,7 +65,7 @@ void WriteRestart::command(int narg, char **arg)
   // if filename contains a "*", replace with current timestep
 
   std::string file = arg[0];
-  std::size_t found = file.find("*");
+  std::size_t found = file.find('*');
   if (found != std::string::npos)
     file.replace(found,1,fmt::format("{}",update->ntimestep));
 
@@ -205,7 +205,7 @@ void WriteRestart::multiproc_options(int multiproc_caller, int mpiioflag_caller,
    file = final file name to write, except may contain a "%"
 ------------------------------------------------------------------------- */
 
-void WriteRestart::write(std::string file)
+void WriteRestart::write(const std::string &file)
 {
   // special case where reneighboring is not done in integrator
   //   on timestep restart file is written (due to build_once being set)
@@ -228,7 +228,7 @@ void WriteRestart::write(std::string file)
 
   if (me == 0) {
     std::string base = file;
-    if (multiproc) base.replace(base.find("%"),1,"base");
+    if (multiproc) base.replace(base.find('%'),1,"base");
 
     fp = fopen(base.c_str(),"wb");
     if (fp == nullptr)
@@ -290,7 +290,7 @@ void WriteRestart::write(std::string file)
     }
 
     std::string multiname = file;
-    multiname.replace(multiname.find("%"),1,fmt::format("{}",icluster));
+    multiname.replace(multiname.find('%'),1,fmt::format("{}",icluster));
 
     if (filewriter) {
       fp = fopen(multiname.c_str(),"wb");
diff --git a/src/write_restart.h b/src/write_restart.h
index 2e018e1036..54d90405b2 100644
--- a/src/write_restart.h
+++ b/src/write_restart.h
@@ -29,7 +29,7 @@ class WriteRestart : public Command {
   WriteRestart(class LAMMPS *);
   void command(int, char **);
   void multiproc_options(int, int, int, char **);
-  void write(std::string);
+  void write(const std::string &);
 
  private:
   int me, nprocs;
diff --git a/tools/binary2txt.cpp b/tools/binary2txt.cpp
index 8abaafd093..a7724ffbd2 100644
--- a/tools/binary2txt.cpp
+++ b/tools/binary2txt.cpp
@@ -29,9 +29,9 @@
 //   g++ -g -DLAMMPS_BIGBIG binarytxt.o -o binary2txt
 //   again -DLAMMPS_SMALLBIG is the default
 
-#include "stdint.h"
+#include <cstdint>
 #define __STDC_FORMAT_MACROS
-#include "inttypes.h"
+#include <cinttypes>
 
 #ifndef PRId64
 #define PRId64 "ld"
@@ -65,7 +65,7 @@ int main(int narg, char **arg)
   char boundstr[9];
 
   int maxbuf = 0;
-  double *buf = NULL;
+  double *buf = nullptr;
 
   if (narg == 1) {
     printf("Syntax: binary2txt file1 file2 ...\n");